src/gallium/auxiliary/draw/draw_pipe_unfilled.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 /**
  29  * \brief  Drawing stage for handling glPolygonMode(line/point).
  30  * Convert triangles to points or lines as needed.
  31  */
  32
  33 /* Authors:  Keith Whitwell <keith@tungstengraphics.com>
  34  */
  35
  36 #include "util/u_memory.h"
  37 #include "pipe/p_defines.h"
  38 #include "draw_private.h"
  39 #include "draw_pipe.h"
  40 #include "draw_fs.h"
  41
  42
  43 struct unfilled_stage {
  44    struct draw_stage stage;
  45
  46    /** [0] = front face, [1] = back face.
  47     * legal values:  PIPE_POLYGON_MODE_FILL, PIPE_POLYGON_MODE_LINE,
  48     * and PIPE_POLYGON_MODE_POINT,
  49     */
  50    unsigned mode[2];
  51
  52    int face_slot;
  53 };
  54
  55
  56 static INLINE struct unfilled_stage *unfilled_stage( struct draw_stage *stage )
  57 {
  58    return (struct unfilled_stage *)stage;
  59 }
  60
  61 static void
  62 inject_front_face_info(struct draw_stage *stage,
  63                        struct prim_header *header)
  64 {
  65    struct unfilled_stage *unfilled = unfilled_stage(stage);
  66    unsigned ccw = header->det < 0.0;
  67    boolean is_front_face = (
  68       (stage->draw->rasterizer->front_ccw && ccw) ||
  69       (!stage->draw->rasterizer->front_ccw && !ccw));
  70    int slot = unfilled->face_slot;
  71    unsigned i;
  72
  73    /* In case the backend doesn't care about it */
  74    if (slot < 0) {
  75       return;
  76    }
  77
  78    for (i = 0; i < 3; ++i) {
  79       struct vertex_header *v = header->v[i];
  80       v->data[slot][0] = is_front_face;
  81       v->data[slot][1] = is_front_face;
  82       v->data[slot][2] = is_front_face;
  83       v->data[slot][3] = is_front_face;
  84       v->vertex_id = UNDEFINED_VERTEX_ID;
  85    }
  86 }
  87
  88
  89 static void point( struct draw_stage *stage,
  90                    struct vertex_header *v0 )
  91 {
  92    struct prim_header tmp;
  93    tmp.v[0] = v0;
  94    stage->next->point( stage->next, &tmp );
  95 }
  96
  97 static void line( struct draw_stage *stage,
  98                   struct vertex_header *v0,
  99                   struct vertex_header *v1 )
 100 {
 101    struct prim_header tmp;
 102    tmp.v[0] = v0;
 103    tmp.v[1] = v1;
 104    stage->next->line( stage->next, &tmp );
 105 }
 106
 107
 108 static void points( struct draw_stage *stage,
 109                     struct prim_header *header )
 110 {
 111    struct vertex_header *v0 = header->v[0];
 112    struct vertex_header *v1 = header->v[1];
 113    struct vertex_header *v2 = header->v[2];
 114
 115    inject_front_face_info(stage, header);
 116
 117    if ((header->flags & DRAW_PIPE_EDGE_FLAG_0) && v0->edgeflag) point( stage, v0 );
 118    if ((header->flags & DRAW_PIPE_EDGE_FLAG_1) && v1->edgeflag) point( stage, v1 );
 119    if ((header->flags & DRAW_PIPE_EDGE_FLAG_2) && v2->edgeflag) point( stage, v2 );
 120 }
 121
 122
 123 static void lines( struct draw_stage *stage,
 124                    struct prim_header *header )
 125 {
 126    struct vertex_header *v0 = header->v[0];
 127    struct vertex_header *v1 = header->v[1];
 128    struct vertex_header *v2 = header->v[2];
 129
 130    if (header->flags & DRAW_PIPE_RESET_STIPPLE)
 131       stage->next->reset_stipple_counter( stage->next );
 132
 133    inject_front_face_info(stage, header);
 134
 135    if ((header->flags & DRAW_PIPE_EDGE_FLAG_2) && v2->edgeflag) line( stage, v2, v0 );
 136    if ((header->flags & DRAW_PIPE_EDGE_FLAG_0) && v0->edgeflag) line( stage, v0, v1 );
 137    if ((header->flags & DRAW_PIPE_EDGE_FLAG_1) && v1->edgeflag) line( stage, v1, v2 );
 138 }
 139
 140
 141 /** For debugging */
 142 static void
 143 print_header_flags(unsigned flags)
 144 {
 145    debug_printf("header->flags = ");
 146    if (flags & DRAW_PIPE_RESET_STIPPLE)
 147       debug_printf("RESET_STIPPLE ");
 148    if (flags & DRAW_PIPE_EDGE_FLAG_0)
 149       debug_printf("EDGE_FLAG_0 ");
 150    if (flags & DRAW_PIPE_EDGE_FLAG_1)
 151       debug_printf("EDGE_FLAG_1 ");
 152    if (flags & DRAW_PIPE_EDGE_FLAG_2)
 153       debug_printf("EDGE_FLAG_2 ");
 154    debug_printf("\n");
 155 }
 156
 157
 158 /* Unfilled tri:
 159  *
 160  * Note edgeflags in the vertex struct is not sufficient as we will
 161  * need to manipulate them when decomposing primitives.
