scene.h

   1 #ifndef SCENE_H
   2 #define SCENE_H
   3
   4 #include "vg/vg.h"
   5 #include "model.h"
   6
   7 typedef struct scene scene;
   8 typedef struct bvh_node bvh_node;
   9
  10 struct scene
  11 {
  12    glmesh mesh;
  13
  14    model_vert *verts;
  15    u32 *indices;
  16
  17    struct
  18    {
  19       bvh_node *nodes;
  20       u32 node_count;
  21    }
  22    bvh;
  23
  24    u32 vertex_count,
  25        indice_count,
  26        vertex_cap,
  27        indice_cap;
  28
  29    boxf bbx;
  30
  31    u32 shadower_count,
  32        shadower_cap;
  33
  34    submodel submesh;
  35 };
  36
  37 GLuint tex_dual_noise;
  38
  39 static void scene_init( scene *pscene )
  40 {
  41    pscene->verts = NULL;
  42    pscene->indices = NULL;
  43    pscene->vertex_count = 0;
  44    pscene->indice_count = 0;
  45    pscene->shadower_count = 0;
  46    pscene->shadower_cap = 0;
  47    pscene->submesh.indice_start = 0;
  48    pscene->submesh.indice_count = 0;
  49
  50    v3_fill( pscene->bbx[0],  999999.9f );
  51    v3_fill( pscene->bbx[1], -999999.9f );
  52
  53    static int noise_ready = 0;
  54    if( !noise_ready )
  55    {
  56       noise_ready = 1;
  57
  58       u8 *buf = malloc( 256*256*2 );
  59
  60       for( int i=0; i<256*256; i++ )
  61       {
  62          u8 val = rand()&0xff;
  63          buf[i*2] = val;
  64       }
  65
  66       for( int y=0; y<256; y++ )
  67       {
  68          for( int x=0; x<256; x++ )
  69          {
  70             u8 *pr = &buf[(y*256+x)*2],
  71                *pg = &buf[(((y+17)&0xff)*256+((x+37)&0xff))*2+1];
  72             *pg = *pr;
  73          }
  74       }
  75
  76       /* TODO: This texture should be delted somewhere */
  77       glGenTextures( 1, &tex_dual_noise );
  78       glBindTexture( GL_TEXTURE_2D, tex_dual_noise );
  79       glTexImage2D( GL_TEXTURE_2D, 0, GL_RG, 256, 256, 0, GL_RG,
  80             GL_UNSIGNED_BYTE, buf );
  81
  82       vg_tex2d_linear();
  83       vg_tex2d_repeat();
  84
  85       free( buf );
  86    }
  87 }
  88
  89 static void *buffer_reserve( void *buffer, u32 count, u32 *cap, u32 amount,
  90       size_t emsize )
  91 {
  92    if( count+amount > *cap )
  93    {
  94       *cap = VG_MAX( (*cap)*2, (*cap)+amount );
  95
  96       return realloc( buffer, (*cap) * emsize );
  97    }
  98
  99    return buffer;
 100 }
 101
 102 /*
 103  * Append a model into the scene with a given transform
 104  */
 105 static void scene_add_model( scene *pscene, model *mdl, submodel *submodel,
 106       v3f pos, float yaw, float scale )
 107 {
 108    pscene->verts = buffer_reserve( pscene->verts, pscene->vertex_count,
 109          &pscene->vertex_cap, submodel->vertex_count, sizeof(model_vert) );
 110    pscene->indices = buffer_reserve( pscene->indices, pscene->indice_count,
 111          &pscene->indice_cap, submodel->indice_count, sizeof(u32) );
 112
 113    /* Transform and place vertices */
 114    model_vert *src_verts = submodel_vert_data( mdl, submodel );
 115    u32 *src_indices = submodel_indice_data( mdl, submodel );
 116
 117    m4x3f mtx;
 118    m4x3_identity( mtx );
