I have a canvas for the game world and a canvas for the display screen. I also have a polygon with nodes V(x,y) to serve as a viewport that follows the player and his rotation. I would like to know how to clip from the game world along the polygon, rotate and draw to the smaller canvas.`
//main looping function
var requestAnimFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback){
window.setTimeout(callback, 1000 / 60);
};
})();
//joystick setup
var leftManager = null;
var rightManager = null;
//precalculated math
var twoPi = Math.PI*2;
var halfPi = Math.PI/2;
var thirdOfCircleInRadians = twoPi/3;
//game canvas setup
var gameCvs = document.getElementById('gameCanvas');
gameCvs.width = 480;
gameCvs.height = 320;
//gameCvs.width - 960;
//gameCvs.height = 640;
var gameCtx = gameCvs.getContext("2d");
//game loop
var lastTime = 0;
function main() {
var now = Date.now();
var dt = lastTime==0? 0.016 : (now - lastTime) / 1000.0;
update(dt);
render(dt);
lastTime = now;
requestAnimFrame(main);
}
//collision class shorthand
var V = SAT.Vector;
var C = SAT.Circle;
var P = SAT.Polygon;
var R = new SAT.Response();
P.prototype.draw = function (ctx,type) {
ctx.save();
switch(type){
case 'van': ctx.fillStyle = "rgba(66, 66, 66, 0.5)"; break;
case 'col': ctx.fillStyle = "rgba(0, 0, 0, 1.0)"; break;
default: ctx.fillStyle = "rgba(0, 0, 0, 1.0)"; break;
}
ctx.translate(this.pos.x, this.pos.y);
ctx.beginPath();
var points = this.calcPoints;
ctx.moveTo(points[0].x, points[0].y);
var i = points.length;
while (i--) ctx.lineTo(points[i].x, points[i].y);
ctx.closePath();
//stroke to see through camera, when camera is not drawn use fill
ctx.stroke();
//ctx.fill();
ctx.restore();
};
//first for collisions, second for vanity. first is black, second is grey
var O = function(colPolygon,vanPolygon){
this.colPolygon = colPolygon;
this.vanPolygon = vanPolygon;
this.visible = false;
};
var objectVendor = function(type,position){
switch(type){
case 'tree':
return new O(new P(position,[
new V(10.5,19.5),
new V(20.5,9.5),
new V(23,-4),
new V(15,-16.5),
new V(-4,-19.5),
new V(-18,-14.5),
new V(-23,-0.5),
new V(-18.5,14.5),
new V(-8,20)
]),new P(position,[
new V(21,39),
new V(41,19),
new V(46,-8),
new V(30,-33),
new V(-8,-39),
new V(-36,-29),
new V(-46,-1),
new V(-37,29),
new V(-16,40)]));
break;
default: return false; break;
}
return false;
}
//Camera and Player Polygons
var cameraPoly = new P(new V(0,0),[
new V(-240,-160),
new V(240,-160),
new V(240,160),
new V(-240,160)
]);
var player = new P(new V(0,0),[
new V(5,2.5),
new V(7.5,2),
new V(7.5,-2),
new V(5,-2.5),
new V(-5,-2.5),
new V(-7.5,-2),
new V(-7.5,2),
new V(-5,2.5)
]);
//players start position on the screen, and starting angle, init velocity
player.pos = new V(240,160);
player.setAngle(1);
//players velocity for movement
player.vel = new V(0,0);
var world = {
objects: [],
visibleObjects: [],
worldCvs: null,
worldCtx: null,
init: function(){
//set up world canvas
this.worldCvs = document.createElement('canvas');
this.worldCvs.width = 480;
this.worldCvs.height = 480;
this.worldCtx = this.worldCvs.getContext("2d");
//populate world with stuff
this.objects.push(objectVendor('tree',new V(100,100)));
this.objects.push(objectVendor('tree',new V(150,200)));
this.objects.push(objectVendor('tree',new V(75,300)));
},
update: function(dt){
this.visibleObjects = [];
cameraPoly.setAngle(player.angle);
//cameraPoly.pos = player.pos;
cameraPoly.pos = new V(player.pos.x+(110*Math.cos(player.angle+halfPi)),player.pos.y+(110*Math.sin(player.angle+halfPi)));
//update objects to mark if they are in view
var i = this.objects.length;
while(i--){
if(SAT.testPolygonPolygon(this.objects[i].vanPolygon, cameraPoly, R)){
this.visibleObjects.push(this.objects[i]);
}
}
//}
},
draw: function(dt){
this.worldCtx.setTransform(1,0,0,1,0,0);
this.worldCtx.clearRect(0,0,this.worldCvs.width,this.worldCvs.height);
