Compositing Mode in Weston

Weston supports mixed mode compositing using dma-buf. Weston collects all the overlay planes and assigns one to the GFX as the primary plane. Others are available as overlay planes. Weston evaluates all surfaces and views on every frame, and chooses one of these strategies to composite them:

• DRM_OUTPUT_PROPOSE_STATE_MIXED (Overlay + GL)
• DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY (GL)
• DRM_OUTPUT_PROPOSE_STATE_PLANES_ONLY (Overlay only)

The weston-simple-dmabuf-egldevice demo application demonstrates mixed-mode compositing path in weston, where some surfaces are assigned overlay planes and others are composited with GL.