1 files changed, 77 insertions, 0 deletions
diff --git a/src/gallium/drivers/softpipe/sp_quad_stipple.c b/src/gallium/drivers/softpipe/sp_quad_stipple.c
new file mode 100644
index 0000000000..07162db7b6
--- /dev/null
+++ b/src/gallium/drivers/softpipe/sp_quad_stipple.c
@@ -0,0 +1,77 @@
+
+/**
+ * quad polygon stipple stage
+ */
+
+#include "sp_context.h"
+#include "sp_quad.h"
+#include "sp_quad_pipe.h"
+#include "pipe/p_defines.h"
+#include "util/u_memory.h"
+
+
+/**
+ * Apply polygon stipple to quads produced by triangle rasterization
+ */
+static void
+stipple_quad(struct quad_stage *qs, struct quad_header *quad)
+{
+   static const uint bit31 = 1 << 31;
+   static const uint bit30 = 1 << 30;
+
+   if (quad->input.prim == QUAD_PRIM_TRI) {
+      struct softpipe_context *softpipe = qs->softpipe;
+      /* need to invert Y to index into OpenGL's stipple pattern */
+      const int col0 = quad->input.x0 % 32;
+      const int y0 = quad->input.y0;
+      const int y1 = y0 + 1;
+      const uint stipple0 = softpipe->poly_stipple.stipple[y0 % 32];
+      const uint stipple1 = softpipe->poly_stipple.stipple[y1 % 32];
+
+      /* turn off quad mask bits that fail the stipple test */
+      if ((stipple0 & (bit31 >> col0)) == 0)
+         quad->inout.mask &= ~MASK_TOP_LEFT;
+
+      if ((stipple0 & (bit30 >> col0)) == 0)
+         quad->inout.mask &= ~MASK_TOP_RIGHT;
+
+      if ((stipple1 & (bit31 >> col0)) == 0)
+         quad->inout.mask &= ~MASK_BOTTOM_LEFT;
+
+      if ((stipple1 & (bit30 >> col0)) == 0)
+         quad->inout.mask &= ~MASK_BOTTOM_RIGHT;
+
+      if (!quad->inout.mask) {
+         /* all fragments failed stipple test, end of quad pipeline */
+         return;
+      }
+   }
+
+   qs->next->run(qs->next, quad);
+}
+
+
+static void stipple_begin(struct quad_stage *qs)
+{
+   qs->next->begin(qs->next);
+}
+
+
+static void stipple_destroy(struct quad_stage *qs)
+{
+   FREE( qs );
+}
+
+
+struct quad_stage *
+sp_quad_polygon_stipple_stage( struct softpipe_context *softpipe )
+{
+   struct quad_stage *stage = CALLOC_STRUCT(quad_stage);
+
+   stage->softpipe = softpipe;
+   stage->begin = stipple_begin;
+   stage->run = stipple_quad;
+   stage->destroy = stipple_destroy;
+
+   return stage;
+}