player.draw(this.worldCtx);
var i = this.visibleObjects.length;
while(i--){
this.visibleObjects[i].colPolygon.draw(this.worldCtx,'col');
this.visibleObjects[i].vanPolygon.draw(this.worldCtx,'van');
}
//for testing
cameraPoly.draw(this.worldCtx);
/*
this.worldCtx.save();
this.worldCtx.beginPath();
var i = cameraPoly.calcPoints.length;
this.worldCtx.moveTo(cameraPoly.calcPoints[0].x,cameraPoly.calcPoints[0].y);
while(i--){
this.worldCtx.lineTo(cameraPoly.calcPoints[i].x,cameraPoly.calcPoints[i].y);
}
this.worldCtx.clip();
this.worldCtx.restore();
*/
}
}
function render(dt){
gameCtx.setTransform(1,0,0,1,0,0);
gameCtx.clearRect(0,0,gameCvs.width,gameCvs.height);
world.draw();
//gameCtx.save();
//gameCtx.translate(cameraPoly.pos.x,cameraPoly.pos.y);
//gameCtx.translate(gameCtx.width/2,gameCtx.height/2);
//gameCtx.rotate(-player.angle+halfPi);
//gameCtx.translate(-world.worldCvs.width/2,-world.worldCvs.height/2);
gameCtx.drawImage(world.worldCvs,0,0);
//gameCtx.restore();
}
function update(dt){
world.update();
}
function init(){
//joystick setup
leftManager = nipplejs.create({
zone:document.getElementById("leftJoystick"),
color:"black",
size:75,
threshold:1.0,
position:{
top:"50%",
left:"50%"
},
mode:"static",
restOpacity:0.75,
});
rightManager = nipplejs.create({
zone:document.getElementById("rightJoystick"),
color:"black",
size:75,
threshold:1.0,
position:{
top:"50%",
right:"50%"
},
mode:"static",
restOpacity:0.75,
});
//joystick event setup
leftManager.get().on('move end', function(evt,data){
//console.log(evt);
//console.log(data);
});
rightManager.get().on('move end', function(evt,data){
//console.log(evt);
//console.log(data);
});
world.init();
main();
}
init();
`
I'm using libraries SAT.js and nipplejs.js currently.
Typically this is done in a little different of a way than you seem to be thinking of it. Instead of thinking about the viewport existing somewhere in the world, you should think about the viewport being fixed and the world being transformed behind it; you don't copy part of the world to the viewport, you draw the world offset and rotated by a certain amount, and only draw the parts that are inside the viewport. Matrices are an easy and common way to represent this transformation. You may want to read more about them here.
In practice, this would just amount to changing your existing call to worldCtx.setTransform() at the beginning of each draw frame. That link has information about how to calculate a good transform matrix, and you can find similar resources all over the place since it's pretty standard math.
In particular, you'll want to multiply a rotation and a translation matrix. Translation matrices are only possible if you use a matrix with higher-order than your coordinate space; for 2D, a 3x3 matrix, and for 3D, a 4x4 matrix. You could instead choose to just add some offset to your coordinates as you draw them, but worldCtx.setTransform already takes a matrix with a 3rd column for putting flat offsets into.
Changing the render function to the following will solve the problem, just rushing myself and didn't think things through very well.
`
function render(dt){
gameCtx.setTransform(1,0,0,1,0,0);
gameCtx.clearRect(0,0,gameCvs.width,gameCvs.height);
world.draw();
gameCtx.translate(gameCvs.width/2,gameCvs.height/2);
gameCtx.rotate(-player.angle+Math.PI);
gameCtx.translate(-cameraPoly.pos.x,-cameraPoly.pos.y);
gameCtx.drawImage(world.worldCvs,0,0);
}`
What this is doing is resetting any transformations on the context, clearing it for a new redrawing, creating the world canvas, translating to display center, rotating by the proper amount for reference point, translating to reference center point on negative axis to move game canvas proper amount so that drawing at 0,0 is in the correct location. Thank you for the reference material!
