1 files changed, 152 insertions, 0 deletions
diff --git a/src/mesa/pipe/draw/draw_twoside.c b/src/mesa/pipe/draw/draw_twoside.c
new file mode 100644
index 00000000000..5e9f218d1e9
--- /dev/null
+++ b/src/mesa/pipe/draw/draw_twoside.c
@@ -0,0 +1,152 @@
+/**************************************************************************
+ * 
+ * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+/* Authors:  Keith Whitwell <[email protected]>
+ */
+#include "imports.h"
+#include "vf/vf.h"
+
+#include "pipe/p_defines.h"
+#include "sp_context.h"
+#include "sp_prim.h"
+
+
+struct twoside_stage {
+   struct prim_stage stage;
+   
+   GLfloat facing;
+   const GLuint *lookup;
+};
+
+
+static INLINE struct twoside_stage *twoside_stage( struct prim_stage *stage )
+{
+   return (struct twoside_stage *)stage;
+}
+
+
+static void twoside_begin( struct prim_stage *stage )
+{
+   struct twoside_stage *twoside = twoside_stage(stage);
+
+   twoside->facing = (stage->softpipe->setup.front_winding == PIPE_WINDING_CW) ? -1 : 1;
+
+   stage->next->begin( stage->next );
+}
+
+
+static INLINE void copy_color( GLuint attr_dst,
+			       GLuint attr_src,
+			       struct vertex_header *v )
+{
+   if (attr_dst && attr_src) {
+      memcpy( v->data[attr_dst],
+	      v->data[attr_src],
+	      sizeof(v->data[0]) );
+   }
+}
+
+
+static struct vertex_header *copy_bfc( struct twoside_stage *twoside, 
+				       const struct vertex_header *v,
+				       GLuint idx )
+{   
+   struct vertex_header *tmp = dup_vert( &twoside->stage, v, idx );
+   
+   copy_color( twoside->lookup[VF_ATTRIB_COLOR0], 
+	       twoside->lookup[VF_ATTRIB_BFC0],
+	       tmp );
+
+   copy_color( twoside->lookup[VF_ATTRIB_COLOR1], 
+	       twoside->lookup[VF_ATTRIB_BFC1],
+	       tmp );
+
+   return tmp;
+}
+
+
+/* Twoside tri:
+ */
+static void twoside_tri( struct prim_stage *stage,
+			 struct prim_header *header )
+{
+   struct twoside_stage *twoside = twoside_stage(stage);
+
+   if (header->det * twoside->facing < 0) {
+      struct prim_header tmp;
+
+      tmp.det = header->det;
+      tmp.v[0] = copy_bfc(twoside, header->v[0], 0);
+      tmp.v[1] = copy_bfc(twoside, header->v[1], 1);
+      tmp.v[2] = copy_bfc(twoside, header->v[2], 2);
+
+      stage->next->tri( stage->next, &tmp );
+   }
+   else {
+      stage->next->tri( stage->next, header );
+   }
+}
+
+
+static void twoside_line( struct prim_stage *stage,
+		       struct prim_header *header )
+{
+   stage->next->line( stage->next, header );
+}
+
+
+static void twoside_point( struct prim_stage *stage,
+			struct prim_header *header )
+{
+   stage->next->point( stage->next, header );
+}
+
+static void twoside_end( struct prim_stage *stage )
+{
+   stage->next->end( stage->next );
+}
+
+
+
+struct prim_stage *prim_twoside( struct softpipe_context *softpipe )
+{
+   struct twoside_stage *twoside = CALLOC_STRUCT(twoside_stage);
+
+   prim_alloc_tmps( &twoside->stage, 3 );
+
+   twoside->stage.softpipe = softpipe;
+   twoside->stage.next = NULL;
+   twoside->stage.begin = twoside_begin;
+   twoside->stage.point = twoside_point;
+   twoside->stage.line = twoside_line;
+   twoside->stage.tri = twoside_tri;
+   twoside->stage.end = twoside_end;
+
+   twoside->lookup = softpipe->vf_attr_to_slot;
+
+   return &twoside->stage;
+}