We Keep Coding

hyperdrive effect in canvas across randomly placed circles

I'm trying to create a hyperdrive effect, like from Star Wars, where the stars have a motion trail. I've gotten as far as creating the motion trail on a single circle, it still looks like the trail is going down in the y direction and not forwards or positive in the z direction.
Also, how could I do this with (many) randomly placed circles as if they were stars?
My code is on jsfiddle (https://jsfiddle.net/5m7x5zxu/) and below:
var canvas = document.querySelector("canvas");
var context = canvas.getContext("2d");
var xPos = 180;
var yPos = 100;
var motionTrailLength = 16;
var positions = [];
function storeLastPosition(xPos, yPos) {
// push an item
positions.push({
x: xPos,
y: yPos
});
//get rid of first item
if (positions.length > motionTrailLength) {
positions.pop();
}
}
function update() {
context.clearRect(0, 0, canvas.width, canvas.height);
for (var i = positions.length-1; i > 0; i--) {
var ratio = (i - 1) / positions.length;
drawCircle(positions[i].x, positions[i].y, ratio);
}
drawCircle(xPos, yPos, "source");
var k=2;
storeLastPosition(xPos, yPos);
// update position
if (yPos > 125) {
positions.pop();
}
else{
yPos += k*1.1;
}
requestAnimationFrame(update);
}
update();
function drawCircle(x, y, r) {
if (r == "source") {
r = 1;
} else {
r*=1.1;
}
context.beginPath();
context.arc(x, y, 3, 0, 2 * Math.PI, true);
context.fillStyle = "rgba(255, 255, 255, " + parseFloat(1-r) + ")";
context.fill();
}

Canvas feedback and particles.
This type of FX can be done many ways.
You could just use a particle systems and draw stars (as lines) moving away from a central point, as the speed increase you increase the line length. When at low speed the line becomes a circle if you set ctx.lineWidth > 1 and ctx.lineCap = "round"
To add to the FX you can use render feedback as I think you have done by rendering the canvas over its self. If you render it slightly larger you get a zoom FX. If you use ctx.globalCompositeOperation = "lighter" you can increase the stars intensity as you speed up to make up for the overall loss of brightness as stars move faster.
Example
I got carried away so you will have to sift through the code to find what you need.
The particle system uses the Point object and a special array called bubbleArray to stop GC hits from janking the animation.
You can use just an ordinary array if you want. The particles are independent of the bubble array. When they have moved outside the screen they are move to a pool and used again when a new particle is needed. The update function moves them and the draw Function draws them I guess LOL
The function loop is the main loop and adds and draws particles (I have set the particle count to 400 but should handle many more)
The hyper drive is operated via the mouse button. Press for on, let go for off. (It will distort the text if it's being displayed)
The canvas feedback is set via that hyperSpeed variable, the math is a little complex. The sCurce function just limits the value to 0,1 in this case to stop alpha from going over or under 1,0. The hyperZero is just the sCurve return for 1 which is the hyper drives slowest speed.
I have pushed the feedback very close to the limit. In the first few lines of the loop function you can set the top speed if(mouse.button){ if(hyperSpeed < 1.75){ Over this value 1.75 and you will start to get bad FX, at about 2 the whole screen will just go white (I think that was where)
Just play with it and if you have questions ask in the comments.
const ctx = canvas.getContext("2d");
// very simple mouse
const mouse = {x : 0, y : 0, button : false}
function mouseEvents(e){
mouse.x = e.pageX;
mouse.y = e.pageY;
mouse.button = e.type === "mousedown" ? true : e.type === "mouseup" ? false : mouse.button;
}
["down","up","move"].forEach(name => document.addEventListener("mouse"+name,mouseEvents));
// High performance array pool using buubleArray to separate pool objects and active object.
// This is designed to eliminate GC hits involved with particle systems and
// objects that have short lifetimes but used often.
// Warning this code is not well tested.
const bubbleArray = () => {
const items = [];
var count = 0;
return {
clear(){ // warning this dereferences all locally held references and can incur Big GC hit. Use it wisely.
this.items.length = 0;
count = 0;
},
update() {
var head, tail;
head = tail = 0;
while(head < count){
if(items[head].update() === false) {head += 1 }
else{
if(tail < head){
const temp = items[head];
items[head] = items[tail];
items[tail] = temp;
}
head += 1;
tail += 1;
}
}
return count = tail;
},
createCallFunction(name, earlyExit = false){
name = name.split(" ")[0];
const keys = Object.keys(this);
if(Object.keys(this).indexOf(name) > -1){ throw new Error(`Can not create function name '${name}' as it already exists.`) }
if(!/\W/g.test(name)){
let func;
if(earlyExit){
func = `var items = this.items; var count = this.getCount(); var i = 0;\nwhile(i < count){ if (items[i++].${name}() === true) { break } }`;
}else{
func = `var items = this.items; var count = this.getCount(); var i = 0;\nwhile(i < count){ items[i++].${name}() }`;
}
!this.items && (this.items = items);
this[name] = new Function(func);
}else{ throw new Error(`Function name '${name}' contains illegal characters. Use alpha numeric characters.`) }
},
callEach(name){var i = 0; while(i < count){ if (items[i++][name]() === true) { break } } },
each(cb) { var i = 0; while(i < count){ if (cb(items[i], i++) === true) { break } } },
next() { if (count < items.length) { return items[count ++] } },
add(item) {
if(count === items.length){
items.push(item);
count ++;
}else{
items.push(items[count]);
items[count++] = item;
}
return item;
},
getCount() { return count },
}
}
// Helpers rand float, randI random Int
// doFor iterator
// sCurve curve input -Infinity to Infinity out -1 to 1
// randHSLA creates random colour
// CImage, CImageCtx create image and image with context attached
const randI = (min, max = min + (min = 0)) => (Math.random() * (max - min) + min) | 0;
const rand = (min = 1, max = min + (min = 0)) => Math.random() * (max - min) + min;
const doFor = (count, cb) => { var i = 0; while (i < count && cb(i++) !== true); }; // the ; after while loop is important don't remove
const sCurve = (v,p) => (2 / (1 + Math.pow(p,-v))) -1;
const randHSLA = (h, h1, s = 100, s1 = 100, l = 50, l1 = 50, a = 1, a1 = 1) => { return `hsla(${randI(h,h1) % 360},${randI(s,s1)}%,${randI(l,l1)}%,${rand(a,a1)})` }
const CImage = (w = 128, h = w) => (c = document.createElement("canvas"),c.width = w,c.height = h, c);
const CImageCtx = (w = 128, h = w) => (c = CImage(w,h), c.ctx = c.getContext("2d"), c);
// create image to hold text
var textImage = CImageCtx(1024, 1024);
var c = textImage.ctx;
c.fillStyle = "#FF0";
c.font = "64px arial black";
c.textAlign = "center";
c.textBaseline = "middle";
const text = "HYPER,SPEED FX,VII,,Battle of Jank,,Hold the mouse,button to increase,speed.".split(",");
text.forEach((line,i) => { c.fillText(line,512,i * 68 + 68) });
const maxLines = text.length * 68 + 68;
function starWarIntro(image,x1,y1,x2,y2,pos){
var iw = image.width;
var ih = image.height;
var hh = (x2 - x1) / (y2 - y1); // Slope of left edge
var w2 = iw / 2; // half width
var z1 = w2 - x1; // Distance (z) to first line
var z2 = (z1 / (w2 - x2)) * z1 - z1; // distance (z) between first and last line
var sk,t3,t3a,z3a,lines, z3, dd = 0, a = 0, as = 2 / (y2 - y1);
for (var y = y1; y < y2 && dd < maxLines; y++) { // for each line
t3 = ((y - y1) * hh) + x1; // get scan line top left edge
t3a = (((y+1) - y1) * hh) + x1; // get scan line bottom left edge
z3 = (z1 / (w2 - t3)) * z1; // get Z distance to top of this line
z3a = (z1 / (w2 - t3a)) * z1; // get Z distance to bottom of this line
dd = ((z3 - z1) / z2) * ih; // get y bitmap coord
a += as;
ctx.globalAlpha = a < 1 ? a : 1;
dd += pos; // kludge for this answer to make text move
// does not move text correctly
lines = ((z3a - z1) / z2) * ih-dd; // get number of lines to copy
ctx.drawImage(image, 0, dd , iw, lines, t3, y, w - t3 * 2, 1.5);
}
}
// canvas settings
var w = canvas.width;
var h = canvas.height;
var cw = w / 2; // center
var ch = h / 2;
// diagonal distance used to set point alpha (see point update)
var diag = Math.sqrt(w * w + h * h);
// If window size is changed this is called to resize the canvas
// It is not called via the resize event as that can fire to often and
// debounce makes it feel sluggish so is called from main loop.
function resizeCanvas(){
points.clear();
canvas.width = innerWidth;
canvas.height = innerHeight;
w = canvas.width;
h = canvas.height;
cw = w / 2; // center
ch = h / 2;
diag = Math.sqrt(w * w + h * h);
}
// create array of points
const points = bubbleArray();
// create optimised draw function itterator
points.createCallFunction("draw",false);
// spawns a new star
function spawnPoint(pos){
var p = points.next();
p = points.add(new Point())
if (p === undefined) { p = points.add(new Point()) }
p.reset(pos);
}
// point object represents a single star
function Point(pos){ // this function is duplicated as reset
if(pos){
this.x = pos.x;
this.y = pos.y;
this.dead = false;
}else{
this.x = 0;
this.y = 0;
this.dead = true;
}
this.alpha = 0;
var x = this.x - cw;
var y = this.y - ch;
this.dir = Math.atan2(y,x);
this.distStart = Math.sqrt(x * x + y * y);
this.speed = rand(0.01,1);
this.col = randHSLA(220,280,100,100,50,100);
this.dx = Math.cos(this.dir) * this.speed;
this.dy = Math.sin(this.dir) * this.speed;
}
Point.prototype = {
reset : Point, // resets the point
update(){ // moves point and returns false when outside
this.speed *= hyperSpeed; // increase speed the more it has moved
this.x += Math.cos(this.dir) * this.speed;
this.y += Math.sin(this.dir) * this.speed;
var x = this.x - cw;
var y = this.y - ch;
this.alpha = (Math.sqrt(x * x + y * y) - this.distStart) / (diag * 0.5 - this.distStart);
if(this.alpha > 1 || this.x < 0 || this.y < 0 || this.x > w || this.h > h){
this.dead = true;
}
return !this.dead;
},
draw(){ // draws the point
ctx.strokeStyle = this.col;
ctx.globalAlpha = 0.25 + this.alpha *0.75;
ctx.beginPath();
ctx.lineTo(this.x - this.dx * this.speed, this.y - this.dy * this.speed);
ctx.lineTo(this.x, this.y);
ctx.stroke();
}
}
const maxStarCount = 400;
const p = {x : 0, y : 0};
var hyperSpeed = 1.001;
const alphaZero = sCurve(1,2);
var startTime;
function loop(time){
if(startTime === undefined){
startTime = time;
}
if(w !== innerWidth || h !== innerHeight){
resizeCanvas();
}
// if mouse down then go to hyper speed
if(mouse.button){
if(hyperSpeed < 1.75){
hyperSpeed += 0.01;
}
}else{
if(hyperSpeed > 1.01){
hyperSpeed -= 0.01;
}else if(hyperSpeed > 1.001){
hyperSpeed -= 0.001;
}
}
var hs = sCurve(hyperSpeed,2);
ctx.globalAlpha = 1;
ctx.setTransform(1,0,0,1,0,0); // reset transform
//==============================================================
// UPDATE the line below could be the problem. Remove it and try
// what is under that
//==============================================================
//ctx.fillStyle = `rgba(0,0,0,${1-(hs-alphaZero)*2})`;
// next two lines are the replacement
ctx.fillStyle = "Black";
ctx.globalAlpha = 1-(hs-alphaZero) * 2;
//==============================================================
ctx.fillRect(0,0,w,h);
// the amount to expand canvas feedback
var sx = (hyperSpeed-1) * cw * 0.1;
var sy = (hyperSpeed-1) * ch * 0.1;
// increase alpha as speed increases
ctx.globalAlpha = (hs-alphaZero)*2;
ctx.globalCompositeOperation = "lighter";
// draws feedback twice
ctx.drawImage(canvas,-sx, -sy, w + sx*2 , h + sy*2)
ctx.drawImage(canvas,-sx/2, -sy/2, w + sx , h + sy)
ctx.globalCompositeOperation = "source-over";
// add stars if count < maxStarCount
if(points.getCount() < maxStarCount){
var cent = (hyperSpeed - 1) *0.5; // pulls stars to center as speed increases
doFor(10,()=>{
p.x = rand(cw * cent ,w - cw * cent); // random screen position
p.y = rand(ch * cent,h - ch * cent);
spawnPoint(p)
})
}
// as speed increases make lines thicker
ctx.lineWidth = 2 + hs*2;
ctx.lineCap = "round";
points.update(); // update points
points.draw(); // draw points
ctx.globalAlpha = 1;
// scroll the perspective star wars text FX
var scrollTime = (time - startTime) / 5 - 2312;
if(scrollTime < 1024){
starWarIntro(textImage,cw - h * 0.5, h * 0.2, cw - h * 3, h , scrollTime );
}
requestAnimationFrame(loop);
}
requestAnimationFrame(loop);
canvas { position : absolute; top : 0px; left : 0px; }
<canvas id="canvas"></canvas>

