On Fri, 2019-04-26 at 23:31 -0400, Marek Olšák wrote: I don't claim to know what this series is trying to fix, but:
> + * 2) Pbuffers are back buffers from the application point of view, > + * but they are front buffers from the Mesa point of view, > + * because they are always single buffered. > + */ The EGL spec (back to 1.0!) says: "The resulting pbuffer will contain color buffers and ancillary buffers as specified by config." This appears to be copied from GLX, which has something more elaborate: "The resulting pbuffer will contain color buffers and ancillary buffers as specified by config. It is possible to create a pbuffer with back buffers and to swap the front and back buffers by calling glXSwapBuffers. Note that pbuffers use framebuffer resources so applications should consider deallocating them when they are not in use." So I'm not convinced that pbuffers are "always single-buffered". The back buffer is definitely a color buffer, and at least under GLX it seems like it should be possible to draw red to back, swap, draw blue to back, glReadBuffer(GL_FRONT), and expect glReadPixels to return red. - ajax _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
