Work in progress.

As with static objects, faster with OpenGL (34 -> 38 fps) and slower with ANGLE (30 -> 27 fps).

Also fixed subtle bug in `materials_gl` example: face.material => face.materials (since renaming this example was just silently broken)

Also fixed quads vertex color bug in WebGLRenderer and did small optimization of face state handling.

On my notebook WebGLRenderer now 35% faster than WebGLRenderer2 (in OpenGL, in ANGLE it's still 15% slower, go figure).

Small optimizations: skipped flattening in 3x3 matrix inversion and uploading camera position uniform only for materials where it's used.

This should affect only use cases with lots of animated objects (unlike current performance tests where object matrices are not updated).

As for particles, performance should be the same just using less memory.

Refactored WebGLRenderer to be able to handle MeshShaderMaterial also for Lines and ParticleSystems.

It is now object type that determines which type of primitives is going to be used (triangles / lines / line strips / points).

That was painful; hopefully since now it should be easier to have it in every WebGL example.

It's enough to add one line (ideally as the first thing that gets executed):

    if ( ! THREE.Supports.webgl ) THREE.Supports.addGetWebGLMessage();

This will add message box with default styling centered near top of the window. Optional parameters "parent" and "id" can be specified for further customization and integration with the document, also message DOM element is returned for easier access.

    var messageElement = THREE.Supports.addGetWebGLMessage( { parent: container, id: "my_message" } );

By default, message is added to document.body and has id "oldie" (can be styled with CSS).

Created "THREE.Supports" object, which should centralize this stuff. So far it detects <canvas>, WebGL and WebWorkers; later it could detect for example GPU capabilities.

Not sure about name or location, but it's pretty tiring go through all examples when something changes, so it should be somewhere in the library.

Code duplication is bad: even html snippets with error message should be centralized somewhere, so that when new browsers arrive we wouldn't have to keep changing them in many places.

There shouldn't be performance difference, just less memory used (indices were not used anyways).

WebGLRenderer now as fast as WebGLRenderer2.

Many balls demos now noticeably faster ;)

Also doing less matrix multiplications (though this just seems to have shifted bottleneck elsewhere).

This is to be able to control depth buffer writing / testing on per geometry chunk level (before it was possible just to hack it on per scene level via exposed GL context).

Disabling depth test is useful for example for additively blended particles, handling of transparency or for having background textured quad.

Another option would be to have it on per object level, but then this could prevent different handling of objects with both transparent and opaque parts.

Also in this commit:

- more progress towards mesh vertex colors
- less matrix multiplications in render call
- fixed ugly bug in doubleSided / flipSided handling
- cleanup of materials
    - added a lot of missing stuff in debug strings and parameters handlers
    - normal and depth materials now have opacity parameter
    - wrote comments for non-obvious things

Vertex colors for meshes in progress ...

Renamed: setClearColor( hex, opacity ) => setClearColorHex( hex, opacity )

New: setClearColor( color, opacity )

In this way it's a bit cheaper to animate clear color.

Hope I didn't break examples - I searched for "setClearColor" and changed it in one place where it was used.

Very much work-in-progress. Expect things to change.

Also changed film shader to have optional grayscale (controlled via uniform).

Work in progress, caveats:

- sort happens just inside one ParticleSystems, so everything gets messed up when more ParticleSystems are in the same screen space
- not yet solved proper order of operations, if you change object transform, you need to update ParticleSystem object matrix manually before rendering (so that sort works, otherwise it will use transform from previous frame)

Also fixed transparency in fog and did small optimizations in WebGLRenderer.