Here's another simple example, based mainly on the same idea as Blindman67, concetric lines moving away from center at different velocities (the farther from center, the faster it moves..) also no recycling pool here.
"use strict"
var c = document.createElement("canvas");
document.body.append(c);
var ctx = c.getContext("2d");
var w = window.innerWidth;
var h = window.innerHeight;
var ox = w / 2;
var oy = h / 2;
c.width = w; c.height = h;
const stars = 120;
const speed = 0.5;
const trailLength = 90;
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, w, h);
ctx.fillStyle = "#fff"
ctx.fillRect(ox, oy, 1, 1);
init();
function init() {
var X = [];
var Y = [];
for(var i = 0; i < stars; i++) {
var x = Math.random() * w;
var y = Math.random() * h;
X.push( translateX(x) );
Y.push( translateY(y) );
}
drawTrails(X, Y)
}
function translateX(x) {
return x - ox;
}
function translateY(y) {
return oy - y;
}
function getDistance(x, y) {
return Math.sqrt(x * x + y * y);
}
function getLineEquation(x, y) {
return function(n) {
return y / x * n;
}
}
function drawTrails(X, Y) {
var count = 1;
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, w, h);
function anim() {
for(var i = 0; i < X.length; i++) {
var x = X[i];
var y = Y[i];
drawNextPoint(x, y, count);
}
count+= speed;
if(count < trailLength) {
window.requestAnimationFrame(anim);
}
else {
init();
}
}
anim();
}
function drawNextPoint(x, y, step) {
ctx.fillStyle = "#fff";
var f = getLineEquation(x, y);
var coef = Math.abs(x) / 100;
var dist = getDistance( x, y);
var sp = speed * dist / 100;
for(var i = 0; i < sp; i++) {
var newX = x + Math.sign(x) * (step + i) * coef;
var newY = translateY( f(newX) );
ctx.fillRect(newX + ox, newY, 1, 1);
}
}
body {
overflow: hidden;
}
canvas {
position: absolute;
left: 0;
top: 0;
}

Javascript 3d Terrain Without Three.js

I have searched around but I can't find anything like what I'm trying to do that doesn't use Three.js in some way (I can't use Three.js because my computer is too old to support Webgl). Here's what I've got so far:
HTML:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="terrain.js"></script>
<title>Terrain</title>
</head>
<body>
<canvas id="canvas" height="400" width="400"></canvas>
</body>
</html>
Javascript:
var canvas, ctx, row1 = [], row2 = [], intensity = 15, width = 20, height = 20, centery = 200, centerx = 200, minus, delta = 1.6, nu = .02;
window.onload = function() {
canvas = document.getElementById('canvas'), ctx = canvas.getContext('2d');
ctx.lineStyle = '#000'
for (var i = 0; i < height; i++) {
row2 = [];
minus = 200
for (var j = 0; j < width; j++) {
row2[j] = {
x: centerx - (minus * (delta * (nu * i))),
y: Math.floor(Math.random() * intensity) + (height * i)
}
minus -= height;
}
ctx.beginPath();
ctx.moveTo(row2[0].x,row2[0].y)
for (var k = 1; k < row2.length; k++) {
ctx.lineTo(row2[k].x,row2[k].y)
if (k == row2.length) {ctx.clostPath()}
}
ctx.stroke();
if (row1[0] && row2[0]) {
for (var l = 0; l < row2.length; l++) {
ctx.beginPath();
ctx.moveTo(row2[l].x,row2[l].y)
ctx.lineTo(row1[l].x,row1[l].y)
ctx.closePath();
ctx.stroke();
}
}
row1 = row2;
}
}
Currently, the result looks like a Christmas tree but I want it to look more like actual 3d wireframe terrain.

