Make it easy to write a custom renderer

[emersion]

The only way to create a custom renderer right now is to fork render/gles. But IMHO there's an opportunity to share code in a better way between the GLES2 renderer, maybe a future GLES3 renderer and compositor's custom renderers.

• Share code in wlr_egl
• Untie wlr_gles2_renderer and wlr_gles2_texture
• Make wlr_gles2_texture re-usable in external renderers
• Make wlr_gles2_renderer re-usable in external renderers

Share code in wlr_egl

Some EGL code is in the renderer. We can share more by moving some functions (those which create EGLSurfaces for instance) into wlr_egl.

Make wlr_texture a reusable type

Right now wlr_texture is tied to the wlr_renderer. But it would be possible to untie it from the renderer, making it reusable in another renderer. For a custom GLES2 renderer (e.g. a 3D one) this would be helpful.

Export wlr_gles2_* functions

This will allow custom renderers to choose what to re-use, and to build a wlr_gles2_renderer wrapper.

[emersion]

This proposal is outdated, closing.