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This PR provides the base for implementing WebGL extensions. It comes with the following ones already implemented and passing all related WebGL conformance tests:
- OES_texture_float
- OES_texture_float_linear
- OES_texture_half_float
- OES_texture_half_float_linear
- OES_vertex_array_object
I'll submit other extensions like compressed textures in a separate PR to ease the review process. I included the 5 extensions in this PR because it's easier to show/review how the WebGL extension base works.
To pass all OES_texture_float_xxx tests I had to add some missing format conversions in WebGLRenderingContext.rs
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Source-Repo: https://github.com/servo/servo
Source-Revision: b0976566fb9c79f7dc67b2ac808eb50ef4ad653f