3D wire frame basics
3D can be done on any systems that can move pixels. Thought not by dedicated hardware Javascript can do alright if you are after simple 3d.
This answers shows how to create a mesh, rotate and move it, create a camera and move it, and project the whole lot onto the 2D canvas using simple moveTo, and lineTo calls.
This answer is a real rush job so apologies for the typos (if any) and messy code. Will clean it up in the come few days (if time permits). Any questions please do ask in the comments.
Update
I have not done any basic 3D for some time so having a little fun I have added to the answer with more comments in the code and added some extra functionality.
vec3 now has normalise, dot, cross functions.
mat now has lookat function and is ready for much more if needed.
mesh now maintains its own world matrix
Added box, and line that create box and line meshs
Created a second vector type vec3S (S for simple) that is just coordinates no functionality
Demo now shows how to add more objects, position them in the scene, use a lookat transform
Details about the code.
The code below is the basics of 3D. It has a mesh object to create objects out of 3D points (vertices) connected via lines.
Simple transformation for rotating, moving and scaling a model so it can be placed in the scene.
A very very basic camera that can only look forward, move up,down, left,right, in and out. And the focal length can be changed.
Only for lines as there is no depth sorting.
The demo does not clip to the camera front plane, but rather just ignores lines that have any part behind the camera;
You will have to work out the rest from the comments, 3D is a big subject and any one of the features is worth a question / answer all its own.
Oh and coordinates in 3D are origin in center of canvas. Y positive down, x positive right, and z positive into the screen. projection is basic so when you have perspective set to 400 than a object at 400 units out from camera will have a one to one match with pixel size.
var ctx = canvas.getContext("2d");
// some usage of vecs does not need the added functionality
// and will use the basic version
const vec3Basic = { x : 0, y : 0, z: 0};
const vec3Def = {
// Sets the vector scalars
// Has two signatures
// setVal(x,y,z) sets vector to {x,y,z}
// setVal(vec) set this vector to vec
setVal(x,y = x.y,z = x.z + (x = x.x) * 0){
this.x = x;
this.y = y;
this.z = z;
},
// subtract v from this vector
// Has two signatures
// setVal(v) subtract v from this returning a new vec3
// setVal(v,vec) subtract v from this returning result in retVec
sub(v,retVec = vec3()){
retVec.x = this.x - v.x;
retVec.y = this.y - v.y;
retVec.z = this.z - v.z;
return retVec;
},
// Cross product of two vectors this and v.
// Cross product can be thought of as get the vector
// that is perpendicular to the plane described by the two vector we are crossing
// Has two signatures
// cross(vec); // returns a new vec3 as the cross product of this and vec
// cross(vec, retVec); // set retVec as the cross product
cross (v, retVec = vec3()){
retVec.x = this.y * v.z - this.z * v.y;
retVec.y = this.z * v.x - this.x * v.z;
retVec.z = this.x * v.y - this.y * v.x;
return retVec;
},
// Dot product
// Dot product of two vectors if both normalized can be thought of as finding the cos of the angle
// between two vectors. If not normalised the dot product will give you < 0 if v points away from
// the plane that this vector is perpendicular to, if > 0 the v points in the same direction as the
// plane perpendicular to this vector. if 0 then v is at 90 degs to the plane this is perpendicular to
// Using vector dot on its self is the same as getting the length squared
// dot(vec3); // returns a number as a float
dot (v){ return this.x * v.x + this.y * v.y + this.z * this.z },
// normalize normalizes a vector. A normalized vector has length equale to 1 unit
// Has two signitures
// normalise(); normalises this vector returning this
// normalize(retVec); normalises this vector but puts the normalised vector in retVec returning
// returning retVec. Thiis is unchanged.
normalize(retVec = this){
// could have used len = this.dot(this) but for speed all functions will do calcs internaly
const len = Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);
// it is assumed that all vector are valid (have length) so no test is made to avoid
// the divide by zero that will happen for invalid vectors.
retVec.x = this.x / len;
retVec.y = this.y / len;
retVec.z = this.z / len;
}
}
// Created as a singleton to close over working constants
const matDef = (()=>{
// to seed up vector math the following closed over vectors are used
// rather than create and dispose of vectors for every operation needing them
// Currently not used
const V1 = vec3();
return {
// The matrix is just 3 pointers one for each axis
// They represent the direction and scale in 3D of each axis
// when you transform a point x,y,z you move x along the x axis,
// then y along y and z along the z axis
xAxis : null,
yAxis : null,
zAxis : null,
// this is a position x,y,z and represents where in 3D space an objects
// center coordinate (0,0,0) will be. It is simply added to a point
// after it has been moved along the 3 axis.
pos : null,
// This function does most of the 3D work in most 3D environments.
// It rotates, scales, translates, and a whole lot more.
// It is a cut down of the full 4 by 4 3D matrix you will find in
// Libraries like three.js
transformVec3(vec,retVec = {}){
retVec.x = vec.x * this.xAxis.x + vec.y * this.yAxis.x + vec.z * this.zAxis.x + this.pos.x;
retVec.y = vec.x * this.xAxis.y + vec.y * this.yAxis.y + vec.z * this.zAxis.y + this.pos.y;
retVec.z = vec.x * this.xAxis.z + vec.y * this.yAxis.z + vec.z * this.zAxis.z + this.pos.z;
return retVec;
},
// resets the matrix
identity(){ // default matrix
this.xAxis.setVal(1,0,0); // x 1 unit long in the x direction
this.yAxis.setVal(0,1,0); // y 1 unit long in the y direction
this.zAxis.setVal(0,0,1); // z 1 unit long in the z direction
this.pos.setVal(0,0,0); // and position at the origin.
},
init(){ // need to call this before using due to the way I create these
// objects.
this.xAxis = vec3(1,0,0);
this.yAxis = vec3(0,1,0);
this.zAxis = vec3(0,0,1);
this.pos = vec3(0,0,0);
return this; // must have this line for the constructor function to return
},
setRotateY(amount){
var x = Math.cos(amount);
var y = Math.sin(amount);
this.xAxis.x = x;
this.xAxis.y = 0;
this.xAxis.z = y;
this.zAxis.x = -y;
this.zAxis.y = 0;
this.zAxis.z = x;
},
// creates a look at transform from the current position
// point is a vec3.
// No check is made to see if look at is at pos which will invalidate this matrix
// Note scale is lost in this operation.
lookAt(point){
// zAxis along vector from pos to point
this.pos.sub(point,this.zAxis).normalize();
// use y as vertical reference
this.yAxis.x = 0;
this.yAxis.y = 1;
this.yAxis.z = 0;
// get x axis perpendicular to the plane described by z and y axis
// need to normalise as z and y axis may not be at 90 deg
this.yAxis.cross(this.zAxis,this.xAxis).normalize();
// Get the y axis that is perpendicular to z and x axis
// Normalise is not really needed but rounding errors can be problematic
// so the normalise just fixes some of the rounding errors.
this.zAxis.cross(this.xAxis,this.yAxis).normalize();
},
}
})();
// Mesh object has buffers for the
// model as verts
// transformed mesh as tVerts
// projected 2D verts as dVerts (d for display)
// An a array of lines. Each line has two indexes that point to the
// vert that define their ends.
// Buffers are all preallocated to stop GC slowing everything down.
const meshDef = {
addVert(vec){
this.verts.push(vec);
// vec3(vec) in next line makes a copy of the vec. This is important
// as using the same vert in the two buffers will result in strange happenings.
this.tVerts.push(vec3S(vec)); // transformed verts pre allocated so GC does not bite
this.dVerts.push({x:0,y:0}); // preallocated memory for displaying 2d projection
// when x and y are zero this means that it is not visible
return this.verts.length - 1;
},
addLine(index1,index2){
this.lines.push(index1,index2);
},
transform(matrix = this.matrix){
for(var i = 0; i < this.verts.length; i++){
matrix.transformVec3(this.verts[i],this.tVerts[i]);
}
},
eachVert(callback){
for(var i = 0; i < this.verts.length; i++){
callback(this.tVerts[i],i);
}
},
eachLine(callback){
for(var i = 0; i < this.lines.length; i+= 2){
var ind1 = this.lines[i];
var v1 = this.dVerts[ind1]; // get the start
if(v1.x !== 0 && v1.y !== 0){ // is valid
var ind2 = this.lines[i+ 1]; // get end of line
var v2 = this.dVerts[ind2];
if(v2.x !== 0 && v2.y !== 0){ // is valid
callback(v1,v2);
}
}
}
},
init(){ // need to call this befor using
this.verts = [];
this.lines = [];
this.dVerts = [];
this.tVerts = [];
this.matrix = mat();
return this; // must have this line for the construtor function to return
}
}
const cameraDef = {
projectMesh(mesh){ // create a 2D mesh
mesh.eachVert((vert,i)=>{
var z = (vert.z + this.position.z);
if(z < 0){ // is behind the camera then ignor it
mesh.dVerts[i].x = mesh.dVerts[i].y = 0;
}else{
var s = this.perspective / z;
mesh.dVerts[i].x = (vert.x + this.position.x) * s;
mesh.dVerts[i].y = (vert.y + this.position.y) * s;
}
})
},
drawMesh(mesh){ // renders the 2D mesh
ctx.beginPath();
mesh.eachLine((v1,v2)=>{
ctx.moveTo(v1.x,v1.y);
ctx.lineTo(v2.x,v2.y);
})
ctx.stroke();
}
}
// vec3S creates a basic (simple) vector
// 3 signatures
//vec3S(); // return vec 1,0,0
//vec3S(vec); // returns copy of vec
//vec3S(x,y,z); // returns {x,y,z}
function vec3S(x = {x:1,y:0,z:0},y = x.y ,z = x.z + (x = x.x) * 0){ // a 3d point
return Object.assign({},vec3Basic,{x, y, z});
}
// vec3S creates a basic (simple) vector
// 3 signatures
//vec3S(); // return vec 1,0,0
//vec3S(vec); // returns copy of vec
//vec3S(x,y,z); // returns {x,y,z}
function vec3(x = {x:1,y:0,z:0},y = x.y ,z = x.z + (x = x.x) * 0){ // a 3d point
return Object.assign({},vec3Def,{x,y,z});
}
function mat(){ // matrix used to rotate scale and move a 3d point
return Object.assign({},matDef).init();
}
function mesh(){ // this is for storing objects as points in 3d and lines conecting points
return Object.assign({},meshDef).init();
}
function camera(perspective,position){ // this is for displaying 3D
return Object.assign({},cameraDef,{perspective,position});
}
// grid is the number of grids x,z and size is the overal size for x
function createLandMesh(gridx,gridz,size,maxHeight){
var m = mesh(); // create a mesh
var hs = size/2 ;
var step = size / gridx;
for(var z = 0; z < gridz; z ++){
for(var x = 0; x < gridx; x ++){
// create a vertex. Y is random
m.addVert(vec3S(x * step - hs, (Math.random() * maxHeight), z * step-hs)); // create a vert
}
}
for(var z = 0; z < gridz-1; z ++){
for(var x = 0; x < gridx-1; x ++){
if(x < gridx -1){ // dont go past end
m.addLine(x + z * gridx,x + 1 + z * gridx); // add line across
}
if(z < gridz - 1){ // dont go past end
m.addLine(x + z * (gridx-1),x + 1 + (z + 1) * (gridx-1));
}
}
}
return m;
}
function createBoxMesh(size){
var s = size / 2;
var m = mesh(); // create a mesh
// add bottom
m.addVert(vec3S(-s,-s,-s));
m.addVert(vec3S( s,-s,-s));
m.addVert(vec3S( s, s,-s));
m.addVert(vec3S(-s, s,-s));
// add top verts
m.addVert(vec3S(-s,-s, s));
m.addVert(vec3S( s,-s, s));
m.addVert(vec3S( s, s, s));
m.addVert(vec3S(-s, s, s));
// add lines
/// bottom lines
m.addLine(0,1);
m.addLine(1,2);
m.addLine(2,3);
m.addLine(3,0);
/// top lines
m.addLine(4,5);
m.addLine(5,6);
m.addLine(6,7);
m.addLine(7,4);
// side lines
m.addLine(0,4);
m.addLine(1,5);
m.addLine(2,6);
m.addLine(3,7);
return m;
}
function createLineMesh(v1 = vec3S(),v2 = vec3S()){
const m = mesh();
m.addVert(v1);
m.addVert(v2);
m.addLine(0,1);
return m;
}
//Create a land mesh grid 20 by 20 and 400 units by 400 units in size
var land = createLandMesh(20,20,400,20); // create a land mesh
var box = createBoxMesh(50);
var box1 = createBoxMesh(25);
var line = createLineMesh(); // line conecting boxes
line.tVerts[0] = box.matrix.pos; // set the line transformed tVect[0] to box matrix.pos
line.tVerts[1] = box1.matrix.pos; // set the line transformed tVect[0] to box1 matrix.pos
var cam = camera(200,vec3(0,0,0)); // create a projection with focal len 200 and at 0,0,0
box.matrix.pos.setVal(0,-100,400);
box1.matrix.pos.setVal(0,-100,400);
land.matrix.pos.setVal(0,100,300); // move down 100, move away 300
var w = canvas.width;
var h = canvas.height;
var cw = w / 2; // center of canvas
var ch = h / 2;
function update(timer){
// next section just maintains canvas size and resets state and clears display
if (canvas.width !== innerWidth || canvas.height !== innerHeight) {
cw = (w = canvas.width = innerWidth) /2;
ch = (h = canvas.height = innerHeight) /2;
}
ctx.setTransform(1,0,0,1,0,0); // reset transform
ctx.globalAlpha = 1; // reset alpha
ctx.fillStyle = "black";
ctx.fillRect(0,0,canvas.width,canvas.height);
// end of standard canvas maintenance
// render from center of canvas by setting canvas origin to center
ctx.setTransform(1,0,0,1,canvas.width / 2,canvas.height / 2)
land.matrix.setRotateY(timer/1000); // set matrix to rotation position
land.transform();
// move the blue box
var t = timer/1000;
box1.matrix.pos.setVal(Math.sin(t / 2.1) * 100,Math.sin( t / 3.2) * 100, Math.sin(t /5.3) * 90+300);
// Make the cyan box look at the blue box
box.matrix.lookAt(box1.matrix.pos);
// Transform boxes from local to world space
box1.transform();
box.transform();
// set camera x,y pos to mouse pos;
cam.position.x = mouse.x - cw;
cam.position.y = mouse.y - ch;
// move in and out
if (mouse.buttonRaw === 1) { cam.position.z -= 1 }
if (mouse.buttonRaw === 4) {cam.position.z += 1 }
// Converts mesh transformed verts to 2D screen coordinates
cam.projectMesh(land);
cam.projectMesh(box);
cam.projectMesh(box1);
cam.projectMesh(line);
// Draw each mesh in turn
ctx.strokeStyle = "#0F0";
cam.drawMesh(land);
ctx.strokeStyle = "#0FF";
cam.drawMesh(box);
ctx.strokeStyle = "#00F";
cam.drawMesh(box1);
ctx.strokeStyle = "#F00";
cam.drawMesh(line);
ctx.setTransform(1,0,0,1,cw,ch / 4);
ctx.font = "20px arial";
ctx.textAlign = "center";
ctx.fillStyle = "yellow";
ctx.fillText("Move mouse to move camera. Left right mouse move in out",0,0)
requestAnimationFrame(update);
}
requestAnimationFrame(update);
// A mouse handler from old lib of mine just to give some interaction
// not needed for the 3d
var mouse = (function () {
var m; // alias for mouse
var mouse = {
x : 0, y : 0, // mouse position
buttonRaw : 0,
buttonOnMasks : [0b1, 0b10, 0b100], // mouse button on masks
buttonOffMasks : [0b110, 0b101, 0b011], // mouse button off masks
bounds : null,
event(e) {
m.bounds = m.element.getBoundingClientRect();
m.x = e.pageX - m.bounds.left - scrollX;
m.y = e.pageY - m.bounds.top - scrollY;
if (e.type === "mousedown") { m.buttonRaw |= m.buttonOnMasks[e.which - 1] }
else if (e.type === "mouseup") { m.buttonRaw &= m.buttonOffMasks[e.which - 1] }
e.preventDefault();
},
start(element) {
m.element = element === undefined ? document : element;
"mousemove,mousedown,mouseup".split(",").forEach(name => document.addEventListener(name, mouse.event) );
document.addEventListener("contextmenu", (e) => { e.preventDefault() }, false);
return mouse;
},
}
m = mouse;
return mouse;
})().start(canvas);
canvas { position:absolute; top : 0px; left : 0px;}
<canvas id="canvas"></canvas>

Get relative X and Y on transforming canvas [duplicate]

I implemented a zoom function in my canvas just like this one: Zoom in on a point (using scale and translate)
Now I need to calculate the position of the mouse in relation to the canvas, I first tried like this:
var rect = this._canvas.getBoundingClientRect();
var x = ((event.clientX - rect.left) / (rect.right - rect.left) * this._canvas.width);
var y = ((event.clientY - rect.top) / (rect.bottom - rect.top) * this._canvas.height);
This works excellent until I zoom... I tried to do it like this:
var x = ((event.clientX - rect.left) / (rect.right - rect.left) * this._canvas.width) - this._canvas.offsetLeft ;
var y = ((event.clientY - rect.top) / (rect.bottom - rect.top) * this._canvas.height) - offset.top this._canvas.offSetTop ;
Any hint ? Or should I better use a JS library to interact with the canvas element ? If so, do you have any experience ?

