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Diffstat (limited to 'src/gallium/auxiliary/draw/draw_pipe_twoside.c')
-rw-r--r--src/gallium/auxiliary/draw/draw_pipe_twoside.c200
1 files changed, 200 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/draw/draw_pipe_twoside.c b/src/gallium/auxiliary/draw/draw_pipe_twoside.c
new file mode 100644
index 0000000000..eef0238b15
--- /dev/null
+++ b/src/gallium/auxiliary/draw/draw_pipe_twoside.c
@@ -0,0 +1,200 @@
+/**************************************************************************
+ *
+ * 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 <keith@tungstengraphics.com>
+ */
+
+#include "util/u_math.h"
+#include "util/u_memory.h"
+#include "pipe/p_defines.h"
+#include "pipe/p_shader_tokens.h"
+#include "draw_vs.h"
+#include "draw_pipe.h"
+
+struct twoside_stage {
+ struct draw_stage stage;
+ float sign; /**< +1 or -1 */
+ uint attrib_front0, attrib_back0;
+ uint attrib_front1, attrib_back1;
+};
+
+
+static INLINE struct twoside_stage *twoside_stage( struct draw_stage *stage )
+{
+ return (struct twoside_stage *)stage;
+}
+
+
+
+
+/**
+ * Copy back color(s) to front color(s).
+ */
+static INLINE struct vertex_header *
+copy_bfc( struct twoside_stage *twoside,
+ const struct vertex_header *v,
+ unsigned idx )
+{
+ struct vertex_header *tmp = dup_vert( &twoside->stage, v, idx );
+
+ if (twoside->attrib_back0) {
+ COPY_4FV(tmp->data[twoside->attrib_front0],
+ tmp->data[twoside->attrib_back0]);
+ }
+ if (twoside->attrib_back1) {
+ COPY_4FV(tmp->data[twoside->attrib_front1],
+ tmp->data[twoside->attrib_back1]);
+ }
+
+ return tmp;
+}
+
+
+/* Twoside tri:
+ */
+static void twoside_tri( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ struct twoside_stage *twoside = twoside_stage(stage);
+
+ if (header->det * twoside->sign < 0.0) {
+ /* this is a back-facing triangle */
+ struct prim_header tmp;
+
+ tmp.det = header->det;
+ tmp.flags = header->flags;
+ tmp.pad = header->pad;
+ /* copy back attribs to front attribs */
+ 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_first_tri( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ struct twoside_stage *twoside = twoside_stage(stage);
+ const struct draw_vertex_shader *vs = stage->draw->vs.vertex_shader;
+ uint i;
+
+ twoside->attrib_front0 = 0;
+ twoside->attrib_front1 = 0;
+ twoside->attrib_back0 = 0;
+ twoside->attrib_back1 = 0;
+
+ /* Find which vertex shader outputs are front/back colors */
+ for (i = 0; i < vs->info.num_outputs; i++) {
+ if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_COLOR) {
+ if (vs->info.output_semantic_index[i] == 0)
+ twoside->attrib_front0 = i;
+ else
+ twoside->attrib_front1 = i;
+ }
+ if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) {
+ if (vs->info.output_semantic_index[i] == 0)
+ twoside->attrib_back0 = i;
+ else
+ twoside->attrib_back1 = i;
+ }
+ }
+
+ if (!twoside->attrib_back0)
+ twoside->attrib_front0 = 0;
+
+ if (!twoside->attrib_back1)
+ twoside->attrib_front1 = 0;
+
+ /*
+ * We'll multiply the primitive's determinant by this sign to determine
+ * if the triangle is back-facing (negative).
+ * sign = -1 for CCW, +1 for CW
+ */
+ twoside->sign = (stage->draw->rasterizer->front_winding == PIPE_WINDING_CCW) ? -1.0f : 1.0f;
+
+ stage->tri = twoside_tri;
+ stage->tri( stage, header );
+}
+
+
+static void twoside_flush( struct draw_stage *stage, unsigned flags )
+{
+ stage->tri = twoside_first_tri;
+ stage->next->flush( stage->next, flags );
+}
+
+
+static void twoside_reset_stipple_counter( struct draw_stage *stage )
+{
+ stage->next->reset_stipple_counter( stage->next );
+}
+
+
+static void twoside_destroy( struct draw_stage *stage )
+{
+ draw_free_temp_verts( stage );
+ FREE( stage );
+}
+
+
+/**
+ * Create twoside pipeline stage.
+ */
+struct draw_stage *draw_twoside_stage( struct draw_context *draw )
+{
+ struct twoside_stage *twoside = CALLOC_STRUCT(twoside_stage);
+ if (twoside == NULL)
+ goto fail;
+
+ if (!draw_alloc_temp_verts( &twoside->stage, 3 ))
+ goto fail;
+
+ twoside->stage.draw = draw;
+ twoside->stage.name = "twoside";
+ twoside->stage.next = NULL;
+ twoside->stage.point = draw_pipe_passthrough_point;
+ twoside->stage.line = draw_pipe_passthrough_line;
+ twoside->stage.tri = twoside_first_tri;
+ twoside->stage.flush = twoside_flush;
+ twoside->stage.reset_stipple_counter = twoside_reset_stipple_counter;
+ twoside->stage.destroy = twoside_destroy;
+
+ return &twoside->stage;
+
+ fail:
+ if (twoside)
+ twoside->stage.destroy( &twoside->stage );
+
+ return NULL;
+}