my link: http://dl.dropbox.com/u/7727742/playlistsite6/index5.html
I have a 3d cube using a variation of zachstronaut's demo
(link: http://www.zachstronaut.com/lab/galaxy-box/ ). It uses javascript, translate3d, scale3d, etc...
I've tried assigning different z-index values in the css file, but with no luck. I can access the objects outside the cube(you can see this with the hover effect), but not the objects inside the cube. I have a hunch it is because it's not doing a z-sort type of function like pre3d.js. I was wondering if anyone could offer some insight into where I should look for a solution.
Object coordinates are generated randomly, so you may have to refresh once or twice to get some objects that are inside the cube.
Thanks!
EDIT:
Only tested in safari and chrome dev
Webkit ignores z-indexes on anything that has translate3d defined, as it logically should. z-index is meant for a 2D world, it's like taking a bunch of paper and saying "this one is on top" -- you still have a flat surface. Unfortunately, if you want to be able to select one of the "stars" inside of your box, you're all but out of luck since you're using HTML nodes.
The normal way of doing this is using a click-map -- basically every object gets rendered twice. Once normally and once in a single color with no shading, etc. The 2nd rendering is never shown and is simply used to tell what the user clicked on. You get the color where they clicked and that color maps to a specific object. If you were using canvas, you would do it that way and just change the rendering order on the 2nd render.
Since you're using HTML nodes, you can't do that. You have a couple of options:
You can calculate which star is under the mouse on mouse-move based on viewport rotation and x/y/z position of the star
you can attempt the above method by overlaying an identical rendering without the cube and where the stars have a 0% opacity. Each star in your new rendering would map to a star in your existing one, and you'd have easy mouse-over detection.
Post the results! :)
First of all, I'm glad you found my demo interesting!
You're not going to have much luck trying to do a hover or capture a click event on objects inside of a 3D CSS3 cube for the exact same reason you wouldn't have much luck capturing a hover or click events on a div underneath another div... in HTML all the DOM events go to the top most DOM node. If one div overlaps another div, you can't click the one that is underneath. Everything inside the 3D cube is "underneath" another DOM node.
Things are further complicated because you're taking objects in 3D space and asking a user to interact with them on a 2D plane (the browser window) using a 2D input device (the mouse).
You could hide the faces of the cube so that they wouldn't block the user's clicks. You could do something like cwolves suggested.
Sorry I couldn't be more help... HTML kind of fails us a bit here. Welcome to the bleeding edge!
Related
I am building a web based chess game in Javascript. I'm using the HTML5 canvas to display the board by drawing rectangles.
I am trying to implement the move logic. So when a chess piece is clicked, and then they click on an empty block, I want to move it. However, it is quite tedious using the canvas. I need to do the following:
Update my 2D grid of objects to reflect the change, I set the current
square to undefined and set the new square to the object being moved
clearRect(..) which I still haven't got to work
Redraw the image at the new position
Is there a better way?
Also, how do I deal with the 'double click'. I currently using a boolean that holds if the piece was pressed, and if it was and they click on an empty square I call the move function. Are there any other ways of doing this? Additionally, are there any tools for making it seem like the chess piece is being dragged?
I appreciate any help. Thanks guys.
Over the years I've written a lot of chessboards for HTML. In the end the simplest approach I think is:
Keep an array (either 1d or 2d, both have pros and cons) with just piece names (e.g. "wp"=white pawn, "bn"=black night, "--" empty). Nothing to be gained with an OO-approach or even a generic piece object.
Use one single canvas for the board, drawing the pieces on them with drawImage.
Write a function that just draws everything and call it when needed (don't bother erasing/drawing single pieces).
For piece dragging empty the square and create a separate dragged div containing just the dragged piece (redrawing the full board during drag can be slow for low-end mobile devices).
For dragging attach move and up handlers to the document and not to the canvas, so that you won't miss up events when the mouse is outside of the browser window.
Start dragging on mousedown and attach events for mousemove and mouseup. This will work both on computers and on mobile phones without having to handle specific cases. Always call preventDefault and stopPropagation.
Make full-page view with no overflow and handle resize yourself (you'll need to add some mobile-specific metas to stop phones messing up with the page).
HTML can really do impressive things with just 2d canvas, as an example see this 2d/3d chessboard. One single file less than 300k (200k zipped).
Easiest you say?
Using chessboard.js has to be the easiest way and it is 2D.
HTML
<div id="board1" style="width: 400px"></div>
JavaScript
var board1 = ChessBoard('board1', 'start');
It has very good documentation and tons of different examples (customization) and can be downloaded here.
Learning by coding -- Good for you!
Here are a few tips to get you started:
A reusable structure for your game:
Create a JS object for each of your chess pieces and save those piece-objects in an array.
// an example piece object
var blackKing={
player:'black',
pieceType:'king',
image:blackKingImageObject,
currentSquare:['E','1'],
isCaptured: false,
// etc...
}
// a pieces-array
var pieces=[];
pieces.push(blackKing);
Create a function that does all of these things:
clearRect the entire canvas,
redraw the chess board,
use the piece-array to redraw all the pieces onto the chessboard.
About click vs double-click vs dragging:
Yes, that's troublesome and requires special handling.
Many coders handle it this way:
Listen for mousedown and save that timestamp and initial mouse position.
If a mouseup plus another mousedown occurs quickly it's a double-click.
If a mousemove of more than a few pixels occurs then it's the start of a drag.
Otherwise, it's a single-click.
I'm pretty new to event-handling inside svgs and there is a little weirdness happening here. I'm doing an infovis where I build an interface and want to display different column-graphs.
That's rather easy and working pretty nicely.