Inverse Matrix
This answer include rotation as well because the scale is part of the rotation in the matrix you can't really exclude one or the other. But you can ignore the rotation (set it as zero) and just set scale and translation and it does what you want.
The inverse transform. It basically does the reverse of the standard 2D transformations. It will require that you keep track of the transformations so you can create the inverse transform, this can prove problematic in complex transforms if you wish to use ctx.rotation, ctx.scale, ctx.translate or ctx.transform. As you requirements are simple I have created a simple function to do the minimum transformation.
The following creates both the transformation matrix and the inverse transform as two arrays called matrix and invMatrix. The arguments are translation x,y (in canvas coordinates), scale, and rotation.
var matrix = [1,0,0,1,0,0];
var invMatrix = [1,0,0,1];
function createMatrix(x, y, scale, rotate){
var m = matrix; // just to make it easier to type and read
var im = invMatrix; // just to make it easier to type and read
// create the rotation and scale parts of the matrix
m[3] = m[0] = Math.cos(rotate) * scale;
m[2] = -(m[1] = Math.sin(rotate) * scale);
// add the translation
m[4] = x;
m[5] = y;
// calculate the inverse transformation
// first get the cross product of x axis and y axis
cross = m[0] * m[3] - m[1] * m[2];
// now get the inverted axis
im[0] = m[3] / cross;
im[1] = -m[1] / cross;
im[2] = -m[2] / cross;
im[3] = m[0] / cross;
}
Using the function
To use the function is simple. Just call with the desired values for position, scale and rotation.
Applying the inverse
To get the world coordinates (the transformed coordinates) from a pixel space (screen x, y) you need to apply the inverse transform
function toWorld(x,y){
var xx, yy, m, result;
m = invMatrix;
xx = x - matrix[4]; // remove the translation
yy = y - matrix[5]; // by subtracting the origin
// return the point {x:?,y:?} by multiplying xx,yy by the inverse matrix
return {
x: xx * m[0] + yy * m[2],
y: xx * m[1] + yy * m[3]
}
}
So if you want the mouse position in world space
var mouseWorldSpace = toWorld(mouse.x,mouse.y); // get the world space coordinates of the mouse
The function will convert any coordinate that is in screen space to the correct coordinate in world space.
Setting the 2D context transform
To use the transform you can set the 2D context transformation directly with
var m = matrix;
ctx.setTransform(m[0], m[1], m[2], m[3], m[4], m[5]);
Demo
And a demo to show it in use. A lot of extra code but I am sure you can find the parts you need. The Demo animates the transformation by rotating, scaling, and translating using createMatrix then uses toWorld to convert the mouse coordinates to the world space.
// the demo function
var demo = function(){
/** fullScreenCanvas.js begin **/
// create a full document canvas on top
var canvas = (function(){
var canvas = document.getElementById("canv");
if(canvas !== null){
document.body.removeChild(canvas);
}
// creates a blank image with 2d context
canvas = document.createElement("canvas");
canvas.id = "canv";
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
canvas.style.position = "absolute";
canvas.style.top = "0px";
canvas.style.left = "0px";
canvas.style.zIndex = 1000;
canvas.ctx = canvas.getContext("2d");
document.body.appendChild(canvas);
return canvas;
})();
var ctx = canvas.ctx;
/** fullScreenCanvas.js end **/
/** MouseFull.js begin **/
// get the mouse data . This is a generic mouse handler I use so a little over kill for this example
var canvasMouseCallBack = undefined; // if needed
var mouse = (function(){
var mouse = {
x : 0, y : 0, w : 0, alt : false, shift : false, ctrl : false,
interfaceId : 0, buttonLastRaw : 0, buttonRaw : 0,
over : false, // mouse is over the element
bm : [1, 2, 4, 6, 5, 3], // masks for setting and clearing button raw bits;
getInterfaceId : function () { return this.interfaceId++; }, // For UI functions
startMouse:undefined,
};
function mouseMove(e) {
var t = e.type, m = mouse;
m.x = e.offsetX; m.y = e.offsetY;
if (m.x === undefined) { m.x = e.clientX; m.y = e.clientY; }
m.alt = e.altKey;m.shift = e.shiftKey;m.ctrl = e.ctrlKey;
if (t === "mousedown") { m.buttonRaw |= m.bm[e.which-1];
} else if (t === "mouseup") { m.buttonRaw &= m.bm[e.which + 2];
} else if (t === "mouseout") { m.buttonRaw = 0; m.over = false;
} else if (t === "mouseover") { m.over = true;
} else if (t === "mousewheel") { m.w = e.wheelDelta;
} else if (t === "DOMMouseScroll") { m.w = -e.detail;}
if (canvasMouseCallBack) { canvasMouseCallBack(m.x, m.y); }
e.preventDefault();
}
function startMouse(element){
if(element === undefined){
element = document;
}
"mousemove,mousedown,mouseup,mouseout,mouseover,mousewheel,DOMMouseScroll".split(",").forEach(
function(n){element.addEventListener(n, mouseMove);});
element.addEventListener("contextmenu", function (e) {e.preventDefault();}, false);
}
mouse.mouseStart = startMouse;
return mouse;
})();
if(typeof canvas === "undefined"){
mouse.mouseStart();
}else{
mouse.mouseStart(canvas);
}
/** MouseFull.js end **/
// some stuff to draw a grid
var gridStart= -(canvas.width/10)*4;
var gridEnd = (canvas.width/10)*14;
var gridStepMajor = canvas.width/10;
var gridStepMinor = canvas.width/20;
var minorCol = "#999";
var majorCol = "#000";
var minorWidth = 1;
var majorWidth = 3;
// some stuf to animate the transformation
var timer = 0;
var timerStep = 0.01;
//----------------------------------------------------------------------------
// the code from the answer
var matrix = [1, 0, 0, 1, 0, 0]; // normal matrix
var invMatrix = [1, 0, 0, 1]; // inverse matrix
function createMatrix(x, y, scale, rotate){
var m = matrix; // just to make it easier to type and read
var im = invMatrix; // just to make it easier to type and read
// create the scale and rotation part of the matrix
m[3] = m[0] = Math.cos(rotate) * scale;
m[2] = -(m[1] = Math.sin(rotate) * scale);
// translation
m[4] = x;
m[5] = y;
// calculate the inverse transformation
// first get the cross product of x axis and y axis
cross = m[0] * m[3] - m[1] * m[2];
// now get the inverted axies
im[0] = m[3] / cross;
im[1] = -m[1] / cross;
im[2] = -m[2] / cross;
im[3] = m[0] / cross;
}
// function to transform to world space
function toWorld(x,y){
var xx, yy, m;
m = invMatrix;
xx = x - matrix[4];
yy = y - matrix[5];
return {
x: xx * m[0] + yy * m[2] ,
y: xx * m[1] + yy * m[3]
}
}
//----------------------------------------------------------------------------
// center of canvas
var cw = canvas.width / 2;
var ch = canvas.height / 2;
// the main loop
function update(){
var i,x,y,s;
ctx.setTransform(1, 0, 0, 1, 0, 0); // reset the transform so we can clear
ctx.clearRect(0, 0, canvas.width, canvas.height); // clear the canvas
// animate the transformation
timer += timerStep;
x = Math.cos(timer) * gridStepMajor * 5 + cw; // position
y = Math.sin(timer) * gridStepMajor * 5 + ch;
s = Math.sin(timer/1.2) + 1.5; // scale
//----------------------------------------------------------------------
// create the matrix at x,y scale = s and rotation time/3
createMatrix(x,y,s,timer/3);
// use the created matrix to set the transformation
var m = matrix;
ctx.setTransform(m[0], m[1], m[2], m[3], m[4], m[5]);
//----------------------------------------------------------------------------
//draw a grid
ctx.lineWidth = 2;
ctx.beginPath();
ctx.strokeStyle = majorCol ;
ctx.lineWidth = majorWidth;
for(i = gridStart; i <= gridEnd; i+= gridStepMajor){
ctx.moveTo(gridStart, i);
ctx.lineTo(gridEnd, i);
ctx.moveTo(i, gridStart);
ctx.lineTo(i, gridEnd);
}
ctx.stroke();
ctx.strokeStyle = minorCol ;
ctx.lineWidth = minorWidth;
for(i = gridStart+gridStepMinor; i < gridEnd; i+= gridStepMinor){
ctx.moveTo(gridStart, i);
ctx.lineTo(gridEnd, i);
ctx.moveTo(i, gridStart);
ctx.lineTo(i, gridEnd);
}
ctx.stroke();
//---------------------------------------------------------------------
// get the mouse world coordinates
var mouseWorldPos = toWorld(mouse.x, mouse.y);
//---------------------------------------------------------------------
// marke the location with a cross and a circle;
ctx.strokeStyle = "red";
ctx.lineWidth = 3;
ctx.beginPath();
ctx.moveTo(mouseWorldPos.x - gridStepMajor, mouseWorldPos.y)
ctx.lineTo(mouseWorldPos.x + gridStepMajor, mouseWorldPos.y)
ctx.moveTo(mouseWorldPos.x, mouseWorldPos.y - gridStepMajor)
ctx.lineTo(mouseWorldPos.x, mouseWorldPos.y + gridStepMajor)
ctx.stroke();
ctx.fillStyle = "red";
ctx.strokeStyle = "yellow";
ctx.lineWidth = 4;
ctx.beginPath();
ctx.arc(mouseWorldPos.x, mouseWorldPos.y, 6, 0, Math.PI*2);
ctx.fill();
ctx.stroke();
ctx.fillStyle = "Blue";
ctx.setTransform(1,0,0,1,0,0);
ctx.font = "18px Arial";
var str = "Mouse canvas X: "+ mouse.x + " Y: " + mouse.y;
ctx.fillText(str , 10 ,18);
var str = "Mouse world X: "+ mouseWorldPos.x.toFixed(2) + " Y: " + mouseWorldPos.y.toFixed(2);
ctx.fillText(str , 10 ,36);
// if not over request a new animtion frame
if(!endItAll){
requestAnimationFrame(update);
}else{
// if done remove the canvas
var can = document.getElementById("canv");
if(can !== null){
document.body.removeChild(can);
}
// flag that we are ready to start again
endItAll = false;
}
}
update(); // start the animation
}
// Flag to indicate that the current execution should shut down
var endItAll = false;
// resizes but waits for the current running animnation to shut down
function resizeIt(){
endItAll = true;
function waitForIt(){
if(!endItAll){
demo();
}else{
setTimeout(waitForIt, 100);
}
}
setTimeout(waitForIt, 100);
}
// starts the demo
demo();
// listen to resize events and resize canvas if needed
window.addEventListener("resize",resizeIt)

Go step by step :
Find the coordinates of the mouse on the canvas:
var rect = canvas.getBoundingClientRect();
var xMouse = event.clientX - rect.left;
var yMouse = event.clientY - rect.top;
Normalize those coordinates so they are in [0;1] :
var relX = xMouse / canvas.width;
var relY = yMouse / canvas.height;
now say you view is defined by a rect called... well... viewRect, the position of the mouse in the view is :
var viewX = viewRect.left + relX*(viewRect.right-viewRect.left);
var viewY = viewRect.top + relY*(viewRect.bottom-viewRect.top);
When you launch your app your rect is 0,0,canvasWidth, canvasHeight.
When you click, you have to adjust your rect.
If clicking means zooming by zFactor at viewX, viewY, code will look like :
var newWidth = viewRect.width/zFactor;
var newHeight = viewRect.height/zFactor;
viewRect.left = viewX - newWidth/2;
viewRect.right = viewX + newWidth/2;
viewRect.top = viewY - newHeight/2;
viewRect.bottom = viewY + newHeight/2;
your draw method should look like :
context.save();
context.translate((viewRect.left+viewRect.right )/ 2, ...) ;
var scaleFactor = (viewRect.right+viewRect.left ) / canvasWidth;
context.scale(scaleFactor, scaleFactor);
... draw
context.restore();

Instead of keeping track of the various transformations, I inquired of the canvas for the current transform:
function mouseUp(canvas, event) {
const rect = canvas.getBoundingClientRect();
const transform = graphics.getTransform();
const canvasX = (event.clientX - rect.left - transform.e) / transform.a;
const canvasY = (event.clientY - rect.top - transform.f) / transform.d;
The doesn't deal with skew, but it gives a general idea of the approach I'm using.

Line of sight from point

Need to create simple line of sight from point. Length of this line would be adapt to the size of canvas. If line directed to any object (circle, rectangle etc) it must be interrupted after this. I don't know exactly how to describe this, but behavior should be something like this. It's like laser aim in video-games.
Demo jsfiddle. Target line has red color. I think that line must have dynamic length depending on where I will direct it.
var canvas = document.querySelector("canvas");
canvas.width = 500;
canvas.height = 300;
var ctx = canvas.getContext("2d"),
line = {
x1: 190, y1: 170,
x2: 0, y2: 0,
x3: 0, y3: 0
};
var length = 100;
var circle = {
x: 400,
y: 70
};
window.onmousemove = function(e) {
//get correct mouse pos
var rect = ctx.canvas.getBoundingClientRect(),
x = e.clientX - rect.left,
y = e.clientY - rect.top;
// calc line angle
var dx = x - line.x1,
dy = y - line.y1,
angle = Math.atan2(dy, dx);
//Then render the line using 100 pixel radius:
line.x2 = line.x1 - length * Math.cos(angle);
line.y2 = line.y1 - length * Math.sin(angle);
line.x3 = line.x1 + canvas.width * Math.cos(angle);
line.y3 = line.y1 + canvas.width * Math.sin(angle);
// render
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.beginPath();
ctx.moveTo(line.x1, line.y1);
ctx.lineTo(line.x2, line.y2);
ctx.strokeStyle = '#333';
ctx.stroke();
ctx.beginPath();
ctx.moveTo(line.x1, line.y1);
ctx.lineTo(line.x3, line.y3);
ctx.strokeStyle = 'red';
ctx.stroke();
ctx.beginPath();
ctx.arc(circle.x, circle.y, 20, 0, Math.PI * 2, true);
ctx.fillStyle = '#333';
ctx.fill();
}
<canvas></canvas>

