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    }
  85 }
  86
  87
  88 static void point( struct draw_stage *stage,
  89                    struct vertex_header *v0 )
  90 {
  91    struct prim_header tmp;
  92    tmp.v[0] = v0;
  93    stage->next->point( stage->next, &tmp );
  94 }
  95
  96 static void line( struct draw_stage *stage,
  97                   struct vertex_header *v0,
  98                   struct vertex_header *v1 )
  99 {
 100    struct prim_header tmp;
 101    tmp.v[0] = v0;
 102    tmp.v[1] = v1;
 103    stage->next->line( stage->next, &tmp );
 104 }
 105
 106
 107 static void points( struct draw_stage *stage,
 108                     struct prim_header *header )
 109 {
 110    struct vertex_header *v0 = header->v[0];
 111    struct vertex_header *v1 = header->v[1];
 112    struct vertex_header *v2 = header->v[2];
 113
 114    inject_front_face_info(stage, header);
 115
 116    if ((header->flags & DRAW_PIPE_EDGE_FLAG_0) && v0->edgeflag) point( stage, v0 );
 117    if ((header->flags & DRAW_PIPE_EDGE_FLAG_1) && v1->edgeflag) point( stage, v1 );
 118    if ((header->flags & DRAW_PIPE_EDGE_FLAG_2) && v2->edgeflag) point( stage, v2 );
 119 }
 120
 121
 122 static void lines( struct draw_stage *stage,
 123                    struct prim_header *header )
 124 {
 125    struct vertex_header *v0 = header->v[0];
 126    struct vertex_header *v1 = header->v[1];
 127    struct vertex_header *v2 = header->v[2];
 128
 129    if (header->flags & DRAW_PIPE_RESET_STIPPLE)
 130       stage->next->reset_stipple_counter( stage->next );
 131
 132    inject_front_face_info(stage, header);
 133
 134    if ((header->flags & DRAW_PIPE_EDGE_FLAG_2) && v2->edgeflag) line( stage, v2, v0 );
 135    if ((header->flags & DRAW_PIPE_EDGE_FLAG_0) && v0->edgeflag) line( stage, v0, v1 );
 136    if ((header->flags & DRAW_PIPE_EDGE_FLAG_1) && v1->edgeflag) line( stage, v1, v2 );
 137 }
 138
 139
 140 /** For debugging */
 141 static void
 142 print_header_flags(unsigned flags)
 143 {
 144    debug_printf("header->flags = ");
 145    if (flags & DRAW_PIPE_RESET_STIPPLE)
 146       debug_printf("RESET_STIPPLE ");
 147    if (flags & DRAW_PIPE_EDGE_FLAG_0)
 148       debug_printf("EDGE_FLAG_0 ");
 149    if (flags & DRAW_PIPE_EDGE_FLAG_1)
 150       debug_printf("EDGE_FLAG_1 ");
 151    if (flags & DRAW_PIPE_EDGE_FLAG_2)
 152       debug_printf("EDGE_FLAG_2 ");
 153    debug_printf("\n");
 154 }
 155
 156
 157 /* Unfilled tri:
 158  *
 159  * Note edgeflags in the vertex struct is not sufficient as we will
 160  * need to manipulate them when decomposing primitives.
 161  *
 162  * We currently keep the vertex edgeflag and primitive edgeflag mask
 163  * separate until the last possible moment.
 164  */
 165 static void unfilled_tri( struct draw_stage *stage,
 166                           struct prim_header *header )
 167 {
 168    struct unfilled_stage *unfilled = unfilled_stage(stage);
 169    unsigned cw = header->det >= 0.0;
 170    unsigned mode = unfilled->mode[cw];
 171
 172    if (0)
 173       print_header_flags(header->flags);
 174
 175    switch (mode) {
 176    case PIPE_POLYGON_MODE_FILL:
 177       stage->next->tri( stage->next, header );
 178       break;
 179    case PIPE_POLYGON_MODE_LINE:
 180       lines( stage, header );
 181       break;
 182    case PIPE_POLYGON_MODE_POINT:
 183       points( stage, header );
 184       break;
 185    default:
 186       assert(0);
 187    }
 188 }
 189
 190
 191 static void unfilled_first_tri( struct draw_stage *stage,
 192                                 struct prim_header *header )
 193 {
 194    struct unfilled_stage *unfilled = unfilled_stage(stage);
 195    const struct pipe_rasterizer_state *rast = stage->draw->rasterizer;
 196
 197    unfilled->mode[0] = rast->front_ccw ? rast->fill_front : rast->fill_back;
 198    unfilled->mode[1] = rast->front_ccw ? rast->fill_back : rast->fill_front;
 199
 200    stage->tri = unfilled_tri;
 201    stage->tri( stage, header );
 202 }
 203
 204
 205
 206 static void unfilled_flush( struct draw_stage *stage,
 207                             unsigned flags )
 208 {
 209    stage->next->flush( stage->next, flags );
 210
 211    stage->tri = unfilled_first_tri;
 212 }
 213
 214
 215 static void unfilled_reset_stipple_counter( struct draw_stage *stage )
 216 {
 217    stage->next->reset_stipple_counter( stage->next );
 218 }
 219
 220
 221 static void unfilled_destroy( struct draw_stage *stage )
 222 {
 223    draw_free_temp_verts( stage );
 224    FREE( stage );
 225 }
 226
 227 /*
 228  * Try to allocate an output slot which we can use
 229  * to preserve the front face information.
 230  */
 231 void
 232 draw_unfilled_prepare_outputs( struct draw_context *draw,
 233                                struct draw_stage *stage )
 234 {
 235    struct unfilled_stage *unfilled = unfilled_stage(stage);
 236    const struct pipe_rasterizer_state *rast = draw ? draw->rasterizer : 0;
 237    boolean is_unfilled = (rast &&
 238                           (rast->fill_front != PIPE_POLYGON_MODE_FILL ||
 239                            rast->fill_back != PIPE_POLYGON_MODE_FILL));
 240    const struct draw_fragment_shader *fs = draw->fs.fragment_shader;
 241
 242    if (is_unfilled && fs && fs->info.uses_frontface)  {
 243       unfilled->face_slot = draw_alloc_extra_vertex_attrib(
 244          stage->draw, TGSI_SEMANTIC_FACE, 0);
 245    } else {
 246       unfilled->face_slot = -1;
 247    }
 248 }
 249
 250
 251 /**
 252  * Create unfilled triangle stage.
 253  */
 254 struct draw_stage *draw_unfilled_stage( struct draw_context *draw )
 255 {
 256    struct unfilled_stage *unfilled = CALLOC_STRUCT(unfilled_stage);
 257    if (unfilled == NULL)
 258       goto fail;
 259
 260    unfilled->stage.draw = draw;
 261    unfilled->stage.name = "unfilled";
 262    unfilled->stage.next = NULL;
 263    unfilled->stage.tmp = NULL;
 264    unfilled->stage.point = draw_pipe_passthrough_point;
 265    unfilled->stage.line = draw_pipe_passthrough_line;
 266    unfilled->stage.tri = unfilled_first_tri;
 267    unfilled->stage.flush = unfilled_flush;
 268    unfilled->stage.reset_stipple_counter = unfilled_reset_stipple_counter;
 269    unfilled->stage.destroy = unfilled_destroy;
 270
 271    if (!draw_alloc_temp_verts( &unfilled->stage, 0 ))
 272       goto fail;
 273
 274    return &unfilled->stage;
 275
 276  fail:
 277    if (unfilled)
 278       unfilled->stage.destroy( &unfilled->stage );
 279
 280    return NULL;
 281 }