src/gallium/aux/draw/draw_wide_prims.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_defines.h"
  33 #include "pipe/p_shader_tokens.h"
  34 #include "draw_private.h"
  35
  36
  37 struct wide_stage {
  38    struct draw_stage stage;
  39
  40    float half_line_width;
  41    float half_point_size;
  42
  43    uint texcoord_slot[PIPE_MAX_SHADER_OUTPUTS];
  44    uint texcoord_mode[PIPE_MAX_SHADER_OUTPUTS];
  45    uint num_texcoords;
  46
  47    int psize_slot;
  48 };
  49
  50
  51
  52 static INLINE struct wide_stage *wide_stage( struct draw_stage *stage )
  53 {
  54    return (struct wide_stage *)stage;
  55 }
  56
  57
  58 static void passthrough_point( struct draw_stage *stage,
  59                                struct prim_header *header )
  60 {
  61    stage->next->point( stage->next, header );
  62 }
  63
  64 static void passthrough_line( struct draw_stage *stage,
  65                               struct prim_header *header )
  66 {
  67    stage->next->line(stage->next, header);
  68 }
  69
  70 static void passthrough_tri( struct draw_stage *stage,
  71                              struct prim_header *header )
  72 {
  73    stage->next->tri(stage->next, header);
  74 }
  75
  76
  77 /**
  78  * Draw a wide line by drawing a quad (two triangles).
  79  * XXX need to disable polygon stipple.
  80  */
  81 static void wide_line( struct draw_stage *stage,
  82                        struct prim_header *header )
  83 {
  84    const struct wide_stage *wide = wide_stage(stage);
  85    const float half_width = wide->half_line_width;
  86
  87    struct prim_header tri;
  88
  89    struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
  90    struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
  91    struct vertex_header *v2 = dup_vert(stage, header->v[1], 2);
  92    struct vertex_header *v3 = dup_vert(stage, header->v[1], 3);
  93
  94    float *pos0 = v0->data[0];
  95    float *pos1 = v1->data[0];
  96    float *pos2 = v2->data[0];
  97    float *pos3 = v3->data[0];
  98
  99    const float dx = FABSF(pos0[0] - pos2[0]);
 100    const float dy = FABSF(pos0[1] - pos2[1]);
 101
 102    /*
 103     * Draw wide line as a quad (two tris) by "stretching" the line along
 104     * X or Y.
 105     * We need to tweak coords in several ways to be conformant here.
 106     */
 107
 108    if (dx > dy) {
 109       /* x-major line */
 110       pos0[1] = pos0[1] - half_width - 0.25f;
 111       pos1[1] = pos1[1] + half_width - 0.25f;
 112       pos2[1] = pos2[1] - half_width - 0.25f;
 113       pos3[1] = pos3[1] + half_width - 0.25f;
 114       if (pos0[0] < pos2[0]) {
 115          /* left to right line */
 116          pos0[0] -= 0.5f;
 117          pos1[0] -= 0.5f;
 118          pos2[0] -= 0.5f;
 119          pos3[0] -= 0.5f;
 120       }
 121       else {
 122          /* right to left line */
 123          pos0[0] += 0.5f;
 124          pos1[0] += 0.5f;
 125          pos2[0] += 0.5f;
 126          pos3[0] += 0.5f;
 127       }
 128    }
 129    else {
 130       /* y-major line */
 131       pos0[0] = pos0[0] - half_width + 0.25f;
 132       pos1[0] = pos1[0] + half_width + 0.25f;
 133       pos2[0] = pos2[0] - half_width + 0.25f;
 134       pos3[0] = pos3[0] + half_width + 0.25f;
 135       if (pos0[1] < pos2[1]) {
 136          /* top to bottom line */
 137          pos0[1] -= 0.5f;
 138          pos1[1] -= 0.5f;
 139          pos2[1] -= 0.5f;
 140          pos3[1] -= 0.5f;
 141       }
 142       else {
 143          /* bottom to top line */
 144          pos0[1] += 0.5f;
 145          pos1[1] += 0.5f;
 146          pos2[1] += 0.5f;
 147          pos3[1] += 0.5f;
 148       }
 149    }
 150
 151    tri.det = header->det;  /* only the sign matters */
 152    tri.v[0] = v0;
 153    tri.v[1] = v2;
 154    tri.v[2] = v3;
 155    stage->next->tri( stage->next, &tri );
 156
 157    tri.v[0] = v0;
 158    tri.v[1] = v3;
 159    tri.v[2] = v1;
 160    stage->next->tri( stage->next, &tri );
 161 }
 162
 163
 164 /**
 165  * Draw a wide line by drawing a quad, using geometry which will
 166  * fullfill GL's antialiased line requirements.