Ray casting
The given answer is a good answer but this problem is better suited to a ray casting like solution where we are only interested in the distance to an intercept rather than the actual point of interception. We only need one point per cast ray so not calculating points will reduce the math and hence the CPU load giving more rays and objects per second.
A ray is a point that defines the start and a normalised vector that represents the direction of the ray. Because the ray uses a normalised vector that is a unit length many calculations are simplified because 1 * anything changes nothing.
Also the problem is about looking for the closest intercept so the intercept functions return a distance from the ray's origin. If no intercept is found then Infinity is returned to allow a valid distance comparison to be made. Every number is less than Infinity.
A nice feature of JavaScript is that it allows divide by zero and returns Infinity if that happens, this further reduces the complexity of the solution. Also if the intercept finds a negative intercept that means the object is behind that raycast origin and thus will return infinity as well.
So first let's define our objects by creating functions to make them. They are all ad hoc objects.
The Ray
// Ad Hoc method for ray to set the direction vector
var updateRayDir = function(dir){
this.nx = Math.cos(dir);
this.ny = Math.sin(dir);
return this;
}
// Creates a ray objects from
// x,y start location
// dir the direction in radians
// len the rays length
var createRay = function(x,y,dir,len){
return ({
x : x,
y : y,
len : len,
setDir : updateRayDir, // add function to set direction
}).setDir(dir);
}
A circle
// returns a circle object
// x,y is the center
// radius is the you know what..
// Note r2 is radius squared if you change the radius remember to set r2 as well
var createCircle = function(x , y, radius){
return {
x : x,
y : y,
rayDist : rayDist2Circle, // add ray cast method
radius : radius,
r2 : radius * radius, // ray caster needs square of radius may as well do it here
};
}
A wall
Note I changed the wall code in the demo
// Ad Hoc function to change the wall position
// x1,y1 are the start coords
// x2,y2 are the end coords
changeWallPosition = function(x1, y1, x2, y2){
this.x = x1;
this.y = y1;
this.vx = x2 - x1;
this.vy = y2 - y1;
this.len = Math.hypot(this.vx,this.vy);
this.nx = this.vx / this.len;
this.ny = this.vy / this.len;
return this;
}
// returns a wall object
// x1,y1 are the star coords
// x2,y2 are the end coords
var createWall = function(x1, y1, x2, y2){
return({
x : x1, y : y1,
vx : x2 - x1,
vy : y2 - y1,
rayDist : rayDist2Wall, // add ray cast method
setPos : changeWallPosition,
}).setPos(x1, y1, x2, y2);
}
So those are the objects, they can be static or moving through the circle should have a setRadius function because I have added a property that holds the square of the radius but I will leave that up to you if you use that code.
Now the intercept functions.
Ray Intercepts
The stuff that matters. In the demo these functions are bound to the objects so that the ray casting code need not have to know what type of object it is checking.
Distance to circle.
// Self evident
// returns a distance or infinity if no valid solution
var rayDist2Circle = function(ray){
var vcx, vcy, v;
vcx = ray.x - this.x; // vector from ray to circle
vcy = ray.y - this.y;
v = -2 * (vcx * ray.nx + vcy * ray.ny);
v -= Math.sqrt(v * v - 4 * (vcx * vcx + vcy * vcy - this.r2)); // this.r2 is the radius squared
// If there is no solution then Math.sqrt returns NaN we should return Infinity
// Not interested in intercepts in the negative direction so return infinity
return isNaN(v) || v < 0 ? Infinity : v / 2;
}
Distance to wall
// returns the distance to the wall
// if no valid solution then return Infinity
var rayDist2Wall = function(ray){
var x,y,u;
rWCross = ray.nx * this.ny - ray.ny * this.nx;
if(!rWCross) { return Infinity; } // Not really needed.
x = ray.x - this.x; // vector from ray to wall start
y = ray.y - this.y;
u = (ray.nx * y - ray.ny * x) / rWCross; // unit distance along normalised wall
// does the ray hit the wall segment
if(u < 0 || u > this.len){ return Infinity;} /// no
// as we use the wall normal and ray normal the unit distance is the same as the
u = (this.nx * y - this.ny * x) / rWCross;
return u < 0 ? Infinity : u; // if behind ray return Infinity else the dist
}
That covers the objects. If you need to have a circle that is inside out (you want the inside surface then change the second last line of the circle ray function to v += rather than v -=
The ray casting
Now it is just a matter of iterating all the objects against the ray and keeping the distant to the closest object. Set the ray to that distance and you are done.
// Does a ray cast.
// ray the ray to cast
// objects an array of objects
var castRay = function(ray,objects)
var i,minDist;
minDist = ray.len; // set the min dist to the rays length
i = objects.length; // number of objects to check
while(i > 0){
i -= 1;
minDist = Math.min(objects[i].rayDist(ray),minDist);
}
ray.len = minDist;
}
A demo
And a demo of all the above in action. THere are some minor changes (drawing). The important stuff is the two intercept functions. The demo creates a random scene each time it is resized and cast 16 rays from the mouse position. I can see in your code you know how to get the direction of a line so I made the demo show how to cast multiple rays that you most likely will end up doing
const COLOUR = "BLACK";
const RAY_COLOUR = "RED";
const LINE_WIDTH = 4;
const RAY_LINE_WIDTH = 2;
const OBJ_COUNT = 20; // number of object in the scene;
const NUMBER_RAYS = 16; // number of rays
const RAY_DIR_SPACING = Math.PI / (NUMBER_RAYS / 2);
const RAY_ROTATE_SPEED = Math.PI * 2 / 31000;
if(typeof Math.hypot === "undefined"){ // poly fill for Math.hypot
Math.hypot = function(x, y){
return Math.sqrt(x * x + y * y);
}
}
var ctx, canvas, objects, ray, w, h, mouse, rand, ray, rayMaxLen, screenDiagonal;
// create a canvas and add to the dom
var canvas = document.createElement("canvas");
canvas.width = w = window.innerWidth;
canvas.height = h = window.innerHeight;
canvas.style.position = "absolute";
canvas.style.left = "0px";
canvas.style.top = "0px";
document.body.appendChild(canvas);
// objects to ray cast
objects = [];
// mouse object
mouse = {x :0, y: 0};
//========================================================================
// random helper
rand = function(min, max){
return Math.random() * (max - min) + min;
}
//========================================================================
// Ad Hoc draw line method
// col is the stroke style
// width is the storke width
var drawLine = function(col,width){
ctx.strokeStyle = col;
ctx.lineWidth = width;
ctx.beginPath();
ctx.moveTo(this.x,this.y);
ctx.lineTo(this.x + this.nx * this.len, this.y + this.ny * this.len);
ctx.stroke();
}
//========================================================================
// Ad Hoc draw circle method
// col is the stroke style
// width is the storke width
var drawCircle = function(col,width){
ctx.strokeStyle = col;
ctx.lineWidth = width;
ctx.beginPath();
ctx.arc(this.x , this.y, this.radius, 0 , Math.PI * 2);
ctx.stroke();
}
//========================================================================
// Ad Hoc method for ray to set the direction vector
var updateRayDir = function(dir){
this.nx = Math.cos(dir);
this.ny = Math.sin(dir);
return this;
}
//========================================================================
// Creates a ray objects from
// x,y start location
// dir the direction in radians
// len the rays length
var createRay = function(x,y,dir,len){
return ({
x : x,
y : y,
len : len,
draw : drawLine,
setDir : updateRayDir, // add function to set direction
}).setDir(dir);
}
//========================================================================
// returns a circle object
// x,y is the center
// radius is the you know what..
// Note r2 is radius squared if you change the radius remember to set r2 as well
var createCircle = function(x , y, radius){
return {
x : x,
y : y,
draw : drawCircle, // draw function
rayDist : rayDist2Circle, // add ray cast method
radius : radius,
r2 : radius * radius, // ray caster needs square of radius may as well do it here
};
}
//========================================================================
// Ad Hoc function to change the wall position
// x1,y1 are the start coords
// x2,y2 are the end coords
changeWallPosition = function(x1, y1, len, dir){
this.x = x1;
this.y = y1;
this.len = len;
this.nx = Math.cos(dir);
this.ny = Math.sin(dir);
return this;
}
//========================================================================
// returns a wall object
// x1,y1 are the star coords
// len is the length
// dir is the direction
var createWall = function(x1, y1, len, dir){
return({
x : x1, y : y1,
rayDist : rayDist2Wall, // add ray cast method
draw : drawLine,
setPos : changeWallPosition,
}).setPos(x1, y1, len, dir);
}
//========================================================================
// Self evident
// returns a distance or infinity if no valid solution
var rayDist2Circle = function(ray){
var vcx, vcy, v;
vcx = ray.x - this.x; // vector from ray to circle
vcy = ray.y - this.y;
v = -2 * (vcx * ray.nx + vcy * ray.ny);
v -= Math.sqrt(v * v - 4 * (vcx * vcx + vcy * vcy - this.r2)); // this.r2 is the radius squared
// If there is no solution then Math.sqrt returns NaN we should return Infinity
// Not interested in intercepts in the negative direction so return infinity
return isNaN(v) || v < 0 ? Infinity : v / 2;
}
//========================================================================
// returns the distance to the wall
// if no valid solution then return Infinity
var rayDist2Wall = function(ray){
var x,y,u;
rWCross = ray.nx * this.ny - ray.ny * this.nx;
if(!rWCross) { return Infinity; } // Not really needed.
x = ray.x - this.x; // vector from ray to wall start
y = ray.y - this.y;
u = (ray.nx * y - ray.ny * x) / rWCross; // unit distance along normal of wall
// does the ray hit the wall segment
if(u < 0 || u > this.len){ return Infinity;} /// no
// as we use the wall normal and ray normal the unit distance is the same as the
u = (this.nx * y - this.ny * x) / rWCross;
return u < 0 ? Infinity : u; // if behind ray return Infinity else the dist
}
//========================================================================
// does a ray cast
// ray the ray to cast
// objects an array of objects
var castRay = function(ray,objects){
var i,minDist;
minDist = ray.len; // set the min dist to the rays length
i = objects.length; // number of objects to check
while(i > 0){
i -= 1;
minDist = Math.min(objects[i].rayDist(ray), minDist);
}
ray.len = minDist;
}
//========================================================================
// Draws all objects
// objects an array of objects
var drawObjects = function(objects){
var i = objects.length; // number of objects to check
while(i > 0){
objects[--i].draw(COLOUR, LINE_WIDTH);
}
}
//========================================================================
// called on start and resize
// creats a new scene each time
// fits the canvas to the avalible realestate
function reMakeAll(){
w = canvas.width = window.innerWidth;
h = canvas.height = window.innerHeight;
ctx = canvas.getContext("2d");
screenDiagonal = Math.hypot(window.innerWidth,window.innerHeight);
if(ray === undefined){
ray = createRay(0,0,0,screenDiagonal);
}
objects.length = 0;
var i = OBJ_COUNT;
while( i > 0 ){
if(Math.random() < 0.5){ // half circles half walls
objects.push(createWall(rand(0, w), rand(0, h), rand(screenDiagonal * 0.1, screenDiagonal * 0.2), rand(0, Math.PI * 2)));
}else{
objects.push(createCircle(rand(0, w), rand(0, h), rand(screenDiagonal * 0.02, screenDiagonal * 0.05)));
}
i -= 1;
}
}
//========================================================================
function mouseMoveEvent(event){
mouse.x = event.clientX;
mouse.y = event.clientY;
}
//========================================================================
// updates all that is needed when needed
function updateAll(time){
var i;
ctx.clearRect(0,0,w,h);
ray.x = mouse.x;
ray.y = mouse.y;
drawObjects(objects);
i = 0;
while(i < NUMBER_RAYS){
ray.setDir(i * RAY_DIR_SPACING + time * RAY_ROTATE_SPEED);
ray.len = screenDiagonal;
castRay(ray,objects);
ray.draw(RAY_COLOUR, RAY_LINE_WIDTH);
i ++;
}
requestAnimationFrame(updateAll);
}
// add listeners
window.addEventListener("resize",reMakeAll);
canvas.addEventListener("mousemove",mouseMoveEvent);
// set it all up
reMakeAll();
// start the ball rolling
requestAnimationFrame(updateAll);
An alternative use of above draws a polygon using the end points of the cast rays can be seen at codepen

