gallium: new draw stage for polygon stipple.

For hardware without native polygon stipple.  Create a 32x32 alpha texture
that encodes the stipple pattern.  Modify the user's fragment program to
sample the texture (with gl_FragCoord) and kill the fragment according to
the texel value.
Temporarily enabled in softpipe driver, replacing the sp_quad_stipple.c step.

3 files changed, 14 insertions, 0 deletions

diff --git a/src/gallium/drivers/softpipe/sp_context.c b/src/gallium/drivers/softpipe/sp_context.c
index de4c6c18e7..2cdf3c75bf 100644
--- a/src/gallium/drivers/softpipe/sp_context.c
+++ b/src/gallium/drivers/softpipe/sp_context.c
@@ -332,6 +332,11 @@ struct pipe_context *softpipe_create( struct pipe_winsys *pipe_winsys,
    draw_install_aaline_stage(softpipe->draw, &softpipe->pipe);
    draw_install_aapoint_stage(softpipe->draw, &softpipe->pipe);
 
+#if USE_DRAW_STAGE_PSTIPPLE
+   /* Do polygon stipple w/ texture map + frag prog? */
+   draw_install_pstipple_stage(softpipe->draw, &softpipe->pipe);
+#endif
+
    /* sp_prim_setup can do wide points (don't convert to quads) */
    draw_convert_wide_points(softpipe->draw, FALSE);
 
diff --git a/src/gallium/drivers/softpipe/sp_context.h b/src/gallium/drivers/softpipe/sp_context.h
index a50cee7648..feeafc7084 100644
--- a/src/gallium/drivers/softpipe/sp_context.h
+++ b/src/gallium/drivers/softpipe/sp_context.h
@@ -39,6 +39,13 @@
 #include "sp_quad.h"
 
 
+/**
+ * This is a temporary variable for testing draw-stage polygon stipple.
+ * If zero, do stipple in sp_quad_stipple.c
+ */
+#define USE_DRAW_STAGE_PSTIPPLE 1
+
+
 struct softpipe_winsys;
 struct softpipe_vbuf_render;
 struct draw_context;
diff --git a/src/gallium/drivers/softpipe/sp_quad.c b/src/gallium/drivers/softpipe/sp_quad.c
index 6bd468a51c..15b5594547 100644
--- a/src/gallium/drivers/softpipe/sp_quad.c
+++ b/src/gallium/drivers/softpipe/sp_quad.c
@@ -112,7 +112,9 @@ sp_build_quad_pipeline(struct softpipe_context *sp)
       sp_push_quad_first( sp, sp->quad.earlyz );
    }
 
+#if !USE_DRAW_STAGE_PSTIPPLE
    if (sp->rasterizer->poly_stipple_enable) {
       sp_push_quad_first( sp, sp->quad.polygon_stipple );
    }
+#endif
 }