Also use BufferData(NULL) to get fresh storage and avoid synchronous
operation where we would have to flush and wait for the fence after each
draw because of the map.
This will chew through a whole load of buffer space on small draws, so
it isn't a proper solution. Need to support a no-fence or append mapping
mode to do this right, or use user buffers.
This controls whether the window origin is considered to be the lower-left
or upper-left corner.
This effects computation of gl_FragCoord and the application of polygon stipple.
We were doing this for the sake of softpipe and the tgsi intergrepter since
we always need the fragment position and W-coordinate information in order
to compute fragment interpolants.
But that's not appropriate for hardware drivers.
The tgsi interpreter now get x,y,w information from a separate tgsi_exec_vector
variable setup by softpipe.
The new pipe_shader_state->input_map[] defines how vert shader outputs map
to frag shader inputs. It may go away though, since one can also examine
the semantic label on frag shader input[0] to figure things out.
The tgsi linear/perspective attribute code now uses these values rather than
input[0]. Need to update SSE path to take quad x,y as function params.
Then, we can remove additional code.
This should be moved into a gallium util lib (location tbd) so it can also
be used by the state tracker.
Then, remove the pipe->get/put_tile_rgba() functions.
st_create_framebuffer() now takes pipe_formats for the color, depth, stencil
buffers.
This avoids a round-about chain of calls to pipe->is_format_supported() for
window renderbuffers (their format never changes).
Renderbuffer format selection code in st_format.c is simpler now too.
