src/mesa/pipe/draw/draw_flatshade.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   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:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  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.
  25  *
  26  **************************************************************************/
  27
  28 /* Authors:  Keith Whitwell <keith@tungstengraphics.com>
  29  */
  30
  31 #include "pipe/p_util.h"
  32 #include "pipe/p_shader_tokens.h"
  33 #include "draw_private.h"
  34
  35
  36 /** subclass of draw_stage */
  37 struct flat_stage
  38 {
  39    struct draw_stage stage;
  40
  41    uint num_color_attribs;
  42    uint color_attribs[4];  /* front/back primary/secondary colors */
  43 };
  44
  45
  46 static INLINE struct flat_stage *
  47 flat_stage(struct draw_stage *stage)
  48 {
  49    return (struct flat_stage *) stage;
  50 }
  51
  52
  53 static void flatshade_begin( struct draw_stage *stage )
  54 {
  55    struct flat_stage *flat = flat_stage(stage);
  56    const struct pipe_shader_state *vs = stage->draw->vertex_shader->state;
  57    uint i;
  58
  59    /* Find which vertex shader outputs are colors, make a list */
  60    flat->num_color_attribs = 0;
  61    for (i = 0; i < vs->num_outputs; i++) {
  62       if (vs->output_semantic_name[i] == TGSI_SEMANTIC_COLOR ||
  63           vs->output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) {
  64          flat->color_attribs[flat->num_color_attribs++] = i;
  65       }
  66    }
  67
  68    stage->next->begin( stage->next );
  69 }
  70
  71
  72 /** Copy all the color attributes from 'src' vertex to 'dst' vertex */
  73 static INLINE void copy_colors( struct draw_stage *stage,
  74                                 struct vertex_header *dst,
  75                                 const struct vertex_header *src )
  76 {
  77    const struct flat_stage *flat = flat_stage(stage);
  78    uint i;
  79
  80    /* Look for constant/flat attribs and duplicate from src to dst vertex */
  81    /* skip attrib[0] which is vert pos */
  82    for (i = 0; i < flat->num_color_attribs; i++) {
  83       const uint attr = flat->color_attribs[i];
  84       memcpy(dst->data[attr], src->data[attr], sizeof(src->data[0]));
  85    }
  86 }
  87
  88
  89 /**
  90  * Flatshade tri.  Required for clipping and when unfilled tris are
  91  * active, otherwise handled by hardware.
  92  */
  93 static void flatshade_tri( struct draw_stage *stage,
  94                            struct prim_header *header )
  95 {
  96    struct prim_header tmp;
  97
  98    tmp.det = header->det;
  99    tmp.edgeflags = header->edgeflags;
 100    tmp.v[0] = dup_vert(stage, header->v[0], 0);
 101    tmp.v[1] = dup_vert(stage, header->v[1], 1);
 102    tmp.v[2] = header->v[2];
 103
 104    copy_colors(stage, tmp.v[0], tmp.v[2]);
 105    copy_colors(stage, tmp.v[1], tmp.v[2]);
 106
 107    stage->next->tri( stage->next, &tmp );
 108 }
 109
 110
 111 /**
 112  * Flatshade line.  Required for clipping.
 113  */
 114 static void flatshade_line( struct draw_stage *stage,
 115                             struct prim_header *header )
 116 {
 117    struct prim_header tmp;
 118
 119    tmp.v[0] = dup_vert(stage, header->v[0], 0);
 120    tmp.v[1] = header->v[1];
 121
 122    copy_colors(stage, tmp.v[0], tmp.v[1]);
 123
 124    stage->next->line( stage->next, &tmp );
 125 }
 126
 127
 128 static void flatshade_point( struct draw_stage *stage,
 129                              struct prim_header *header )
 130 {
 131    stage->next->point( stage->next, header );
 132 }
 133
 134
 135 static void flatshade_end( struct draw_stage *stage )
 136 {
 137    stage->next->end( stage->next );
 138 }
 139
 140
 141 static void flatshade_reset_stipple_counter( struct draw_stage *stage )
 142 {
 143    stage->next->reset_stipple_counter( stage->next );
 144 }
 145
 146
 147 static void flatshade_destroy( struct draw_stage *stage )
 148 {
 149    draw_free_tmps( stage );
 150    FREE( stage );
 151 }
 152
 153
 154 /**
 155  * Create flatshading drawing stage.
 156  */
 157 struct draw_stage *draw_flatshade_stage( struct draw_context *draw )
 158 {
 159    struct flat_stage *flatshade = CALLOC_STRUCT(flat_stage);
 160
 161    draw_alloc_tmps( &flatshade->stage, 2 );
 162
 163    flatshade->stage.draw = draw;
 164    flatshade->stage.next = NULL;
 165    flatshade->stage.begin = flatshade_begin;
 166    flatshade->stage.point = flatshade_point;
 167    flatshade->stage.line = flatshade_line;
 168    flatshade->stage.tri = flatshade_tri;
 169    flatshade->stage.end = flatshade_end;
 170    flatshade->stage.reset_stipple_counter = flatshade_reset_stipple_counter;
 171    flatshade->stage.destroy = flatshade_destroy;
 172
 173    return &flatshade->stage;
 174 }
 175
 176