diff options
Diffstat (limited to 'src/gallium/aux/draw/draw_twoside.c')
| -rw-r--r-- | src/gallium/aux/draw/draw_twoside.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/src/gallium/aux/draw/draw_twoside.c b/src/gallium/aux/draw/draw_twoside.c new file mode 100644 index 00000000000..1c389579871 --- /dev/null +++ b/src/gallium/aux/draw/draw_twoside.c @@ -0,0 +1,203 @@ +/************************************************************************** + * + * 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 "pipe/p_util.h" +#include "pipe/p_defines.h" +#include "pipe/p_shader_tokens.h" +#include "draw_private.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.edgeflags = header->edgeflags; + /* 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_line( struct draw_stage *stage, + struct prim_header *header ) +{ + /* pass-through */ + stage->next->line( stage->next, header ); +} + + +static void twoside_point( struct draw_stage *stage, + struct prim_header *header ) +{ + /* pass-through */ + stage->next->point( 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 pipe_shader_state *vs = stage->draw->vertex_shader->state; + 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->num_outputs; i++) { + if (vs->output_semantic_name[i] == TGSI_SEMANTIC_COLOR) { + if (vs->output_semantic_index[i] == 0) + twoside->attrib_front0 = i; + else + twoside->attrib_front1 = i; + } + if (vs->output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) { + if (vs->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); + + draw_alloc_temp_verts( &twoside->stage, 3 ); + + twoside->stage.draw = draw; + twoside->stage.next = NULL; + twoside->stage.point = twoside_point; + twoside->stage.line = twoside_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; +} |