a067e7a16b
The current framebuffer is now internally separated so that there can be a different draw and read buffer. This is required to use the GL_EXT_framebuffer_blit extension. The current draw and read buffers are stored as a pair in a single stack so that pushing the draw and read buffer is done simultaneously with the new _cogl_push_framebuffers internal function. Calling cogl_pop_framebuffer will restore both the draw and read buffer to the previous state. The public cogl_push_framebuffer function is layered on top of the new function so that it just pushes the same buffer for both drawing and reading. When flushing the framebuffer state, the cogl_framebuffer_flush_state function now tackes a pointer to both the draw and the read buffer. Anywhere that was just flushing the state for the current framebuffer with _cogl_get_framebuffer now needs to call both _cogl_get_draw_buffer and _cogl_get_read_buffer.