 119    m4x3_translate( mtx, pos );
 120    m4x3_rotate_y( mtx, yaw );
 121    m4x3_scale( mtx, scale );
 122
 123    boxf bbxnew;
 124    box_copy( submodel->bbx, bbxnew );
 125    m4x3_transform_aabb( mtx, bbxnew );
 126    box_concat( pscene->bbx, bbxnew );
 127
 128    m3x3f rotation;
 129    m4x3_to_3x3( mtx, rotation );
 130
 131    float rand_hue = vg_randf();
 132
 133    for( u32 i=0; i<submodel->vertex_count; i++ )
 134    {
 135       model_vert *pvert = &pscene->verts[ pscene->vertex_count+i ],
 136                  *src = &src_verts[ i ];
 137
 138       m4x3_mulv( mtx, src->co, pvert->co );
 139       m3x3_mulv( rotation, src->norm, pvert->norm );
 140
 141       v4_copy( src->colour, pvert->colour );
 142       v2_copy( src->uv, pvert->uv );
 143
 144       float rel_y = src->co[1] / submodel->bbx[1][1];
 145       pvert->colour[0] = rel_y;
 146       pvert->colour[2] = rand_hue;
 147    }
 148
 149    for( u32 i=0; i<submodel->indice_count; i++ )
 150    {
 151       u32 *pidx = &pscene->indices[ pscene->indice_count+i ];
 152       *pidx = src_indices[i] + pscene->vertex_count;
 153    }
 154
 155    pscene->vertex_count += submodel->vertex_count;
 156    pscene->indice_count += submodel->indice_count;
 157 }
 158
 159 static void scene_add_foliage( scene *pscene, model *mdl, submodel *submodel,
 160       m4x3f transform )
 161 {
 162    pscene->verts = buffer_reserve( pscene->verts, pscene->vertex_count,
 163          &pscene->vertex_cap, submodel->vertex_count, sizeof(model_vert) );
 164    pscene->indices = buffer_reserve( pscene->indices, pscene->indice_count,
 165          &pscene->indice_cap, submodel->indice_count, sizeof(u32) );
 166
 167    /* Transform and place vertices */
 168    model_vert *src_verts = submodel_vert_data( mdl, submodel );
 169    u32 *src_indices = submodel_indice_data( mdl, submodel );
 170
 171    boxf bbxnew;
 172    box_copy( submodel->bbx, bbxnew );
 173    m4x3_transform_aabb( transform, bbxnew );
 174    box_concat( pscene->bbx, bbxnew );
 175
 176    float rand_hue = vg_randf();
 177    for( u32 i=0; i<submodel->vertex_count; i++ )
 178    {
 179       model_vert *pvert = &pscene->verts[ pscene->vertex_count+i ],
 180                  *src = &src_verts[ i ];
 181
 182       m4x3_mulv( transform, src->co, pvert->co );
 183       m3x3_mulv( transform, src->norm, pvert->norm );
 184
 185       v4_copy( src->colour, pvert->colour );
 186       v2_copy( src->uv, pvert->uv );
 187
 188       float rel_y = src->co[1] / submodel->bbx[1][1];
 189       pvert->colour[0] = rel_y;
 190       pvert->colour[2] = rand_hue;
 191    }
 192
 193    for( u32 i=0; i<submodel->indice_count; i++ )
 194    {
 195       u32 *pidx = &pscene->indices[ pscene->indice_count+i ];
 196       *pidx = src_indices[i] + pscene->vertex_count;
 197    }
 198
 199    pscene->vertex_count += submodel->vertex_count;
 200    pscene->indice_count += submodel->indice_count;
 201 }
 202
 203 static void scene_copy_slice( scene *pscene, submodel *sm )
 204 {
 205    sm->indice_start = pscene->submesh.indice_start;
 206    sm->indice_count = pscene->indice_count - sm->indice_start;
 207
 208    sm->vertex_start = pscene->submesh.vertex_start;
