Hi Kristian, I'm working on Raspberry Pi, where the VideoCore can deal directly with a large number of pixel formats. However, wl_shm only exposes ARGB and XRGB 32-bit per pixel formats, which on such tiny devices are very wasteful.
Would it be acceptable to add more formats to the wl_shm formats enum? I have happily forgot all the previous discussions about the topic, and a quick search into the mailing list archives didn't turn up much. We are especially interested in 16-bit per pixel formats to save memory and bandwidth, and if I am reading the GLESv2 specification right, RGB565, RGBA4444 and RGBA5551 should be directly supported, so at least those could be uploaded into textures without manual conversion. Of course, the new rpi-renderer I am working on does not use GL for compositing anymore, but it should be able to use those formats directly, too. I have also another proposition: an extension to let wl_shm support custom pixel formats outside of the core protocol listed formats. It would have a new global interface, which when bound, would advertise additional pixel formats as a (string, uint) tuple, where the string describes the pixel format, and the uint is the corresponding format name to pass into wl_shm_pool.create_buffer as the format argument. wl_shm would not advertise these format names itself. We would need to define a WL_SHM_FORMAT_CUSTOM_BASE to reserve some name space for the custom formats. Or something along those lines. Of course, this is just working around the pixel format enum wl_shm has anyway, so if you would be willing to take more exotic pixel formats into the wl_shm format enum, this extension would not be needed. Does any of this sound acceptable for upstream Wayland, or do you think we'd better just write a new wl_buffer factory with everything we need? Btw. Google found this: http://people.freedesktop.org/~krh/fourcc.patch Why was that or similar never used? :-) Thanks, pq _______________________________________________ wayland-devel mailing list wayland-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/wayland-devel