For this you would need a line to circle intersection algorithm for the balls as well as line to line intersection for the walls.
For the ball you can use this function - I made this to return arrays being empty if no intersection, one point if tangent or two points if secant.
Simply feed it start of line, line of sight end-point as well as the ball's center position and radius. In your case you will probably only need the first point:
function lineIntersectsCircle(x1, y1, x2, y2, cx, cy, r) {
x1 -= cx;
y1 -= cy;
x2 -= cx;
y2 -= cy;
// solve quadrant
var a = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1),
b = 2 * ((x2 - x1) * x1 + (y2 - y1) * y1),
c = x1 * x1 + y1 * y1 - r * r,
d = b * b - 4 * a * c,
dq, p1, p2, t1, t2;
if (d <= 0 || !a) return [];
dq = Math.sqrt(d);
t1 = (-b - dq) / (2 * a);
t2 = (-b + dq) / (2 * a);
// calculate actual intersection points
if (t1 >= 0 && t1 <= 1)
p1 = {
x: x1 + t1 * (x2 - x1) + cx,
y: y1 + t1 * (y2 - y1) + cy
};
if (t2 >= 0 && t2 <= 1)
p2 = {
x: x1 + t2 * (x2 - x1) + cx,
y: y1 + t2 * (y2 - y1) + cy
};
return p1 && p2 ? [p1, p2] : p1 ? [p1] : [p2]
};
Then for the walls you would need a line to line intersection - define one line for each side of the rectangle. If there is line overlap you may get hit for two intersection, just ignore the second.
This will return a single point for the intersection or null if no intersection:
function getLineIntersection(p0x, p0y, p1x, p1y, p2x, p2y, p3x, p3y) {
var d1x = p1x - p0x,
d1y = p1y - p0y,
d2x = p3x - p2x,
d2y = p3y - p2y,
d = d1x * d2y - d2x * d1y,
px, py, s, t;
if (Math.abs(d) < 1e-14) return null;
px = p0x - p2x;
py = p0y - p2y;
s = (d1x * py - d1y * px) / d;
if (s >= 0 && s <= 1) {
t = (d2x * py - d2y * px) / d;
if (t >= 0 && t <= 1) {
return {
x: p0x + (t * d1x),
y: p0y + (t * d1y)
}
}
}
return null
}
Then just iterate with the line through the ball array, if no hit, iterate through the wall array.
Modified fiddle
To utilize these you will have to run the line through these each time it is moved (or per frame update).
Tip: You can make the function recursive so that you can find the intersection point, calculate reflected vector based on the hit angle, then find next intersection for n number of times (or total length the shot can move) using the last intersecting point and new angle as start of next line. This way you can build the path the shot will follow.
var canvas = document.querySelector("canvas");
canvas.width = 500;
canvas.height = 300;
var ctx = canvas.getContext("2d"),
line = {
x1: 190, y1: 170,
x2: 0, y2: 0,
x3: 0, y3: 0
};
var length = 100;
var circle = {
x: 400,
y: 70
};
var wall = {
x1: 440, y1: 0,
x2: 440, y2: 100
};
window.onmousemove = function(e) {
//get correct mouse pos
var rect = ctx.canvas.getBoundingClientRect(),
x = e.clientX - rect.left,
y = e.clientY - rect.top;
// calc line angle
var dx = x - line.x1,
dy = y - line.y1,
angle = Math.atan2(dy, dx);
//Then render the line using length as pixel radius:
line.x2 = line.x1 - length * Math.cos(angle);
line.y2 = line.y1 - length * Math.sin(angle);
line.x3 = line.x1 + canvas.width * Math.cos(angle);
line.y3 = line.y1 + canvas.width * Math.sin(angle);
// does it intersect?
var pts = lineIntersectsCircle(line.x1, line.y1, line.x3, line.y3, circle.x, circle.y, 20);
if (pts.length) {
line.x3 = pts[0].x;
line.y3 = pts[0].y
}
else {
pts = getLineIntersection(line.x1, line.y1, line.x3, line.y3, wall.x1, wall.y1, wall.x2, wall.y2);
if (pts) {
line.x3 = pts.x;
line.y3 = pts.y
}
}
// render
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.beginPath();
ctx.moveTo(line.x1, line.y1);
ctx.lineTo(line.x2, line.y2);
ctx.strokeStyle = '#333';
ctx.stroke();
ctx.beginPath();
ctx.moveTo(line.x1, line.y1);
ctx.lineTo(line.x3, line.y3);
ctx.strokeStyle = 'red';
ctx.stroke();
ctx.beginPath();
ctx.arc(circle.x, circle.y, 20, 0, Math.PI * 2, true);
ctx.fillStyle = '#333';
ctx.fill();
// render example wall:
ctx.fillRect(wall.x1, wall.y1, 4, wall.y2-wall.y1);
}
function lineIntersectsCircle(x1, y1, x2, y2, cx, cy, r) {
x1 -= cx;
y1 -= cy;
x2 -= cx;
y2 -= cy;
// solve quadrant
var a = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1),
b = 2 * ((x2 - x1) * x1 + (y2 - y1) * y1),
c = x1 * x1 + y1 * y1 - r * r,
d = b * b - 4 * a * c,
dq, p1, p2, t1, t2;
if (d <= 0 || !a) return [];
dq = Math.sqrt(d);
t1 = (-b - dq) / (2 * a);
t2 = (-b + dq) / (2 * a);
// calculate actual intersection points
if (t1 >= 0 && t1 <= 1)
p1 = {
x: x1 + t1 * (x2 - x1) + cx,
y: y1 + t1 * (y2 - y1) + cy
};
if (t2 >= 0 && t2 <= 1)
p2 = {
x: x1 + t2 * (x2 - x1) + cx,
y: y1 + t2 * (y2 - y1) + cy
};
return p1 && p2 ? [p1, p2] : p1 ? [p1] : [p2]
};
function getLineIntersection(p0x, p0y, p1x, p1y, p2x, p2y, p3x, p3y) {
var d1x = p1x - p0x,
d1y = p1y - p0y,
d2x = p3x - p2x,
d2y = p3y - p2y,
d = d1x * d2y - d2x * d1y,
px, py, s, t;
if (Math.abs(d) < 1e-14) return null;
px = p0x - p2x;
py = p0y - p2y;
s = (d1x * py - d1y * px) / d;
if (s >= 0 && s <= 1) {
t = (d2x * py - d2y * px) / d;
if (t >= 0 && t <= 1) {
return {
x: p0x + (t * d1x),
y: p0y + (t * d1y)
}
}
}
return null
}
<canvas></canvas>

I don't have enough reputation to add this as a comment to Blindman67's solution, so i have to resort to adding this as an answer.
Blindman67's answer is great, but i needed support for polygons as well.
I am no math wizard so there may be a much better solution for polygons than this, but what i did was loop over all pairs of points from a polygon (so all sides of a polygon, really) and treat them as walls based on the code from Blindman67, then check the ray distance in the new rayDist2Polygon:
var rayDist2Polygon = function(ray){
let u,lineU;
const polLength = this.points.length;
const startX = this.x;
const startY = this.y;
// Loop over all lines of the polygon
for (i = 0; i < polLength; i++) {
const nextPoint = i === polLength - 1 ? this.points[0] : this.points[i + 1];
const x1 = startX + this.points[i].x;
const x2 = startX + nextPoint.x;
const y1 = startY + this.points[i].y;
const y2 = startY + nextPoint.y;
this.setupWall(x1, y1, x2, y2);
lineU = rayDist2Wall.bind(this)(ray);
if (!u) {
// If it's the first hit, assign it to `u`
u = lineU;
} else if (lineU < u) {
// If the current hit is smaller than anything we have so far, then this is the closest one, assign it to `u`
u = lineU;
}
}
// Reset positions after running this.setupWall;
this.x = startX;
this.y = startY;
return (!u || u < 0) ? Infinity : u; // if behind ray return Infinity else the dist
}
Then used the same logic to also support squares by converting a square's dimension/shape to points.
You can view it below, or fiddle with it at my codepen.
// Forked from https://stackoverflow.com/a/36566360/16956030
// All credits go to Blindman67
// All i did was add support for Polygons and Squares based on code from
// Blindman67, by treating each side of a polyon/square as a line/wall,
// then loop over each side and get the smallest result in rayDist2Polygon.
// I'm no math wizard and there may be a much better solution for these shapes,
// but this'll do for now.
console.clear();
const COLOUR = "BLACK";
const RAY_COLOUR = "RED";
const LINE_WIDTH = 4;
const RAY_LINE_WIDTH = 2;
const OBJ_COUNT = 20; // number of object in the scene;
const NUMBER_RAYS = 16; // number of rays
const RAY_DIR_SPACING = Math.PI / (NUMBER_RAYS / 2);
const RAY_ROTATE_SPEED = Math.PI * 2 / 31000;
if(typeof Math.hypot === "undefined"){ // poly fill for Math.hypot
Math.hypot = function(x, y){
return Math.sqrt(x * x + y * y);
}
}
var ctx, canvas, objects, ray, w, h, mouse, rand, ray, rayMaxLen, screenDiagonal;
// create a canvas and add to the dom
var canvas = document.createElement("canvas");
canvas.width = w = window.innerWidth;
canvas.height = h = window.innerHeight;
canvas.style.position = "absolute";
canvas.style.left = "0px";
canvas.style.top = "0px";
document.body.appendChild(canvas);
// objects to ray cast
objects = [];
// mouse object
mouse = {x :0, y: 0};
//========================================================================
// random helper
rand = function(min, max){
return Math.random() * (max - min) + min;
}
//========================================================================
// Ad Hoc draw line method
// col is the stroke style
// width is the storke width
var drawLine = function(col,width){
ctx.strokeStyle = col;
ctx.lineWidth = width;
ctx.beginPath();
ctx.moveTo(this.x,this.y);
ctx.lineTo(this.x + this.nx * this.len, this.y + this.ny * this.len);
ctx.stroke();
}
//========================================================================
// Ad Hoc draw circle method
// col is the stroke style
// width is the storke width
var drawCircle = function(col,width){
ctx.strokeStyle = col;
ctx.lineWidth = width;
ctx.beginPath();
ctx.arc(this.x , this.y, this.radius, 0 , Math.PI * 2);
ctx.stroke();
}
//========================================================================
// Ad Hoc draw square method
var drawSquare = function(){
ctx.beginPath();
ctx.rect(this.x, this.y, this.width, this.height);
ctx.stroke();
// Create array of points like a polygon based on the position & dimensions
// from this square, necessary for rayDist2Polygon
this.points = [
{ x: 0, y: 0},
{ x: this.width, y: 0},
{ x: this.width, y: this.height},
{ x: 0, y: this.height}
];
}
//========================================================================
// Ad Hoc draw [poligon] method
var drawPolygon = function(){
ctx.beginPath();
ctx.moveTo(this.x,this.y);
var polLength = this.points.length;
for(var i=0; i < polLength; ++i) {
ctx.lineTo(this.x + this.points[i].x, this.y + this.points[i].y);
}
ctx.closePath();
ctx.stroke();
}
//========================================================================
// Ad Hoc method for ray to set the direction vector
var updateRayDir = function(dir){
this.nx = Math.cos(dir);
this.ny = Math.sin(dir);
return this;
}
//========================================================================
// Creates a ray objects from
// x,y start location
// dir the direction in radians
// len the rays length
var createRay = function(x,y,dir,len){
return ({
x : x,
y : y,
len : len,
draw : drawLine,
setDir : updateRayDir, // add function to set direction
}).setDir(dir);
}
//========================================================================
// returns a circle object
// x,y is the center
// radius is the you know what..
// Note r2 is radius squared if you change the radius remember to set r2 as well
var createCircle = function(x , y, radius){
return {
x : x,
y : y,
draw : drawCircle, // draw function
rayDist : rayDist2Circle, // add ray cast method
radius : radius,
r2 : radius * radius, // ray caster needs square of radius may as well do it here
};
}
// Ad Hoc function to set the wall information
// x1,y1 are the start coords
// x2,y2 are the end coords
setupWallInformation = function(x1, y1, x2, y2){
this.x = x1;
this.y = y1;
this.vx = x2 - x1;
this.vy = y2 - y1;
this.len = Math.hypot(this.vx,this.vy);
this.nx = this.vx / this.len;
this.ny = this.vy / this.len;
return this;
}
//========================================================================
// returns a polygon object
// x,y are the start coords
// In this example the polygon always has the same shape
var createPolygon = function(x , y){
return {
x : x,
y : y,
points: [
{ x: 0, y: 0},
{ x: 100, y: 50},
{ x: 50, y: 100},
{ x: 0, y: 90}
],
draw : drawPolygon, // draw function
setupWall : setupWallInformation,
rayDist : rayDist2Polygon, // add ray cast method
};
}
//========================================================================
// returns a square object
// x,y are the start coords
// In this example the polygon always has the same shape
var createSquare = function(x , y, width, height){
return {
x : x,
y : y,
width: width,
height: height,
draw : drawSquare, // draw function
setupWall : setupWallInformation,
rayDist : rayDist2Polygon, // add ray cast method
};
}
//========================================================================
// Ad Hoc function to change the wall position
// x1,y1 are the start coords
// x2,y2 are the end coords
changeWallPosition = function(x1, y1, len, dir){
this.x = x1;
this.y = y1;
this.len = len;
this.nx = Math.cos(dir);
this.ny = Math.sin(dir);
return this;
}
//========================================================================
// returns a wall object
// x1,y1 are the star coords
// len is the length
// dir is the direction
var createWall = function(x1, y1, len, dir){
return({
x : x1, y : y1,
rayDist : rayDist2Wall, // add ray cast method
draw : drawLine,
setPos : changeWallPosition,
}).setPos(x1, y1, len, dir);
}
//========================================================================
// Self evident
// returns a distance or infinity if no valid solution
var rayDist2Circle = function(ray){
var vcx, vcy, v;
vcx = ray.x - this.x; // vector from ray to circle
vcy = ray.y - this.y;
v = -2 * (vcx * ray.nx + vcy * ray.ny);
v -= Math.sqrt(v * v - 4 * (vcx * vcx + vcy * vcy - this.r2)); // this.r2 is the radius squared
// If there is no solution then Math.sqrt returns NaN we should return Infinity
// Not interested in intercepts in the negative direction so return infinity
return isNaN(v) || v < 0 ? Infinity : v / 2;
}
//========================================================================
// returns the distance to the wall
// if no valid solution then return Infinity
var rayDist2Wall = function(ray){
var x,y,u;
rWCross = ray.nx * this.ny - ray.ny * this.nx;
if(!rWCross) { return Infinity; } // Not really needed.
x = ray.x - this.x; // vector from ray to wall start
y = ray.y - this.y;
u = (ray.nx * y - ray.ny * x) / rWCross; // unit distance along normal of wall
// does the ray hit the wall segment
if(u < 0 || u > this.len){ return Infinity;} /// no
// as we use the wall normal and ray normal the unit distance is the same as the
u = (this.nx * y - this.ny * x) / rWCross;
return u < 0 ? Infinity : u; // if behind ray return Infinity else the dist
}
//========================================================================
// returns the distance to the polygon
// if no valid solution then return Infinity
var rayDist2Polygon = function(ray){
let u,lineU;
const polLength = this.points.length;
const startX = this.x;
const startY = this.y;
// Loop over all lines of the polygon
for (i = 0; i < polLength; i++) {
const nextPoint = i === polLength - 1 ? this.points[0] : this.points[i + 1];
const x1 = startX + this.points[i].x;
const x2 = startX + nextPoint.x;
const y1 = startY + this.points[i].y;
const y2 = startY + nextPoint.y;
this.setupWall(x1, y1, x2, y2);
lineU = rayDist2Wall.bind(this)(ray);
if (!u) {
// If it's the first hit, assign it to `u`
u = lineU;
} else if (lineU < u) {
// If the current hit is smaller than anything we have so far, then this is the closest one, assign it to `u`
u = lineU;
}
}
// Reset positions after running this.setupWall;
this.x = startX;
this.y = startY;
return (!u || u < 0) ? Infinity : u; // if behind ray return Infinity else the dist
}
//========================================================================
// does a ray cast
// ray the ray to cast
// objects an array of objects
var castRay = function(ray,objects){
var i,minDist;
minDist = ray.len; // set the min dist to the rays length
i = objects.length; // number of objects to check
while(i > 0){
i -= 1;
minDist = Math.min(objects[i].rayDist(ray), minDist);
}
ray.len = minDist;
}
//========================================================================
// Draws all objects
// objects an array of objects
var drawObjects = function(objects){
var i = objects.length; // number of objects to check
while(i > 0){
objects[--i].draw(COLOUR, LINE_WIDTH);
}
}
//========================================================================
// called on start and resize
// creats a new scene each time
// fits the canvas to the avalible realestate
function reMakeAll(){
w = canvas.width = window.innerWidth;
h = canvas.height = window.innerHeight;
ctx = canvas.getContext("2d");
screenDiagonal = Math.hypot(window.innerWidth,window.innerHeight);
if(ray === undefined){
ray = createRay(0,0,0,screenDiagonal);
}
objects.length = 0;
var i = OBJ_COUNT;
while( i > 0 ){
var objectRandom = Math.floor(rand(0, 4));
if(objectRandom === 1){
objects.push(createWall(rand(0, w), rand(0, h), rand(screenDiagonal * 0.1, screenDiagonal * 0.2), rand(0, Math.PI * 2)));
}else if(objectRandom === 2){
objects.push(createPolygon(rand(0, w), rand(0, h)));
}else if(objectRandom === 3){
objects.push(createSquare(rand(0, w), rand(0, h), rand(screenDiagonal * 0.02, screenDiagonal * 0.05), rand(screenDiagonal * 0.02, screenDiagonal * 0.05)));
}else{
objects.push(createCircle(rand(0, w), rand(0, h), rand(screenDiagonal * 0.02, screenDiagonal * 0.05)));
}
i -= 1;
}
}
//========================================================================
function mouseMoveEvent(event){
mouse.x = event.clientX;
mouse.y = event.clientY;
}
//========================================================================
// updates all that is needed when needed
function updateAll(time){
var i;
ctx.clearRect(0,0,w,h);
ray.x = mouse.x;
ray.y = mouse.y;
drawObjects(objects);
i = 0;
while(i < NUMBER_RAYS){
ray.setDir(i * RAY_DIR_SPACING + time * RAY_ROTATE_SPEED);
ray.len = screenDiagonal;
castRay(ray,objects);
ray.draw(RAY_COLOUR, RAY_LINE_WIDTH);
i ++;
}
requestAnimationFrame(updateAll);
}
// add listeners
window.addEventListener("resize",reMakeAll);
canvas.addEventListener("mousemove",mouseMoveEvent);
// set it all up
reMakeAll();
// start the ball rolling
requestAnimationFrame(updateAll);