 209    sm->vertex_count = pscene->vertex_count - sm->vertex_start;
 210
 211    pscene->submesh.indice_start = pscene->indice_count;
 212    pscene->submesh.vertex_start = pscene->vertex_count;
 213 }
 214
 215 static void scene_upload( scene *pscene )
 216 {
 217    mesh_upload( &pscene->mesh,
 218          pscene->verts, pscene->vertex_count,
 219          pscene->indices, pscene->indice_count );
 220
 221    vg_info( "Scene upload\n" );
 222    vg_info( "   indices:%u\n", pscene->indice_count );
 223    vg_info( "   verts:%u\n", pscene->vertex_count );
 224 }
 225
 226 float scene_tree_sway = 0.1f;
 227
 228 #if 0
 229 static void scene_foliage_shader_use(void)
 230 {
 231    SHADER_USE( shader_debug_vcol );
 232
 233         glUniformMatrix4fv( SHADER_UNIFORM( shader_debug_vcol, "uPv" ),
 234          1, GL_FALSE, (float *)vg_pv );
 235
 236    glUniform1i( SHADER_UNIFORM( shader_debug_vcol, "uMode" ), debugview );
 237    glUniform1i( SHADER_UNIFORM( shader_debug_vcol, "uTexMain" ), 0 );
 238
 239    glUniform1i( SHADER_UNIFORM( shader_debug_vcol, "uTexGradients" ), 1 );
 240    vg_tex2d_bind( &tex_gradients, 1 );
 241
 242    glUniform1i( SHADER_UNIFORM( shader_debug_vcol, "uTexNoise" ), 2 );
 243    glActiveTexture( GL_TEXTURE2 );
 244    glBindTexture( GL_TEXTURE_2D, tex_dual_noise );
 245
 246    glUniform1f( SHADER_UNIFORM( shader_debug_vcol, "uTime" ), vg_time );
 247    glUniform1f( SHADER_UNIFORM( shader_debug_vcol, "uSwayAmt" ),
 248          scene_tree_sway );
 249 }
 250 #endif
 251
 252 static void scene_bind( scene *pscene )
 253 {
 254    mesh_bind( &pscene->mesh );
 255 }
 256
 257 static void scene_draw( scene *pscene )
 258 {
 259    mesh_drawn( 0, pscene->indice_count );
 260 }
 261
 262 static void scene_register(void)
 263 {
 264 }
 265
 266
 267 /* Physics segment */
 268
 269 static int triangle_raycast2d( v3f pA, v3f pB, v3f pC, v3f ray, float *height )
 270 {
 271         v2f v0, v1, v2, vp, vp2;
 272         float d, bca = 0.f, bcb = 0.f, bcc = 0.f;
 273
 274    v0[0] = pB[0] - pA[0];
 275    v0[1] = pB[2] - pA[2];
 276    v1[0] = pC[0] - pA[0];
 277    v1[1] = pC[2] - pA[2];
 278    v2[0] = pB[0] - pC[0];
 279    v2[1] = pB[2] - pC[2];
 280
 281         d = 1.f / (v0[0]*v1[1] - v1[0]*v0[1]);
 282
 283 #if 0
 284         /* Backface culling */
 285         if( v2_cross( v0, v1 ) > 0.f )
 286                 return;
 287 #endif
 288
 289    vp[0] = ray[0] - pA[0];
 290    vp[1] = ray[2] - pA[2];
 291
 292    if( v2_cross( v0, vp ) > 0.f ) return 0;
 293    if( v2_cross( vp, v1 ) > 0.f ) return 0;
 294
 295    vp2[0] = ray[0] - pB[0];
 296    vp2[1] = ray[2] - pB[2];
 297
 298    if( v2_cross( vp2, v2 ) > 0.f ) return 0;
 299
 300    bcb = (vp[0]*v1[1] - v1[0]*vp[1]) * d;
 301    bcc = (v0[0]*vp[1] - vp[0]*v0[1]) * d;
 302    bca = 1.f - bcb - bcc;
 303
 304    *height = pA[1]*bca + pB[1]*bcb + pC[1]*bcc;
 305    return 1;
 306 }
 307
 308 /* Temporary */
 309 static int sample_scene_height( scene *pscene, v3f pos, v3f norm )
 310 {
 311    for( int i=0; i<pscene->indice_count/3; i++ )
 312    {
 313       u32 *tri = &pscene->indices[i*3];
 314
