In gl-renderer.c:gl_renderer_attach_shm: glBindTexture(GL_TEXTURE_2D, gs->textures[0]); glTexImage2D(GL_TEXTURE_2D, 0, GL_BGRA_EXT, gs->pitch, buffer->height, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, NULL); i.e. texture with GL_BGRA internal format is created for surface. Later in gl-renderer.c:gl_renderer_flush_damage: switch (wl_shm_buffer_get_format(buffer->shm_buffer)) { ... case WL_SHM_FORMAT_RGB565: format = GL_RGB; pixel_type = GL_UNSIGNED_SHORT_5_6_5; break; ... } glTexSubImage2D(GL_TEXTURE_2D, 0, r.x1, r.y1, r.x2 - r.x1, r.y2 - r.y1, format, pixel_type, data); i.e. glTexSubImage2D is called with format = GL_RGB and type = GL_UNSIGNED_SHORT_5_6_5, while texture's internal format is GL_BGRA. Such combination is incorrect and it works only because of OpenGL driver implementor's good will
Thanks for the bug report. I've posted a patch to the mailing list which could fix this: http://lists.freedesktop.org/archives/wayland-devel/2014-April/014066.html
Committed on master: commit 39a443ff9b42ac3a2f7ec3f58230051f2031af24 Author: Neil Roberts <neil@linux.intel.com> Date: Fri Apr 4 16:24:54 2014 +0100 Always use glTexImage2D instead of glTexSubImage2D for first upload Previously when uploading SHM data we would initialise the texture with glTexImage2D and NULL data when the buffer is attached. Then if the GL_EXT_unpack_subimage extension is available we would always use glTexSubImage2D to upload the data. The problem with that is that the first glTexImage2D was always setting the internal format to GL_BGRA_EXT and then if a 16-bit texture is used we would later call glTexSubImage2D with a data format of GL_RGBA. Under GLES2 the internal format must always match the data format so this is technically invalid. This patch makes it so that it always calls glTexImage2D when flushing the damage for the first time. That way it will use the right internal format and we don't need to call glTexImage2D with NULL data. https://bugs.freedesktop.org/show_bug.cgi?id=75251
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