Rotating Images & Pixel Collision Detection

I've got this game in this plunker.
When the swords are not rotating, it all works fine (you can check by uncommenting lines 221 and commenting out 222-223). When they are rotating like in the plunker above, the collision doesn't work well.
I guess that's because the "getImageData" remembers the old images, but I gather it's an expensive thing to recalculate over and over again.
Is there a better way to rotate my images and make this work? Or do I have to recalculate their pixel map?
Code of the culprit:
for (var i = 0; i < monsters.length; i++) {
var monster = monsters[i];
if (monster.ready) {
if (imageCompletelyOutsideCanvas(monster, monster.monsterImage)) {
monster.remove = true;
}
//else {
//ctx.drawImage(monster.monsterImage, monster.x, monster.y);
drawRotatedImage(monster.monsterImage, monster.x, monster.y, monster);
monster.rotateCounter += 0.05;
//}
}
}

Geometric solution
To do this via a quicker geometry solution.
The simplest solution is a line segment with circle intersection algorithm.
Line segment.
A line has a start and end described in a variety of ways. In this case we will use the start and end coordinates.
var line = {
x1 : ?,
y1 : ?,
x2 : ?,
y2 : ?,
}
Circle
The circle is described by its location and radius
var circle = {
x : ?,
y : ?,
r : ?,
}
Circle line segment Intersect
The following describes how I test for the circle line segment collision. I don't know if there is a better way (most likely there is) but this has served me well and is reliable with the caveat that line segments must have length and circles must have area. If you can not guarantee this then you must add checks in the code to ensure you don't get divide by zeros.
Thus to test if a line intercepts the circle we first find out how far the closest point on the line (Note a line is infinite in size while a line segment has a length, start and end)
// a quick convertion of vars to make it easier to read.
var x1 = line.x1;
var y1 = line.y1;
var x2 = line.x2;
var y2 = line.y2;
var cx = circle.x;
var cy = circle.y;
var r = circle.r;
The result of the test, will be true if there is a collision.
var result; // the result of the test
Convert the line to a vector.
var vx = x2 - x1; // convert line to vector
var vy = y2 - y1;
var d2 = (vx * vx + vy * vy); // get the length squared
Get the unit distance from the circle of the near point on the line. The unit distance is a number from 0, to 1 (inclusive) and represents the distance along the vector of a point. if the value is less than 0 then the point is before the vector, if greater then 1 the point is past the end.
I know this by memory and forget the concept. Its the dot product of the line vector and the vector from the start of the line segment to the circle center divided by the line vectors length squared.
// dot product of two vectors is v1.x * v2.x + v1.y * v2.y over v1 length squared
u = ((cx - x1) * vx + (cy - y1) * vy) / d2;
Now use the unit position to get the actual coordinate of the point on the line closest to the circle by adding to the line segment start position the line vector times the unit distance.
// get the closest point
var xx = x1 + vx * u;
var yy = y1 + vy * u;
Now we have a point on the line, we calculate the distance from the circle using pythagoras square root of the sum of the two sides squared.
// get the distance from the circle center
var d = Math.hypot(xx - cx, yy - cy);
Now if the line (not line segment) intersects the circle the distance will be equal or less than the circle radius. Otherwise the is no intercept.
if(d > r){ //is the distance greater than the radius
result = false; // no intercept
} else { // else we need some more calculations
To determine if the line segment has intercepted the circle we need to find the two points on the circle's circumference that the line has crossed. We have the radius and the distance the circle is from the line. As the distance from the line is always at right angles we have a right triangle with the hypot being the radius and one side being the distance found.
Work out the missing length of the triangle. UPDATE see improved version of the code from here at bottom of answer under "update" it uses unit lengths rather than normalise the line vector.
// ld for line distance is the square root of the hyp subtract side squared
var ld = Math.sqrt(r * r - d * d);
Now add that distance to the point we found on the line xx, yy to do that normalise the line vector (makes the line vector one unit long) by dividing the line vector by its length, and then to multiply it by the distance found above
var len = Math.sqrt(d2); // get the line vector length
var nx = (vx / len) * ld;
var ny = (vy / len) * ld;
Some people may see that I could have used the Unit length and skipped a few calculations. Yes but I can be bothered rewriting the demo so will leave it as is
Now to get the to intercept points by adding and subtracting the new vector to the point on the line that is closest to the circle
ix1 = xx + nx; // the point furthest alone the line
iy1 = xx + ny;
ix2 = xx - nx; // the point in the other direction
iy2 = xx - ny;
Now that we have these two points we can work out if they are in the line segment but calculating the unit distance they are on the original line vector, using the dot product divide the squared distance.
var u1 = ((ix1 - x1) * vx + (iy1 - y1) * vy) / d2;
var u2 = ((ix2 - x1) * vx + (iy1 - y1) * vy) / d2;
Now some simple tests to see if the unit postion of these points are on the line segment
if(u1 < 0){ // is the forward intercept befor the line segment start
result = false; // no intercept
}else
if(u2 > 1){ // is the rear intercept after the line end
result = false; // no intercept
} else {
// though the line segment may not have intercepted the circle
// circumference if we have got to here it must meet the conditions
// of touching some part of the circle.
result = true;
}
}
Demo
As always here is a demo showing the logic in action. The circle is centered on the mouse. There are a few test lines that will go red if the circle touches them. It will also show the point where the circle circumference does cross the line. The point will be red if in the line segment or green if outside. These points can be use to add effects or what not
I am lazy today so this is straight from my library. Note I will post the improved math when I get a chance.
Update
I have improved the algorithm by using unit length to calculate the circle circumference intersects, eliminating a lot of code. I have added it to the demo as well.
From the Point where the distance from the line is less than the circle radius
// get the unit distance to the intercepts
var ld = Math.sqrt(r * r - d * d) / Math.sqrt(d2);
// get that points unit distance along the line
var u1 = u + ld;
var u2 = u - ld;
if(u1 < 0){ // is the forward intercept befor the line
result = false; // no intercept
}else
if(u2 > 1){ // is the backward intercept past the end of the line
result = false; // no intercept
}else{
result = true;
}
}
var demo = function(){
// the function described in the answer with extra stuff for the demo
// at the bottom you will find the function being used to test circle intercepts.
/** GeomDependancies.js begin **/
// for speeding up calculations.
// usage may vary from descriptions. See function for any special usage notes
var data = {
x:0, // coordinate
y:0,
x1:0, // 2nd coordinate if needed
y1:0,
u:0, // unit length
i:0, // index
d:0, // distance
d2:0, // distance squared
l:0, // length
nx:0, // normal vector
ny:0,
result:false, // boolean result
}
// make sure hypot is suported
if(typeof Math.hypot !== "function"){
Math.hypot = function(x, y){ return Math.sqrt(x * x + y * y);};
}
/** GeomDependancies.js end **/
/** LineSegCircleIntercept.js begin **/
// use data properties
// result // intercept bool for intercept
// x, y // forward intercept point on line **
// x1, y1 // backward intercept point on line
// u // unit distance of intercept mid point
// d2 // line seg length squared
// d // distance of closest point on line from circle
// i // bit 0 on for forward intercept on segment
// // bit 1 on for backward intercept
// ** x = null id intercept points dont exist
var lineSegCircleIntercept = function(ret, x1, y1, x2, y2, cx, cy, r){
var vx, vy, u, u1, u2, d, ld, len, xx, yy;
vx = x2 - x1; // convert line to vector
vy = y2 - y1;
ret.d2 = (vx * vx + vy * vy);
// get the unit distance of the near point on the line
ret.u = u = ((cx - x1) * vx + (cy - y1) * vy) / ret.d2;
xx = x1 + vx * u; // get the closest point
yy = y1 + vy * u;
// get the distance from the circle center
ret.d = d = Math.hypot(xx - cx, yy - cy);
if(d <= r){ // line is inside circle
// get the distance to the two intercept points
ld = Math.sqrt(r * r - d * d) / Math.sqrt(ret.d2);
// get that points unit distance along the line
u1 = u + ld;
if(u1 < 0){ // is the forward intercept befor the line
ret.result = false; // no intercept
return ret;
}
u2 = u - ld;
if(u2 > 1){ // is the backward intercept past the end of the line
ret.result = false; // no intercept
return ret;
}
ret.i = 0;
if(u1 <= 1){
ret.i += 1;
// get the forward point line intercepts the circle
ret.x = x1 + vx * u1;
ret.y = y1 + vy * u1;
}else{
ret.x = x2;
ret.y = y2;
}
if(u2 >= 0){
ret.x1 = x1 + vx * u2;
ret.y1 = y1 + vy * u2;
ret.i += 2;
}else{
ret.x1 = x1;
ret.y1 = y1;
}
// tough the points of intercept may not be on the line seg
// the closest point to the must be on the line segment
ret.result = true;
return ret;
}
ret.x = null; // flag that no intercept found at all;
ret.result = false; // no intercept
return ret;
}
/** LineSegCircleIntercept.js end **/
// mouse and canvas functions for this demo.
/** fullScreenCanvas.js begin **/
var canvas = (function(){
var canvas = document.getElementById("canv");
if(canvas !== null){
document.body.removeChild(canvas);
}
// creates a blank image with 2d context
canvas = document.createElement("canvas");
canvas.id = "canv";
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
canvas.style.position = "absolute";
canvas.style.top = "0px";
canvas.style.left = "0px";
canvas.style.zIndex = 1000;
canvas.ctx = canvas.getContext("2d");
document.body.appendChild(canvas);
return canvas;
})();
var ctx = canvas.ctx;
/** fullScreenCanvas.js end **/
/** MouseFull.js begin **/
var canvasMouseCallBack = undefined; // if needed
var mouse = (function(){
var mouse = {
x : 0, y : 0, w : 0, alt : false, shift : false, ctrl : false,
interfaceId : 0, buttonLastRaw : 0, buttonRaw : 0,
over : false, // mouse is over the element
bm : [1, 2, 4, 6, 5, 3], // masks for setting and clearing button raw bits;
getInterfaceId : function () { return this.interfaceId++; }, // For UI functions
startMouse:undefined,
};
function mouseMove(e) {
var t = e.type, m = mouse;
m.x = e.offsetX; m.y = e.offsetY;
if (m.x === undefined) { m.x = e.clientX; m.y = e.clientY; }
m.alt = e.altKey;m.shift = e.shiftKey;m.ctrl = e.ctrlKey;
if (t === "mousedown") { m.buttonRaw |= m.bm[e.which-1];
} else if (t === "mouseup") { m.buttonRaw &= m.bm[e.which + 2];
} else if (t === "mouseout") { m.buttonRaw = 0; m.over = false;
} else if (t === "mouseover") { m.over = true;
} else if (t === "mousewheel") { m.w = e.wheelDelta;
} else if (t === "DOMMouseScroll") { m.w = -e.detail;}
if (canvasMouseCallBack) { canvasMouseCallBack(m.x, m.y); }
e.preventDefault();
}
function startMouse(element){
if(element === undefined){
element = document;
}
"mousemove,mousedown,mouseup,mouseout,mouseover,mousewheel,DOMMouseScroll".split(",").forEach(
function(n){element.addEventListener(n, mouseMove);});
element.addEventListener("contextmenu", function (e) {e.preventDefault();}, false);
}
mouse.mouseStart = startMouse;
return mouse;
})();
if(typeof canvas === "undefined"){
mouse.mouseStart(canvas);
}else{
mouse.mouseStart();
}
/** MouseFull.js end **/
// helper function
function drawCircle(ctx,x,y,r,col,col1,lWidth){
if(col1){
ctx.lineWidth = lWidth;
ctx.strokeStyle = col1;
}
if(col){
ctx.fillStyle = col;
}
ctx.beginPath();
ctx.arc( x, y, r, 0, Math.PI*2);
if(col){
ctx.fill();
}
if(col1){
ctx.stroke();
}
}
// helper function
function drawLine(ctx,x1,y1,x2,y2,col,lWidth){
ctx.lineWidth = lWidth;
ctx.strokeStyle = col;
ctx.beginPath();
ctx.moveTo(x1,y1);
ctx.lineTo(x2,y2);
ctx.stroke();
}
var h = canvas.height;
var w = canvas.width;
var unit = Math.ceil(Math.sqrt(Math.hypot(w, h)) / 32);
const U80 = unit * 80;
const U60 = unit * 60;
const U40 = unit * 40;
const U10 = unit * 10;
var lines = [
{x1 : U80, y1 : U80, x2 : w /2, y2 : h - U80},
{x1 : w - U80, y1 : U80, x2 : w /2, y2 : h - U80},
{x1 : w / 2 - U10, y1 : h / 2 - U40, x2 : w /2, y2 : h/2 + U10 * 2},
{x1 : w / 2 + U10, y1 : h / 2 - U40, x2 : w /2, y2 : h/2 + U10 * 2},
];
function update(){
var i, l;
ctx.clearRect(0, 0, w, h);
drawCircle(ctx, mouse.x, mouse.y, U60, undefined, "black", unit * 3);
drawCircle(ctx, mouse.x, mouse.y, U60, undefined, "yellow", unit * 2);
for(i = 0; i < lines.length; i ++){
l = lines[i]
drawLine(ctx, l.x1, l.y1, l.x2, l.y2, "black" , unit * 3)
drawLine(ctx, l.x1, l.y1, l.x2, l.y2, "yellow" , unit * 2)
// test the lineSegment circle
data = lineSegCircleIntercept(data, l.x1, l.y1, l.x2, l.y2, mouse.x, mouse.y, U60);
// if there is a result display the result
if(data.result){
drawLine(ctx, l.x1, l.y1, l.x2, l.y2, "red" , unit * 2)
if((data.i & 1) === 1){
drawCircle(ctx, data.x, data.y, unit * 4, "white", "red", unit );
}else{
drawCircle(ctx, data.x, data.y, unit * 2, "white", "green", unit );
}
if((data.i & 2) === 2){
drawCircle(ctx, data.x1, data.y1, unit * 4, "white", "red", unit );
}else{
drawCircle(ctx, data.x1, data.y1, unit * 2, "white", "green", unit );
}
}
}
requestAnimationFrame(update);
}
update();
}
// resize if needed by just starting again
window.addEventListener("resize",demo);
// start the demo
demo();