 315       float *pA = pscene->verts[tri[0]].co,
 316             *pB = pscene->verts[tri[1]].co,
 317             *pC = pscene->verts[tri[2]].co;
 318
 319       float height;
 320       if( triangle_raycast2d( pA, pB, pC, pos, &height ))
 321       {
 322          pos[1] = height;
 323
 324          if( norm )
 325          {
 326             v3f v0, v1;
 327             v3_sub( pA, pB, v0 );
 328             v3_sub( pC, pB, v1 );
 329             v3_cross( v1, v0, norm );
 330             v3_normalize( norm );
 331          }
 332
 333          return 1;
 334       }
 335    }
 336    return 0;
 337 }
 338
 339 static void sample_scene_normal( scene *pscene, v3f pos, v3f normal )
 340 {
 341    for( int i=0; i<pscene->indice_count/3; i++ )
 342    {
 343       u32 *tri = &pscene->indices[i*3];
 344
 345       float height;
 346       if( triangle_raycast2d(
 347             pscene->verts[ tri[0] ].co,
 348             pscene->verts[ tri[1] ].co,
 349             pscene->verts[ tri[2] ].co, pos, &height ))
 350       {
 351          v3f v0, v1;
 352
 353          v3_sub( pscene->verts[ tri[1] ].co,
 354                  pscene->verts[ tri[0] ].co,
 355                  v0 );
 356
 357          v3_sub( pscene->verts[ tri[2] ].co,
 358                  pscene->verts[ tri[0] ].co,
 359                  v1 );
 360
 361          v3_cross( v0, v1, normal );
 362          v3_normalize( normal );
 363          return;
 364       }
 365    }
 366
 367    normal[0] = 0.0f;
 368    normal[1] = 1.0f;
 369    normal[2] = 0.0f;
 370 }
 371
 372 struct bvh_node
 373 {
 374    boxf bbx;
 375
 376    /* if il is 0, this is a leaf */
 377    u32 il, count;
 378    union{ u32 ir, start; };
 379 };
 380
 381 static void bvh_update_bounds( scene *s, u32 inode )
 382 {
 383    bvh_node *node = &s->bvh.nodes[ inode ];
 384
 385    box_init_inf( node->bbx );
 386    for( u32 i=0; i<node->count; i++ )
 387    {
 388       u32 idx = node->start+i;
 389       model_vert *pa = &s->verts[ s->indices[idx*3+0] ],
 390                  *pb = &s->verts[ s->indices[idx*3+1] ],
 391                  *pc = &s->verts[ s->indices[idx*3+2] ];
 392
 393      box_addpt( node->bbx, pa->co );
 394      box_addpt( node->bbx, pb->co );
 395      box_addpt( node->bbx, pc->co );
 396    }
 397 }
 398
 399 static void bvh_subdiv( scene *s, u32 inode )
 400 {
 401    bvh_node *node = &s->bvh.nodes[ inode ];
 402
 403    v3f extent;
 404    v3_sub( node->bbx[1], node->bbx[0], extent );
 405
 406    int axis = 0;
 407    if( extent[1] > extent[0] ) axis = 1;
 408    if( extent[2] > extent[axis] ) axis = 2;
 409
 410    float split = node->bbx[0][axis] + extent[axis]*0.5f;
 411
 412    /* To beat: 121,687 / 136,579
 413     *          136,375
 414     */
 415
 416    float avg = 0.0;
 417    for( u32 t=0; t<node->count; t++ )
 418    {
 419       u32 *ti = &s->indices[(node->start+t)*3];
 420       float a = s->verts[ti[0]].co[axis],
 421              b = s->verts[ti[1]].co[axis],
 422              c = s->verts[ti[2]].co[axis];
 423       avg += (a+b+c)/3.0;
 424    }
 425    avg /= (float)node->count;
 426
 427    split = avg;
 428
 429    i32 i = node->start,