But I'm using hover-events to show the actual numbers when hovering a rect. it works with the one chart I'm generating first. But even though that chart is hidden (I tried both: visibility: hidden and display: none properties) the one that's drawn first still gets the event.
Do I need to remove that one completely in order to generate a new one? So should I better work with separate SVGs and have an external interface, hiding the different svgs?
Any advice/best-practice would be welcome!
Thanks already!
Suse
The other way of hiding things is to push them off the screen, as with hidden iframes. Just give them a negative x/y position. That should take care of mouse-over issues.
If I have a canvas with a circle that changes color upon clicking on it, I can use a click event on the canvas element and handle the math for that (distance formula calculation <= radius). But what if I have two circles that overlap (like a van diagram), and I click in the middle of the two circles assuming that only the top circle should change color? If the math of the first circle is applied in this case, both circles would change color.
How would I deal with events in the canvas in terms of overlapping objects like the example above? With hopefully a fast/efficient algorithm?
You might want a framework like EaselJS that has a better api for what you're trying to do. Barebones canvas 2d-context doesn't provide much in terms of display-object / sprite behavior.
Responses above also mention some sort of list to represent layers. I don't think the implementation would be very difficult, just another condition to check for along with the radius.
Canvas isn't really like Flash or like a DOM tree whereby things have sort orders or z-indexes. Its a bit more like a flat rastered image and you have to rely upon other logic in your javascript to remember the sequence & stacking order of things you have drawn.
If you need this kind of interactivity I've always found it best to use a 3rd party library (unless it really is just a case of one or two circles which dont do much).
For interactive 'shape' based javascript graphics I would sugest Raphael.js or D3 which are actually more of SVG tools than a canvas one so maybe it's not for you but they are simple and cross-browser.
There's also processing.js (js port of Processing the Java lib) which feels a bit like flash and again can track all of the levels and objects. Theres a tonne of others but thats another topic.
If it's super simple the options might be:
Hold the co-ordinates of all shapes/elements composited on the canvas inside an object or array which also tracks their z-index/sort sequence, thereby letting you know whats on top.
Using the imagedata at the mouse coordinate of the click to establish what has been clicked
using multiple canvases composited on each other and letting the DOM do the work for the click events
I've been working on building a tile-based display grid for canvas. This is what I have so far: http://jsfiddle.net/dDmTf/7/
Some problems I'm having, and can't quite grasp are:
The initial load time is ridiculous... I don't understand what I'm doing wrong - fixed, found out I was rendering ^32 more than I was supposed to
The hover effect, which "should" just highlight the border of the tile, erases it, and I have no way of recovering the previous tile without re-rendering the entire canvas.
How do I use tilesheets, providing me a single image instead of a bunch of small ones
Resizing the window (which resizes the canvas) also erases the canvas. Do I need to re-render? Or can I maintain state of various things when width/height is changed - added an onresize callback, which re-renders the map. Might not be the best way though?
Multiple layers? How would I go about allowing transparency .png files overlaying each-other
Those are the main problems I'm stuck on right now, and any guidance would be majorly appreciated.
Also, if you have any pointers for my javascript, feel free! I'm learning it more as I go, and I'm sure I'm doing a lot of things wrong.
Edit
As an FYI, I just copy-pasted the sprite map currently being shown on the jsfiddle. It's not the one I'm planning to use, but it was easier than uploading one. I plan to maintain a 32x32 grid instead of (what appears to be) a 16x16 grid from that tilesheet
Edit
I've got the a 32x32 tilesheet displaying on there now, but the hover effect is still breaking it, and I'm not sure how to "know" what the old value was.
The problem is that you are not redrawing your tiles after 'mouseout'.
You either need to redraw the single tile after you move out of it, but this can get tricky as things get more complicated or better yet on mouse move do the following.
Clear the canvas
draw the grid
draw your tiles
then do the highlighting/clearing that cell.
If you end up having any sort of animation this is the process that will be used anyhow otherwise as something moves from one tile to another it will leave ghost images behind.
How would I create a DIV containing an IMG where the DIV cuts the image into a triangle, thereby displaying only part of the image though a triangle.
so..
<div>
<img src='some_image' />
</div>
Where the image is a square, but the DIV containing the image is a triangle.
http://www.script-tutorials.com/creating-kaleidoscope-using-jquery-and-css/ solves this very well except this solution is not x-browser friendly (non-ie).
http://css3pie.com/ looks interesting, however this relies on PHP.
You can't create a non-rectangular DOM element.
There are a few ways to hack it.
Firstly, there is a method of using CSS borders with varying widths on each side of the element to make it look triangular. It will still be a rectangle, but it will look like a triangle.
There's a tutorial on this here: http://www.russellheimlich.com/blog/pure-css-shapes-triangles-delicious-logo-and-hearts/
The down-side of this approach is that it is limited to creating right-angled triangles. You can join several of them together to get around this, but then you don't have a single container for your image.
An alternative hacky way of doing it would be to place rotated elements on top of the main element so that they cover the appropriate parts of the image and make it look triangular. This works in all browsers, although IE does have some very nasty syntax to do rotation, and it's quite heavy on the browser, considering that you'd only be using it to make shapes.
Another option might be to use CSS transforms. However this is only supported by a minority of up-to-date browsers, so it won't work for most users.
A better approach might be to use a proper graphics library for this, rather than trying to shoe-horn it into a <div> element.
I'd recommend using Raphael. It's a Javascript library which can draw directly into the browser using SVG (or VML for IE). It's trivial to create triangles using it and to fill them with a graphic. See the examples on the Raphael home page to get you started.
Depending on what you want the outcome to be, as far as i'm aware you cant make a triangle DIV without Transform:; However one solution would be having a div positioned inside the div in question with a PNG cutting of half the image showing only the transparent part through. Not sure if this is a viable option for you though.