svga: do not emulate wide points in GS when doing transform feedback

Emulating wide points in geometry shader when doing transform feedback
is problematic. This patch disables the emulation.

Tested with piglit test ext_transform_feedback-points.
Also tested with MTT glretrace, mesa demos pointblast and spriteblast.

Reviewed-by: Brian Paul <brianp@vmware.com>

diff --git a/src/gallium/drivers/svga/svga_state_tgsi_transform.c b/src/gallium/drivers/svga/svga_state_tgsi_transform.c
index 9e643ff49a751a9804722586406b97ca986970da..b567aab6bc810bafed7628dcf5684e4248951931 100644 (file)
--- a/src/gallium/drivers/svga/svga_state_tgsi_transform.c
+++ b/src/gallium/drivers/svga/svga_state_tgsi_transform.c
@@ -249,9 +249,11 @@ update_tgsi_transform(struct svga_context *svga, unsigned dirty)
    if (svga->curr.reduced_prim == PIPE_PRIM_POINTS) {
       /* If the current prim type is POINTS and the current geometry shader
        * emits wide points, transform the shader to emulate wide points using
-       * quads.
+       * quads. NOTE: we don't do emulation of wide points in GS when
+       * transform feedback is enabled.
        */
-      if (gs != NULL && (gs->base.info.writes_psize || gs->wide_point)) {
+      if (gs != NULL && !gs->base.stream_output &&
+          (gs->base.info.writes_psize || gs->wide_point)) {
          orig_gs = gs->base.parent ? gs->base.parent : &gs->base;
          new_gs = emulate_point_sprite(svga, orig_gs, orig_gs->tokens);
       }
@@ -260,7 +262,7 @@ update_tgsi_transform(struct svga_context *svga, unsigned dirty)
        * shader emits wide point then create a new geometry shader to emulate
        * wide point.
        */
-      else if (gs == NULL &&
+      else if (gs == NULL && !vs->base.stream_output &&
                (svga->curr.rast->pointsize > 1.0 ||
                 vs->base.info.writes_psize)) {
          new_gs = add_point_sprite_shader(svga);