 430        j = i + node->count-1;
 431
 432    while( i <= j )
 433    {
 434       u32 *ti = &s->indices[i*3];
 435
 436       float a = s->verts[ti[0]].co[axis],
 437             b = s->verts[ti[1]].co[axis],
 438             c = s->verts[ti[2]].co[axis];
 439
 440       if( ((a+b+c) / 3.0f) < split )
 441          i ++;
 442       else
 443       {
 444          /* Swap triangle indices */
 445          u32 *tj = &s->indices[j*3];
 446          u32 temp[3];
 447          temp[0] = ti[0];
 448          temp[1] = ti[1];
 449          temp[2] = ti[2];
 450
 451          ti[0] = tj[0];
 452          ti[1] = tj[1];
 453          ti[2] = tj[2];
 454
 455          tj[0] = temp[0];
 456          tj[1] = temp[1];
 457          tj[2] = temp[2];
 458
 459          j --;
 460       }
 461    }
 462
 463    u32 left_count = i - node->start;
 464    if( left_count == 0 || left_count == node->count ) return;
 465
 466    u32 il = s->bvh.node_count ++,
 467        ir = s->bvh.node_count ++;
 468
 469    struct bvh_node *lnode = &s->bvh.nodes[il],
 470                    *rnode = &s->bvh.nodes[ir];
 471
 472    lnode->start = node->start;
 473    lnode->count = left_count;
 474    rnode->start = i;
 475    rnode->count = node->count - left_count;
 476
 477    node->il = il;
 478    node->ir = ir;
 479    node->count = 0;
 480
 481    bvh_update_bounds( s, il );
 482    bvh_update_bounds( s, ir );
 483    bvh_subdiv( s, il );
 484    bvh_subdiv( s, ir );
 485 }
 486
 487 static void bvh_create( scene *s )
 488 {
 489    u32 triangle_count = s->indice_count / 3;
 490    s->bvh.nodes = malloc( sizeof(struct bvh_node) * (triangle_count*2-1) );
 491
 492    bvh_node *root = &s->bvh.nodes[0];
 493    s->bvh.node_count = 1;
 494
 495    root->il = 0;
 496    root->ir = 0;
 497    root->count = triangle_count;
 498    root->start = 0;
 499
 500    bvh_update_bounds( s, 0 );
 501    bvh_subdiv( s, 0 );
 502
 503    s->bvh.nodes =
 504       realloc( s->bvh.nodes, sizeof(struct bvh_node) * s->bvh.node_count );
 505
 506    vg_success( "BVH done, size: %u/%u\n", s->bvh.node_count,
 507                                           (triangle_count*2-1) );
 508 }
 509
 510 static void bvh_debug_node( scene *s, u32 inode, v3f pos, u32 colour )
 511 {
 512    struct bvh_node *node = &s->bvh.nodes[ inode ];
 513
 514    if( (pos[0] >= node->bbx[0][0] && pos[0] <= node->bbx[1][0]) &&
 515        (pos[2] >= node->bbx[0][2] && pos[2] <= node->bbx[1][2]) )
 516    {
 517       if( !node->count )
 518       {
 519          vg_line_boxf( node->bbx, colour );
 520
 521          bvh_debug_node( s, node->il, pos, colour );
 522          bvh_debug_node( s, node->ir, pos, colour );
 523       }
 524       else
 525       {
 526          vg_line_boxf( node->bbx, 0xff00ff00 );
 527          for( u32 i=0; i<node->count; i++ )
 528          {
 529             u32 idx = (node->start+i)*3;
 530
 531             model_vert *pa = &s->verts[ s->indices[ idx+0 ] ],
 532                        *pb = &s->verts[ s->indices[ idx+1 ] ],
 533                        *pc = &s->verts[ s->indices[ idx+2 ] ];
 534
 535             vg_line( pa->co, pb->co, 0xff0000ff );
