* is set then calls _mesa_update_state() to update gl_frame_buffer::_Xmin,
* etc. If the rasterization mode is set to GL_RENDER then requests the driver
* to clear the buffers, via the dd_function_table::Clear callback.
* is set then calls _mesa_update_state() to update gl_frame_buffer::_Xmin,
* etc. If the rasterization mode is set to GL_RENDER then requests the driver
* to clear the buffers, via the dd_function_table::Clear callback.