 162  *
 163  * We currently keep the vertex edgeflag and primitive edgeflag mask
 164  * separate until the last possible moment.
 165  */
 166 static void unfilled_tri( struct draw_stage *stage,
 167                           struct prim_header *header )
 168 {
 169    struct unfilled_stage *unfilled = unfilled_stage(stage);
 170    unsigned cw = header->det >= 0.0;
 171    unsigned mode = unfilled->mode[cw];
 172
 173    if (0)
 174       print_header_flags(header->flags);
 175
 176    switch (mode) {
 177    case PIPE_POLYGON_MODE_FILL:
 178       stage->next->tri( stage->next, header );
 179       break;
 180    case PIPE_POLYGON_MODE_LINE:
 181       lines( stage, header );
 182       break;
 183    case PIPE_POLYGON_MODE_POINT:
 184       points( stage, header );
 185       break;
 186    default:
 187       assert(0);
 188    }
 189 }
 190
 191
 192 static void unfilled_first_tri( struct draw_stage *stage,
 193                                 struct prim_header *header )
 194 {
 195    struct unfilled_stage *unfilled = unfilled_stage(stage);
 196    const struct pipe_rasterizer_state *rast = stage->draw->rasterizer;
 197
 198    unfilled->mode[0] = rast->front_ccw ? rast->fill_front : rast->fill_back;
 199    unfilled->mode[1] = rast->front_ccw ? rast->fill_back : rast->fill_front;
 200
 201    stage->tri = unfilled_tri;
 202    stage->tri( stage, header );
 203 }
 204
 205
 206
 207 static void unfilled_flush( struct draw_stage *stage,
 208                             unsigned flags )
 209 {
 210    stage->next->flush( stage->next, flags );
 211
 212    stage->tri = unfilled_first_tri;
 213 }
 214
 215
 216 static void unfilled_reset_stipple_counter( struct draw_stage *stage )
 217 {
 218    stage->next->reset_stipple_counter( stage->next );
 219 }
 220
 221
 222 static void unfilled_destroy( struct draw_stage *stage )
 223 {
 224    draw_free_temp_verts( stage );
 225    FREE( stage );
 226 }
 227
 228 /*
 229  * Try to allocate an output slot which we can use
 230  * to preserve the front face information.
 231  */
 232 void
 233 draw_unfilled_prepare_outputs( struct draw_context *draw,
 234                                struct draw_stage *stage )
 235 {
 236    struct unfilled_stage *unfilled = unfilled_stage(stage);
 237    const struct pipe_rasterizer_state *rast = draw ? draw->rasterizer : 0;
 238    boolean is_unfilled = (rast &&
 239                           (rast->fill_front != PIPE_POLYGON_MODE_FILL ||
 240                            rast->fill_back != PIPE_POLYGON_MODE_FILL));
 241    const struct draw_fragment_shader *fs = draw ? draw->fs.fragment_shader : 0;
 242
 243    if (is_unfilled && fs && fs->info.uses_frontface)  {
 244       unfilled->face_slot = draw_alloc_extra_vertex_attrib(
 245          stage->draw, TGSI_SEMANTIC_FACE, 0);
 246    } else {
 247       unfilled->face_slot = -1;
 248    }
 249 }
 250
 251
 252 /**
 253  * Create unfilled triangle stage.
 254  */
 255 struct draw_stage *draw_unfilled_stage( struct draw_context *draw )
 256 {
 257    struct unfilled_stage *unfilled = CALLOC_STRUCT(unfilled_stage);
 258    if (unfilled == NULL)
 259       goto fail;
 260
 261    unfilled->stage.draw = draw;
 262    unfilled->stage.name = "unfilled";
 263    unfilled->stage.next = NULL;
 264    unfilled->stage.tmp = NULL;
 265    unfilled->stage.point = draw_pipe_passthrough_point;
 266    unfilled->stage.line = draw_pipe_passthrough_line;
 267    unfilled->stage.tri = unfilled_first_tri;
 268    unfilled->stage.flush = unfilled_flush;
 269    unfilled->stage.reset_stipple_counter = unfilled_reset_stipple_counter;
 270    unfilled->stage.destroy = unfilled_destroy;
 271
 272    unfilled->face_slot = -1;
 273
 274    if (!draw_alloc_temp_verts( &unfilled->stage, 0 ))
 275       goto fail;
 276
 277    return &unfilled->stage;
 278
 279  fail:
 280    if (unfilled)
 281       unfilled->stage.destroy( &unfilled->stage );
 282
 283    return NULL;
 284 }