 536             vg_line( pb->co, pc->co, 0xff0000ff );
 537             vg_line( pc->co, pa->co, 0xff0000ff );
 538          }
 539       }
 540    }
 541 }
 542
 543 static void bvh_debug( scene *s, v3f pos )
 544 {
 545    bvh_debug_node( s, 0, pos, 0x4000ffa8 );
 546 }
 547
 548 typedef struct ray_hit ray_hit;
 549 struct ray_hit
 550 {
 551    float dist;
 552    u32 *tri;
 553    v3f pos, normal;
 554 };
 555
 556 int ray_aabb( boxf box, v3f co, v3f dir, float dist )
 557 {
 558    v3f v0, v1;
 559    float tmin, tmax;
 560
 561    v3_sub( box[0], co, v0 );
 562    v3_sub( box[1], co, v1 );
 563    v3_div( v0, dir, v0 );
 564    v3_div( v1, dir, v1 );
 565
 566    tmin = vg_minf( v0[0], v1[0] );
 567    tmax = vg_maxf( v0[0], v1[0] );
 568    tmin = vg_maxf( tmin, vg_minf( v0[1], v1[1] ));
 569    tmax = vg_minf( tmax, vg_maxf( v0[1], v1[1] ));
 570    tmin = vg_maxf( tmin, vg_minf( v0[2], v1[2] ));
 571    tmax = vg_minf( tmax, vg_maxf( v0[2], v1[2] ));
 572
 573    return tmax >= tmin && tmin < dist && tmax > 0;
 574 }
 575
 576 static int bvh_ray_tri( scene *sc, u32 *tri, v3f co, v3f dir, ray_hit *hit )
 577 {
 578    v3f positions[3];
 579    for( int i=0; i<3; i++ )
 580       v3_copy( sc->verts[tri[i]].co, positions[i] );
 581
 582    float t;
 583    if(ray_tri( positions, co, dir, &t ))
 584    {
 585       if( t < hit->dist )
 586       {
 587          hit->dist = t;
 588          hit->tri = tri;
 589          return 1;
 590       }
 591    }
 592
 593    return 0;
 594 }
 595
 596 static int bvh_ray( scene *s, u32 inode, v3f co, v3f dir, ray_hit *hit )
 597 {
 598    bvh_node *node = &s->bvh.nodes[ inode ];
 599
 600    if( !ray_aabb( node->bbx, co, dir, hit->dist ))
 601       return 0;
 602
 603    int count = 0;
 604
 605    if( node->count )
 606    {
 607       for( u32 i=0; i<node->count; i++ )
 608       {
 609          u32 *indices = &s->indices[ (node->start+i)*3 ];
 610          count += bvh_ray_tri( s, indices, co, dir, hit );
 611       }
 612    }
 613    else
 614    {
 615       count += bvh_ray( s, node->il, co, dir, hit );
 616       count += bvh_ray( s, node->ir, co, dir, hit );
 617    }
 618
 619    return count;
 620 }
 621
 622 static int bvh_raycast( scene *s, v3f co, v3f dir, ray_hit *hit )
 623 {
 624    v3f pb;
 625    v3_muladds( co, dir, hit->dist, pb );
 626
 627    int count = bvh_ray( s, 0, co, dir, hit );
 628
 629    if( count )
 630    {
 631       //vg_line( co, pb, 0xff00ffff );
 632
 633       v3f v0, v1;
 634
 635       float *pa = s->verts[hit->tri[0]].co,
 636             *pb = s->verts[hit->tri[1]].co,
 637             *pc = s->verts[hit->tri[2]].co;
 638
 639       v3_sub( pa, pb, v0 );
 640       v3_sub( pc, pb, v1 );
 641       v3_cross( v1, v0, hit->normal );
 642       v3_normalize( hit->normal );
 643       v3_muladds( co, dir, hit->dist, hit->pos );
 644    }
 645    else
 646    {
 647       //vg_line( co, pb, 0xff0000ff );
 648    }
 649
 650    return count;
 651 }
 652
 653 static int bvh_select_triangles( scene *s, boxf box, u32 *triangles, int len )
 654 {
 655    /* TODO: use this stack system on the raycast function */
 656    int count = 0;
 657    u32 stack[100];
