1 files changed, 94 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 00000000000..ccf37f6be59
--- /dev/null
+++ b/src/gallium/drivers/softpipe/sp_quad_stipple.c
@@ -0,0 +1,94 @@
+
+/**
+ * quad polygon stipple stage
+ */
+
+#include "sp_context.h"
+#include "sp_headers.h"
+#include "sp_quad.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 == PRIM_TRI) {
+      struct softpipe_context *softpipe = qs->softpipe;
+      /* need to invert Y to index into OpenGL's stipple pattern */
+      int y0, y1;
+      uint stipple0, stipple1;
+      if (softpipe->rasterizer->origin_lower_left) {
+         y0 = softpipe->framebuffer.height - 1 - quad->input.y0;
+         y1 = y0 - 1;
+      }
+      else {
+         y0 = quad->input.y0;
+         y1 = y0 + 1;
+      }
+      stipple0 = softpipe->poly_stipple.stipple[y0 % 32];
+      stipple1 = softpipe->poly_stipple.stipple[y1 % 32];
+
+#if 1
+      {
+      const int col0 = quad->input.x0 % 32;
+      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;
+      }
+#else
+      /* We'd like to use this code, but we'd need to redefine
+       * MASK_TOP_LEFT to be (1 << 1) and MASK_TOP_RIGHT to be (1 << 0),
+       * and similarly for the BOTTOM bits.  But that may have undesirable
+       * side effects elsewhere.
+       */
+      const int col0 = 30 - (quad->input.x0 % 32);
+      quad->inout.mask &= (((stipple0 >> col0) & 0x3) | 
+                     (((stipple1 >> col0) & 0x3) << 2));
+#endif
+      if (!quad->inout.mask)
+         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;
+}