... and here's how to find the sword blade lines when the sword is moved & rotated
Start by finding the vertices of the original sword blade and saving them in an array.
var pts=[{x:28,y:42},{x:69,y:3},{x:83,y:1},{x:83,y:19},{x:42,y:57}];
When the sword rotates, each blade vertex point will rotate around the rotation point. In your case the rotation point is the center of the image.
Gray rect is the rectangular border of the image
Blue dot is one sword vertex (at the tip of the blade)
Green dot is at the center of the image (== the rotation point)
Green line is the distance from center-image to vertex
Blue circle is the path the blade tip will follow as it rotates 360 degrees
The green line will change its angle depending on the image's rotation.
You can calculate the position of the blade tip at any angle of rotation like this:
// [cx,cy] = the image centerpoint (== the rotation point)
// [vx,vy] = the coordinate position of the blade tip
// Calculate the distance and the angle between the 2 points
var dx=vx-cx;
var dy=vy-cy;
var distance=Math.sqrt(dx*dx+dy*dy);
var originalAngle=Math.atan2(dy,dx);
// rotationAngle = the angle the image has been rotated expressed in radians
var rotatedX = cx + distance * Math.cos(originalAngle + rotationAngle);
var rotatedY = cy + distance * Math.sin(originalAngle + rotationAngle);
Here's example code and a Demo that tracks blade vertices while being moved and rotated:
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var cw=canvas.width;
var ch=canvas.height;
function reOffset(){
var BB=canvas.getBoundingClientRect();
offsetX=BB.left;
offsetY=BB.top;
}
var offsetX,offsetY;
reOffset();
window.onscroll=function(e){ reOffset(); }
window.onresize=function(e){ reOffset(); }
var isDown=false;
var startX,startY;
var sword={
img:null,
rx:0,
ry:0,
angle:0,
pts:[{x:28,y:42},{x:69,y:3},{x:83,y:1},{x:83,y:19},{x:42,y:57}],
// precalculated properties -- for efficiency
radii:[],
angles:[],
halfWidth:0,
halfHeight:0,
//
initImg:function(img){
var PI2=Math.PI*2;
this.img=img;
this.halfWidth=img.width/2;
this.halfHeight=img.height/2;
for(var i=0;i<this.pts.length;i++){
var dx=this.halfWidth-this.pts[i].x;
var dy=this.halfHeight-this.pts[i].y;
this.radii[i]=Math.sqrt(dx*dx+dy*dy);
this.angles[i]=((Math.atan2(dy,dx)+PI2)%PI2)-Math.PI;
}
},
// draw sword with translation & rotation
draw:function(){
var img=this.img;
var rx=this.rx;
var ry=this.ry;
var angle=this.angle;
ctx.translate(rx,ry);
ctx.rotate(angle);
ctx.drawImage(img,-this.halfWidth,-this.halfHeight);
ctx.rotate(-angle);
ctx.translate(-rx,-ry);
},
// recalc this.pts after translation & rotation
calcTrxPts:function(){
var trxPts=[];
for(var i=0;i<this.pts.length;i++){
var r=this.radii[i];
var ptangle=this.angles[i]+this.angle;
trxPts[i]={
x:this.rx+r*Math.cos(ptangle),
y:this.ry+r*Math.sin(ptangle)
};
}
return(trxPts);
},
}
// load image & initialize sword object & draw scene
var img=new Image();
img.onload=function(){
// set initial sword properties
sword.initImg(img);
sword.rx=150;
sword.ry=75;
sword.angle=0; //(Math.PI/8);
// draw scene
drawAll();
// listen for mouse events
$("#canvas").mousedown(function(e){handleMouseDown(e);});
$("#canvas").mousemove(function(e){handleMouseMove(e);});
$("#canvas").mouseup(function(e){handleMouseUpOut(e);});
$("#canvas").mouseout(function(e){handleMouseUpOut(e);});
// listen for mousewheel events
$("#canvas").on('DOMMouseScroll mousewheel',function(e){
e.preventDefault();
e.stopPropagation();
var e=e || window.event; // old IE support
sign=((e.originalEvent.wheelDelta||e.originalEvent.detail*-1)>0)?1:-1;
sword.angle+=Math.PI/45*sign;
drawAll();
});
}
img.src = "data:image/png;base64,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";
/////////////////////
// helper functions
/////////////////////
function drawAll(){
ctx.clearRect(0,0,cw,ch);
sword.draw();
drawHitArea();
}
function drawHitArea(){
// lines
var trxPts=sword.calcTrxPts();
ctx.beginPath();
ctx.moveTo(trxPts[0].x,trxPts[0].y);
for(var i=1;i<trxPts.length;i++){
ctx.lineTo(trxPts[i].x,trxPts[i].y);
}
ctx.closePath();
ctx.strokeStyle='red';
ctx.stroke();
// dots
for(var i=0;i<trxPts.length;i++){
ctx.beginPath();
ctx.arc(trxPts[i].x,trxPts[i].y,3,0,Math.PI*2);
ctx.closePath();
ctx.fillStyle='blue';
ctx.fill();
}
}
function getClosestPointOnLineSegment(line,x,y) {
//
lerp=function(a,b,x){ return(a+x*(b-a)); };
var dx=line.x1-line.x0;
var dy=line.y1-line.y0;
var t=((x-line.x0)*dx+(y-line.y0)*dy)/(dx*dx+dy*dy);
var lineX=lerp(line.x0, line.x1, t);
var lineY=lerp(line.y0, line.y1, t);
return({x:lineX,y:lineY,isOnSegment:(t>=0 && t<=1)});
};
function handleMouseDown(e){
// tell the browser we're handling this event
e.preventDefault();
e.stopPropagation();
startX=parseInt(e.clientX-offsetX);
startY=parseInt(e.clientY-offsetY);
// Put your mousedown stuff here
isDown=true;
}
function handleMouseUpOut(e){
// tell the browser we're handling this event
e.preventDefault();
e.stopPropagation();
// clear the isDragging flag
isDown=false;
}
function handleMouseMove(e){
if(!isDown){return;}
// tell the browser we're handling this event
e.preventDefault();
e.stopPropagation();
// calc distance moved since last drag
mouseX=parseInt(e.clientX-offsetX);
mouseY=parseInt(e.clientY-offsetY);
var dx=mouseX-startX;
var dy=mouseY-startY;
startX=mouseX;
startY=mouseY;
// drag the sword to new position
sword.rx+=dx;
sword.ry+=dy;
drawAll();
}
body{ background-color: ivory; }
#canvas{border:1px solid red; }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<h6>Drag sword and<br>Rotate sword using mousewheel inside canvas<br>Red "collision" lines follow swords translation & rotation.</h6>
<h5></h5>
<canvas id="canvas" width=300 height=300></canvas>