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I don't want to spoil their great "innovation patent" but Three.js has implemented this years ago (http://threejs.org/docs/#Reference/Renderers/CanvasRenderer).

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Does that reconstruct quads as the Zynga post described? From the source code, it seems to just draw the triangles individually:

https://github.com/mrdoob/three.js/blob/1769fbfc6c994b51a54c...

I also don't see any heuristic processing of shaders as described for ZyGL.

three.js removed support for quads to reduce renderer complexity.

https://github.com/mrdoob/three.js/blob/master/src/core/Face...

https://github.com/mrdoob/three.js/blob/88092284cbe07723fe2b...

And the relevant issue: https://github.com/mrdoob/three.js/issues/3663

Even before that change, I don't see any code that automatically reconstructs construct quads from pairs of triangles. But maybe I'm missing something?

No, you're right, there's no quad reconstruction. I imagine you could have just used quads in both the WebGL and Canvas renderers to achieve a similar effect.

(I've been working on OpenGL platform translation for years)

Reconstructing quads from pairs of triangles is just about doable in a one-liner. The harder part in my opinion is applying texture mapping to the resulting triangle, but it's not unreasonably difficult.

    // this depends on your winding
    triangles = [1, 2, 4, 2, 3, 4]
    quads = []
    for i in xrange(len(triangles), 6):
        t = triangles[i:i+6]
        quads += [t[0], t[1], t[4], t[2]]

The only things I think are interesting here are their heuristics on shaders to apply color maps, and the fact they shipped a game with it.

I don't know what exactly is being patented. As I read it, the novel part is this:

So, what about that arbitrary shader code? In practice, the shaders used in 2D games tend to be fairly simple. ZyGL applies a series of heuristics to the shader code to try to infer its intent. It then uses these heuristics to map the draw calls through to some approximations of common shader code that we wrote in JavaScript.

I'm not aware of any prior art that is (a) a polyfill for WebGL using canvas that also (b) reconstructs triangle strips into canvas quads and (c) attempts to mimic shader effects by scanning the shader code for common techniques.

This is the first time someone's announced a patent for a space I'm in. I have no idea what implications this has for me, but I may have some prior art on "software rasterization of OpenGL code that only uses it for 2D", including quad recovery.

Pixi.js ( http://www.pixijs.com ) supports WebGL with an automatic canvas fallback as well (and is also used as the renderer by Javascript game frameworks like Phaser.io and Panda.js).

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