I have a drawing canvas using EaselJS, the problem is that when I am drawing lines is working properly only the first one. Since second line is getting with some corners not with curved line as the first line, and it looks more like a polygon than a curved line. What is the best way to fix this?
I think here should to be something to correct
//containers
this.backgroundContainer = new createjs.Container();
this.stage.addChild(this.backgroundContainer);
var ss = new createjs.Shape();
ss.graphics.beginFill("#000000").drawRect(0, 0, 960, window.innerHeight);
this.stageArea = new createjs.Container();
this.stageArea.snapToPixel = true;
this.stageArea.hitArea = ss;
this.backgroundContainer.addChild(this.stageArea);
this.container = new createjs.Container();
this.stage.addChild(this.container);
this.stageArea.addEventListener("mousedown", this.handleMouseDown);
this.stage.addEventListener("stagemousemove" , this.handleMouseMove);
tick:function(){
if(app.mouseDOWN){
app.midPt = new createjs.Point(app.oldPt.x + app.stage.mouseX - app.stage.canvas.width/2>>1, app.oldPt.y+app.stage.mouseY - app.stage.canvas.height/2>>1);
app.lineArray[app.NUM_LINES].graphics
.beginStroke('#ffffff')
.moveTo(app.midPt.x, app.midPt.y)
.curveTo(app.oldPt.x, app.oldPt.y, app.oldMidPt.x, app.oldMidPt.y);
app.lineArray2[app.NUM_LINES].graphics
.beginStroke('#ffffff')
.moveTo(app.midPt.x, app.midPt.y)
.curveTo(app.oldPt.x, app.oldPt.y, app.oldMidPt.x, app.oldMidPt.y);
app.lineArray3[app.NUM_LINES].graphics
.beginStroke('#ffffff')
.moveTo(app.midPt.x, app.midPt.y)
.curveTo(app.oldPt.x, app.oldPt.y, app.oldMidPt.x, app.oldMidPt.y);
app.oldPt.x = app.stage.mouseX;
app.oldPt.y = app.stage.mouseY;
app.oldMidPt.x = app.midPt.x;
app.oldMidPt.y = app.midPt.y;
app.stage.update();
}
}
I want to create a Pine using 2 meshes, 1 for the trunk and another one for the bush, this what I've done:
var pine_geometry = new THREE.Geometry();
var pine_texture_1 = THREE.ImageUtils.loadTexture('./res/textures/4.jpg');
var pine_geometry_1 = new THREE.CylinderGeometry(25, 25, 50, 6);
var pine_material_1 = new THREE.MeshBasicMaterial({
map : pine_texture_1
});
var pine_1 = new THREE.Mesh(pine_geometry_1);
pine_1.position.x = x;
pine_1.position.y = y + 25;
pine_1.position.z = z;
pine_1.updateMatrix();
pine_geometry.merge(pine_1.geometry, pine_1.matrix);
var pine_texture_2 = THREE.ImageUtils.loadTexture('./res/textures/5.jpg');
var pine_geometry_2 = new THREE.CylinderGeometry(0, 70, 250, 8);
var pine_material_2 = new THREE.MeshBasicMaterial({
map : pine_texture_2
});
var pine_2 = new THREE.Mesh(pine_geometry_2);
pine_2.position.x = x;
pine_2.position.y = y + 175;
pine_2.position.z = z;
pine_2.updateMatrix();
pine_geometry.merge(pine_2.geometry, pine_2.matrix);
var pine = new THREE.Mesh(pine_geometry, new THREE.MeshFaceMaterial([pine_material_1, pine_material_2]));
pine.geometry.computeFaceNormals();
pine.geometry.computeVertexNormals();
Game.scene.add(pine);
The Pine is correctly positioned as I want, however, the whole merged shape only uses 1 material instead of the 2 (the whole shape is covered by the 1st) and I want that each mesh has it's respective material when mergin both.
What I'm doing wrong? any idea?
