1 /**************************************************************************
3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 **************************************************************************/
28 /* Authors: Keith Whitwell <keith@tungstengraphics.com>
31 #include "pipe/p_util.h"
32 #include "pipe/p_defines.h"
33 #include "pipe/p_shader_tokens.h"
35 #include "draw_pipe.h"
37 struct twoside_stage
{
38 struct draw_stage stage
;
39 float sign
; /**< +1 or -1 */
40 uint attrib_front0
, attrib_back0
;
41 uint attrib_front1
, attrib_back1
;
45 static INLINE
struct twoside_stage
*twoside_stage( struct draw_stage
*stage
)
47 return (struct twoside_stage
*)stage
;
54 * Copy back color(s) to front color(s).
56 static INLINE
struct vertex_header
*
57 copy_bfc( struct twoside_stage
*twoside
,
58 const struct vertex_header
*v
,
61 struct vertex_header
*tmp
= dup_vert( &twoside
->stage
, v
, idx
);
63 if (twoside
->attrib_back0
) {
64 COPY_4FV(tmp
->data
[twoside
->attrib_front0
],
65 tmp
->data
[twoside
->attrib_back0
]);
67 if (twoside
->attrib_back1
) {
68 COPY_4FV(tmp
->data
[twoside
->attrib_front1
],
69 tmp
->data
[twoside
->attrib_back1
]);
78 static void twoside_tri( struct draw_stage
*stage
,
79 struct prim_header
*header
)
81 struct twoside_stage
*twoside
= twoside_stage(stage
);
83 if (header
->det
* twoside
->sign
< 0.0) {
84 /* this is a back-facing triangle */
85 struct prim_header tmp
;
87 tmp
.det
= header
->det
;
88 tmp
.edgeflags
= header
->edgeflags
;
89 /* copy back attribs to front attribs */
90 tmp
.v
[0] = copy_bfc(twoside
, header
->v
[0], 0);
91 tmp
.v
[1] = copy_bfc(twoside
, header
->v
[1], 1);
92 tmp
.v
[2] = copy_bfc(twoside
, header
->v
[2], 2);
94 stage
->next
->tri( stage
->next
, &tmp
);
97 stage
->next
->tri( stage
->next
, header
);
102 static void twoside_line( struct draw_stage
*stage
,
103 struct prim_header
*header
)
106 stage
->next
->line( stage
->next
, header
);
110 static void twoside_point( struct draw_stage
*stage
,
111 struct prim_header
*header
)
114 stage
->next
->point( stage
->next
, header
);
118 static void twoside_first_tri( struct draw_stage
*stage
,
119 struct prim_header
*header
)
121 struct twoside_stage
*twoside
= twoside_stage(stage
);
122 const struct draw_vertex_shader
*vs
= stage
->draw
->vertex_shader
;
125 twoside
->attrib_front0
= 0;
126 twoside
->attrib_front1
= 0;
127 twoside
->attrib_back0
= 0;
128 twoside
->attrib_back1
= 0;
130 /* Find which vertex shader outputs are front/back colors */
131 for (i
= 0; i
< vs
->info
.num_outputs
; i
++) {
132 if (vs
->info
.output_semantic_name
[i
] == TGSI_SEMANTIC_COLOR
) {
133 if (vs
->info
.output_semantic_index
[i
] == 0)
134 twoside
->attrib_front0
= i
;
136 twoside
->attrib_front1
= i
;
138 if (vs
->info
.output_semantic_name
[i
] == TGSI_SEMANTIC_BCOLOR
) {
139 if (vs
->info
.output_semantic_index
[i
] == 0)
140 twoside
->attrib_back0
= i
;
142 twoside
->attrib_back1
= i
;
146 if (!twoside
->attrib_back0
)
147 twoside
->attrib_front0
= 0;
149 if (!twoside
->attrib_back1
)
150 twoside
->attrib_front1
= 0;
153 * We'll multiply the primitive's determinant by this sign to determine
154 * if the triangle is back-facing (negative).
155 * sign = -1 for CCW, +1 for CW
157 twoside
->sign
= (stage
->draw
->rasterizer
->front_winding
== PIPE_WINDING_CCW
) ? -1.0f
: 1.0f
;
159 stage
->tri
= twoside_tri
;
160 stage
->tri( stage
, header
);
164 static void twoside_flush( struct draw_stage
*stage
, unsigned flags
)
166 stage
->tri
= twoside_first_tri
;
167 stage
->next
->flush( stage
->next
, flags
);
171 static void twoside_reset_stipple_counter( struct draw_stage
*stage
)
173 stage
->next
->reset_stipple_counter( stage
->next
);
177 static void twoside_destroy( struct draw_stage
*stage
)
179 draw_free_temp_verts( stage
);
185 * Create twoside pipeline stage.
187 struct draw_stage
*draw_twoside_stage( struct draw_context
*draw
)
189 struct twoside_stage
*twoside
= CALLOC_STRUCT(twoside_stage
);
191 draw_alloc_temp_verts( &twoside
->stage
, 3 );
193 twoside
->stage
.draw
= draw
;
194 twoside
->stage
.next
= NULL
;
195 twoside
->stage
.point
= twoside_point
;
196 twoside
->stage
.line
= twoside_line
;
197 twoside
->stage
.tri
= twoside_first_tri
;
198 twoside
->stage
.flush
= twoside_flush
;
199 twoside
->stage
.reset_stipple_counter
= twoside_reset_stipple_counter
;
200 twoside
->stage
.destroy
= twoside_destroy
;
202 return &twoside
->stage
;