 167  */
 168 static void wide_line_aa(struct draw_stage *stage,
 169                          struct prim_header *header)
 170 {
 171    const struct wide_stage *wide = wide_stage(stage);
 172    const float half_width = wide->half_line_width;
 173    struct prim_header tri;
 174    struct vertex_header *v[4];
 175    float *pos;
 176    float dx = header->v[1]->data[0][0] - header->v[0]->data[0][0];
 177    float dy = header->v[1]->data[0][1] - header->v[0]->data[0][1];
 178    const float len = (float) sqrt(dx * dx + dy * dy);
 179    uint i;
 180
 181    dx = dx * half_width / len;
 182    dy = dy * half_width / len;
 183
 184    /* allocate/dup new verts */
 185    for (i = 0; i < 4; i++) {
 186       v[i] = dup_vert(stage, header->v[i/2], i);
 187    }
 188
 189    /*
 190     * Quad for line from v0 to v1:
 191     *
 192     *  1                         3
 193     *  +-------------------------+
 194     *  |                         |
 195     *  *v0                     v1*
 196     *  |                         |
 197     *  +-------------------------+
 198     *  0                         2
 199     */
 200
 201    pos = v[0]->data[0];
 202    pos[0] += dy;
 203    pos[1] -= dx;
 204
 205    pos = v[1]->data[0];
 206    pos[0] -= dy;
 207    pos[1] += dx;
 208
 209    pos = v[2]->data[0];
 210    pos[0] += dy;
 211    pos[1] -= dx;
 212
 213    pos = v[3]->data[0];
 214    pos[0] -= dy;
 215    pos[1] += dx;
 216
 217    tri.det = header->det;  /* only the sign matters */
 218
 219    tri.v[0] = v[2];  tri.v[1] = v[1];  tri.v[2] = v[0];
 220    stage->next->tri( stage->next, &tri );
 221
 222    tri.v[0] = v[3];  tri.v[1] = v[1];  tri.v[2] = v[2];
 223    stage->next->tri( stage->next, &tri );
 224
 225 }
 226
 227
 228 /**
 229  * Set the vertex texcoords for sprite mode.
 230  * Coords may be left untouched or set to a right-side-up or upside-down
 231  * orientation.
 232  */
 233 static void set_texcoords(const struct wide_stage *wide,
 234                           struct vertex_header *v, const float tc[4])
 235 {
 236    uint i;
 237    for (i = 0; i < wide->num_texcoords; i++) {
 238       if (wide->texcoord_mode[i] != PIPE_SPRITE_COORD_NONE) {
 239          uint j = wide->texcoord_slot[i];
 240          v->data[j][0] = tc[0];
 241          if (wide->texcoord_mode[i] == PIPE_SPRITE_COORD_LOWER_LEFT)
 242             v->data[j][1] = 1.0f - tc[1];
 243          else
 244             v->data[j][1] = tc[1];
 245          v->data[j][2] = tc[2];
 246          v->data[j][3] = tc[3];
 247       }
 248    }
 249 }
 250
 251
 252 /* If there are lots of sprite points (and why wouldn't there be?) it
 253  * would probably be more sensible to change hardware setup to
 254  * optimize this rather than doing the whole thing in software like
 255  * this.
 256  */
 257 static void wide_point( struct draw_stage *stage,
 258                         struct prim_header *header )
 259 {
 260    const struct wide_stage *wide = wide_stage(stage);
 261    const boolean sprite = (boolean) stage->draw->rasterizer->point_sprite;
 262    float half_size;
 263    float left_adj, right_adj;
 264
 265    struct prim_header tri;
 266
 267    /* four dups of original vertex */
 268    struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
 269    struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
 270    struct vertex_header *v2 = dup_vert(stage, header->v[0], 2);
 271    struct vertex_header *v3 = dup_vert(stage, header->v[0], 3);
 272
 273    float *pos0 = v0->data[0];
 274    float *pos1 = v1->data[0];
 275    float *pos2 = v2->data[0];
 276    float *pos3 = v3->data[0];
 277
 278    /* point size is either per-vertex or fixed size */
 279    if (wide->psize_slot >= 0) {
 280       half_size = 0.5f * header->v[0]->data[wide->psize_slot][0];
 281    }
 282    else {
 283       half_size = wide->half_point_size;
 284    }
 285
 286    left_adj = -half_size + 0.25f;
 287    right_adj = half_size + 0.25f;
 288
 289    pos0[0] += left_adj;
 290    pos0[1] -= half_size;
 291
 292    pos1[0] += left_adj;
 293    pos1[1] += half_size;
 294
 295    pos2[0] += right_adj;
 296    pos2[1] -= half_size;
 297