 658    u32 depth = 2;
 659
 660    stack[0] = 0;
 661    stack[1] = s->bvh.nodes[0].il;
 662    stack[2] = s->bvh.nodes[0].ir;
 663
 664    while(depth)
 665    {
 666       bvh_node *inode = &s->bvh.nodes[ stack[depth] ];
 667       if( box_overlap( inode->bbx, box ) )
 668       {
 669          if( inode->count )
 670          {
 671             if( count + inode->count >= len )
 672             {
 673                vg_error( "Maximum buffer reached!\n" );
 674                return count;
 675             }
 676
 677             for( u32 i=0; i<inode->count; i++ )
 678                triangles[ count ++ ] = (inode->start+i)*3;
 679
 680             depth --;
 681          }
 682          else
 683          {
 684             if( depth+1 >= vg_list_size(stack) )
 685             {
 686                vg_error( "Maximum stack reached!\n" );
 687                return count;
 688             }
 689
 690             stack[depth] = inode->il;
 691             stack[depth+1] = inode->ir;
 692             depth ++;
 693          }
 694       }
 695       else
 696       {
 697          depth --;
 698       }
 699    }
 700
 701    return count;
 702 }
 703
 704 static int bvh_scene_sample_node_h( scene *s, u32 inode, v3f pos, v3f norm )
 705 {
 706    bvh_node *node = &s->bvh.nodes[ inode ];
 707
 708    if( (pos[0] >= node->bbx[0][0] && pos[0] <= node->bbx[1][0]) &&
 709        (pos[2] >= node->bbx[0][2] && pos[2] <= node->bbx[1][2]) )
 710    {
 711       if( !node->count )
 712       {
 713          if( bvh_scene_sample_node_h( s, node->il, pos, norm )) return 1;
 714          if( bvh_scene_sample_node_h( s, node->ir, pos, norm )) return 1;
 715       }
 716       else
 717       {
 718          for( u32 i=0; i<node->count; i++ )
 719          {
 720             u32 idx = (node->start+i)*3;
 721             model_vert *pa = &s->verts[ s->indices[ idx+0 ] ],
 722                        *pb = &s->verts[ s->indices[ idx+1 ] ],
 723                        *pc = &s->verts[ s->indices[ idx+2 ] ];
 724
 725             float height;
 726             if( triangle_raycast2d( pa->co, pb->co, pc->co, pos, &height ))
 727             {
 728                pos[1] = height;
 729
 730                if( norm )
 731                {
 732                   v3f v0, v1;
 733                   v3_sub( pa->co, pb->co, v0 );
 734                   v3_sub( pc->co, pb->co, v1 );
 735                   v3_cross( v1, v0, norm );
 736                   v3_normalize( norm );
 737                }
 738
 739                return 1;
 740             }
 741          }
 742       }
 743    }
 744
 745    return 0;
 746 }
 747
 748 static int bvh_scene_sample_h( scene *s, v3f pos, v3f norm)
 749 {
 750    return bvh_scene_sample_node_h( s, 0, pos, norm );
 751 }
 752
 753 static int bvh_scene_sample( scene *s, v3f pos, ray_hit *hit )
 754 {
 755    hit->dist = INFINITY;
 756
 757    v3f ray_pos;
 758    v3_add( pos, (v3f){0.0f,4.0f,0.0f}, ray_pos );
 759
 760    if( bvh_raycast( s, ray_pos, (v3f){0.0f,-1.0f,0.0f}, hit ))
 761    {
 762       pos[1] = hit->pos[1];
 763       return 1;
 764    }
 765
 766    return 0;
 767 }
 768
 769 #endif