After a long research I discovered that I was missing an extra parameter for the method 'merge' from the Geometry object, the last parameter is the index of the material that the mesh must have from the materials array, ex: 0 -> first material in 'materials' array... and so on.
So, my final piece of code looks like:
pine_geometry.merge(pine_1.geometry, pine_1.matrix, 0);
var pine_texture_2 = THREE.ImageUtils.loadTexture('./res/textures/5.jpg');
var pine_geometry_2 = new THREE.CylinderGeometry(0, 70, 250, 8);
var pine_material_2 = new THREE.MeshBasicMaterial({
map : pine_texture_2
});
var pine_2 = new THREE.Mesh(pine_geometry_2);
pine_2.position.x = x;
pine_2.position.y = y + 175;
pine_2.position.z = z;
pine_2.updateMatrix();
pine_geometry.merge(pine_2.geometry, pine_2.matrix, 1);
(Note the last numbers I add to each merge).
However, I want to clarify that this practice only works when we are dealing with various geometries that are from the same type, in this case, we're merging two CylinderGeometry, but if we wanted to merge for example a Cylinder with a Box AND add the MeshFaceMaterial, it wouldn't be recognized properly and the console will throw us 'Cannot read property map/attributes from undefined', nevertheless we can still merge both geometries but not providing multiple materials (that's a terrible mistake I made).
Hope this helps to anyone.
Here's a general function to merge meshes with materials, You can also specify if you want it to return it as a buffer geometry.
function _mergeMeshes(meshes, toBufferGeometry) {
var finalGeometry,
materials = [],
mergedGeometry = new THREE.Geometry(),
mergeMaterial,
mergedMesh;
meshes.forEach(function(mesh, index) {
mesh.updateMatrix();
mesh.geometry.faces.forEach(function(face) {face.materialIndex = 0;});
mergedGeometry.merge(mesh.geometry, mesh.matrix, index);
materials.push(mesh.material);
});
mergedGeometry.groupsNeedUpdate = true;
mergeMaterial = new THREE.MeshFaceMaterial(materials);
if (toBufferGeometry) {
finalGeometry = new THREE.BufferGeometry().fromGeometry(mergedGeometry);
} else {
finalGeometry = mergedGeometry;
}
mergedMesh = new THREE.Mesh(finalGeometry, mergeMaterial);
mergedMesh.geometry.computeFaceNormals();
mergedMesh.geometry.computeVertexNormals();
return mergedMesh;
}
var mergedMesh = _mergeMeshes([trunkMesh, treeTopMesh], true);
How to draw circular segment using paper.js
I want to draw the circular segments as shown in the image. Each segment is independent and will later be used for interactive purposes.
I tried something like
//Temporary background circle
var keys = new Path.Circle(view.center, 130);
keys.fillColor = '#F1F1F1';
var home = new Path.Circle(view.center, 50);
home.fillColor = '#ee2a33';
var start = new Point(view.center.x, view.center.y-130);
var through = new Point(view.center.x-125, view.center.y-40);
var to = new Point(view.center.x-130, view.center.y);
var path = new Path.Arc(start, through, to);
path.strokeColor = 'black';
path.fillColor = 'green';
And it renders something like below
After several attempts, I came up with this. If anyone needs the same thing for whatever reason, maybe this will help.
//Creating keys
var arcOne = createSegment('#f1f1f1');
var arcTwo = createSegment('#666666');
var arcThree = createSegment('#333333');
var arcFour = createSegment('#666666');
var arcFive = createSegment('#999999');
var arcSix = createSegment('#000000');
arcTwo.rotate(-60, view.center);
arcThree.rotate(-120, view.center);
arcFour.rotate(60, view.center);
arcFive.rotate(120, view.center);
arcSix.rotate(180, view.center);
//center white
var center = new Path.Circle(view.center, 50);
center.fillColor = '#F1F1F1';
//Create Each segment
function createSegment(fillcolor){
//Segment One
var start = new Point(view.center.x, view.center.y-130);
var through = new Point(view.center.x-90, view.center.y-94);
var to = new Point(view.center.x-113, view.center.y-64);
var name = Path.Arc(start, through, to);
name.add(new Point(view.center.x, view.center.y));
name.add(new Point(view.center.x, view.center.y-130));
name.fillColor = fillcolor;
return name;
}