 298    pos3[0] += right_adj;
 299    pos3[1] += half_size;
 300
 301    if (sprite) {
 302       static const float tex00[4] = { 0, 0, 0, 1 };
 303       static const float tex01[4] = { 0, 1, 0, 1 };
 304       static const float tex11[4] = { 1, 1, 0, 1 };
 305       static const float tex10[4] = { 1, 0, 0, 1 };
 306       set_texcoords( wide, v0, tex00 );
 307       set_texcoords( wide, v1, tex01 );
 308       set_texcoords( wide, v2, tex10 );
 309       set_texcoords( wide, v3, tex11 );
 310    }
 311
 312    tri.det = header->det;  /* only the sign matters */
 313    tri.v[0] = v0;
 314    tri.v[1] = v2;
 315    tri.v[2] = v3;
 316    stage->next->tri( stage->next, &tri );
 317
 318    tri.v[0] = v0;
 319    tri.v[1] = v3;
 320    tri.v[2] = v1;
 321    stage->next->tri( stage->next, &tri );
 322 }
 323
 324
 325 static void wide_first_point( struct draw_stage *stage,
 326                               struct prim_header *header )
 327 {
 328    struct wide_stage *wide = wide_stage(stage);
 329    struct draw_context *draw = stage->draw;
 330
 331    wide->half_point_size = 0.5f * draw->rasterizer->point_size;
 332
 333    if (draw->rasterizer->point_size != 1.0) {
 334       stage->point = wide_point;
 335    }
 336    else {
 337       stage->point = passthrough_point;
 338    }
 339
 340    if (draw->rasterizer->point_sprite) {
 341       /* find vertex shader texcoord outputs */
 342       const struct draw_vertex_shader *vs = draw->vertex_shader;
 343       uint i, j = 0;
 344       for (i = 0; i < vs->state->num_outputs; i++) {
 345          if (vs->state->output_semantic_name[i] == TGSI_SEMANTIC_GENERIC) {
 346             wide->texcoord_slot[j] = i;
 347             wide->texcoord_mode[j] = draw->rasterizer->sprite_coord_mode[j];
 348             j++;
 349          }
 350       }
 351       wide->num_texcoords = j;
 352    }
 353
 354    wide->psize_slot = -1;
 355
 356    if (draw->rasterizer->point_size_per_vertex) {
 357       /* find PSIZ vertex output */
 358       const struct draw_vertex_shader *vs = draw->vertex_shader;
 359       uint i;
 360       for (i = 0; i < vs->state->num_outputs; i++) {
 361          if (vs->state->output_semantic_name[i] == TGSI_SEMANTIC_PSIZE) {
 362             wide->psize_slot = i;
 363             break;
 364          }
 365       }
 366    }
 367
 368    stage->point( stage, header );
 369 }
 370
 371
 372
 373 static void wide_first_line( struct draw_stage *stage,
 374                              struct prim_header *header )
 375 {
 376    struct wide_stage *wide = wide_stage(stage);
 377    struct draw_context *draw = stage->draw;
 378
 379    wide->half_line_width = 0.5f * draw->rasterizer->line_width;
 380
 381    if (draw->rasterizer->line_width != 1.0) {
 382       if (draw->rasterizer->line_smooth)
 383          wide->stage.line = wide_line_aa;
 384       else
 385          wide->stage.line = wide_line;
 386    }
 387    else {
 388       wide->stage.line = passthrough_line;
 389    }
 390
 391    stage->line( stage, header );
 392 }
 393
 394
 395 static void wide_flush( struct draw_stage *stage, unsigned flags )
 396 {
 397    stage->line = wide_first_line;
 398    stage->point = wide_first_point;
 399    stage->next->flush( stage->next, flags );
 400 }
 401
 402
 403 static void wide_reset_stipple_counter( struct draw_stage *stage )
 404 {
 405    stage->next->reset_stipple_counter( stage->next );
 406 }
 407
 408
 409 static void wide_destroy( struct draw_stage *stage )
 410 {
 411    draw_free_temp_verts( stage );
 412    FREE( stage );
 413 }
 414
 415
 416 struct draw_stage *draw_wide_stage( struct draw_context *draw )
 417 {
 418    struct wide_stage *wide = CALLOC_STRUCT(wide_stage);
 419
 420    draw_alloc_temp_verts( &wide->stage, 4 );
 421
 422    wide->stage.draw = draw;
 423    wide->stage.next = NULL;
 424    wide->stage.point = wide_first_point;
 425    wide->stage.line = wide_first_line;
 426    wide->stage.tri = passthrough_tri;
 427    wide->stage.flush = wide_flush;
 428    wide->stage.reset_stipple_counter = wide_reset_stipple_counter;
 429    wide->stage.destroy = wide_destroy;
 430
 431    return &wide->stage;
 432 }