This commit implements WebGL's:
* cullFace
* frontFace
* enable
* disable
* depthMask
* colorMask
* clearDepth
* clearStencil
* depthFunc
* depthRange
* hint
* lineWidth
* pixelStorei
* polygonOffset
* texParameteri
* texParameterf
* texImage2D (partially)
It inlines a lot of OpenGL calls to keep the file
`components/canvas/webgl_paint_task.rs` as small as possible while
keeping readability.
It also improves error detection on previous calls, and sets node damage
on the canvas in the drawing calls.
It adds a `TexImage2D` reftest, even though it's not enabled because:
* WebGL paints the image when it loads (asynchronously), so the reftest doesn't wait for it and it finishes early
* If we change the source for the base64 src of the image it works as expected in non-headless mode, but the test harness locks
This improves the encapsulation and consistency in our WebGL
implementation.
Also allows to implement new methods such as `getShaderSource()`.
It will also allow us to use `delete()` in the destructors of them (note
that we will want to keep track of them from the context).
This commit implements:
* WebGLFramebuffer
* WebGLRenderbuffer
* WebGLTexture
And adds the following methods to `WebGLRenderingContext`:
* create{Texture,Framebuffer,Renderbuffer}
* bind{Texture,Framebuffer,Renderbuffer}
* destroy{Buffer,Texture,Framebuffer,Renderbuffer}
Fixes:
* WebGLUniform location shouldn't inherit from WebGLObject.
Known Issues:
* WebGL objects have to be destroyed on drop, we may want to keep a reference to the context, or maybe a clone of the renderer to achieve this
Also refactors a huge part of the current implementation, to allow
failing on creation of different WebGL objects.
Blocked on https://github.com/servo/gleam/pull/22
A reftest for most of the added functionality is not doable right now,
we need a few more functions in order to upload a texture, for example.
This implements the `canvas`, `drawingBufferHeight` and
`drawingBufferWidth` getters to `WebGLRenderingContext`, and an initial
version of `getParameter`.
