scene.h

   1 #ifndef SCENE_H
   2 #define SCENE_H
   3
   4 #include "common.h"
   5 #include "model.h"
   6 #include "bvh.h"
   7
   8 typedef struct scene scene;
   9
  10 struct scene
  11 {
  12    mdl_vert *arrvertices;
  13    u32 *arrindices;
  14
  15    u32 vertex_count, indice_count,
  16        max_vertices, max_indices;
  17
  18    boxf bbx;
  19    mdl_submesh submesh;
  20 };
  21
  22 /* Initialize a scene description with bounded buffers */
  23 VG_STATIC scene *scene_init( void *lin_alloc, u32 max_verts, u32 max_indices )
  24 {
  25    u32 vertex_length = max_verts   * sizeof(mdl_vert),
  26        index_length  = max_indices * sizeof(u32),
  27        tot_size = sizeof(scene) + vertex_length + index_length;
  28
  29    scene *pscene = vg_linear_alloc( lin_alloc, tot_size );
  30
  31    pscene->arrvertices = (mdl_vert *)(pscene+1);
  32    pscene->arrindices  = (u32 *)( pscene->arrvertices + max_verts );
  33
  34    pscene->vertex_count = 0;
  35    pscene->indice_count = 0;
  36    pscene->max_vertices = max_verts;
  37    pscene->max_indices  = max_indices;
  38
  39    memset( &pscene->submesh, 0, sizeof(mdl_submesh) );
  40
  41    v3_fill( pscene->bbx[0],  999999.9f );
  42    v3_fill( pscene->bbx[1], -999999.9f );
  43
  44    return pscene;
  45 }
  46
  47 /*
  48  * Append a model into the scene with a given transform
  49  */
  50 VG_STATIC void scene_add_submesh( scene *pscene, mdl_context *mdl,
  51                                   mdl_submesh *sm, m4x3f transform )
  52 {
  53    if( pscene->vertex_count + sm->vertex_count > pscene->max_vertices )
  54    {
  55       vg_error( "%u(current) + %u > %u\n", pscene->vertex_count,
  56                                            sm->vertex_count,
  57                                            pscene->max_vertices );
  58
  59       vg_warn( "%p ... %p\n", pscene, sm );
  60       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
  61    }
  62
  63    if( pscene->indice_count + sm->indice_count > pscene->max_indices )
  64    {
  65       vg_error( "%u(current) + %u > %u\n", pscene->indice_count,
  66                                            sm->indice_count,
  67                                            pscene->max_indices );
  68       vg_warn( "%p ... %p\n", pscene, sm );
  69
  70       vg_fatal_exit_loop( "Scene index buffer overflow" );
  71    }
  72
  73    mdl_vert *src_verts =  mdl_submesh_vertices( mdl, sm ),
  74             *dst_verts = &pscene->arrvertices[ pscene->vertex_count ];
  75
  76    u32 *src_indices    =  mdl_submesh_indices( mdl, sm ),
  77        *dst_indices    = &pscene->arrindices[ pscene->indice_count ];
  78
  79    /* Transform and place vertices */
  80    boxf bbxnew;
  81    box_copy( sm->bbx, bbxnew );
  82    m4x3_transform_aabb( transform, bbxnew );
  83    box_concat( pscene->bbx, bbxnew );
  84
  85    m3x3f normal_matrix;
  86    m3x3_copy( transform, normal_matrix );
  87    v3_normalize( normal_matrix[0] );
  88    v3_normalize( normal_matrix[1] );
  89    v3_normalize( normal_matrix[2] );
  90
  91    for( u32 i=0; i<sm->vertex_count; i++ )
  92    {
  93       mdl_vert *pvert = &dst_verts[ i ],
  94                *src = &src_verts[ i ];
  95
  96       m4x3_mulv( transform, src->co, pvert->co );
  97       m3x3_mulv( normal_matrix, src->norm, pvert->norm );
  98
  99       pvert->colour[0] = src->colour[0];
 100       pvert->colour[1] = src->colour[1];
 101       pvert->colour[2] = src->colour[2];
 102       pvert->colour[3] = src->colour[3];
 103       v2_copy( src->uv, pvert->uv );
 104    }
 105
 106    for( u32 i=0; i<sm->indice_count; i++ )
 107    {
 108       dst_indices[i] = src_indices[i] + pscene->vertex_count;
 109    }
 110
 111    pscene->vertex_count += sm->vertex_count;
 112    pscene->indice_count += sm->indice_count;
 113
 114 }
 115
 116 /*
 117  * One by one adders for simplified access (mostly procedural stuff)
 118  */
 119 VG_STATIC void scene_push_tri( scene *pscene, u32 tri[3] )
 120 {
 121    if( pscene->indice_count + 3 > pscene->max_indices )
 122       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 123
 124    u32 *dst = &pscene->arrindices[ pscene->indice_count ];
 125
 126    dst[0] = tri[0];
 127    dst[1] = tri[1];
 128    dst[2] = tri[2];
 129
 130    pscene->indice_count += 3;
 131 }
 132
 133 VG_STATIC void scene_push_vert( scene *pscene, mdl_vert *v )
 134 {
 135    if( pscene->vertex_count + 1 > pscene->max_vertices )
 136       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 137
 138    mdl_vert *dst = &pscene->arrvertices[ pscene->vertex_count ];
 139    *dst = *v;
 140
 141    pscene->vertex_count ++;
 142 }
 143
 144 VG_STATIC void scene_copy_slice( scene *pscene, mdl_submesh *sm )
 145 {
 146    sm->indice_start = pscene->submesh.indice_start;
 147    sm->indice_count = pscene->indice_count - sm->indice_start;
 148
 149    sm->vertex_start = pscene->submesh.vertex_start;
 150    sm->vertex_count = pscene->vertex_count - sm->vertex_start;
 151
 152    pscene->submesh.indice_start = pscene->indice_count;
 153    pscene->submesh.vertex_start = pscene->vertex_count;
 154 }
 155
 156 /* finalization: tightly pack data */
 157 __attribute__((warn_unused_result))
 158 VG_STATIC scene *scene_fix( void *lin_alloc, scene *pscene )
 159 {
 160    return pscene;
 161    u32 vertex_count  = pscene->vertex_count,
 162        indice_count  = pscene->indice_count,
 163        vertex_length = vertex_count * sizeof(mdl_vert),
 164        index_length  = indice_count * sizeof(u32),
 165        tot_size = sizeof(scene) + vertex_length + index_length;
 166
 167    /* copy down index data */
 168    void *dst_indices = pscene->arrvertices + vertex_length;
 169    memmove( dst_indices, pscene->arrindices, index_length );
 170
 171    /* realloc */
 172    pscene = vg_linear_resize( lin_alloc, pscene, tot_size );
 173
 174    pscene->arrvertices = (mdl_vert *)(pscene+1);
 175    pscene->arrindices  = (u32 *)(pscene->arrvertices+vertex_count);
 176    pscene->max_vertices = vertex_count;
 177    pscene->max_indices  = indice_count;
 178
 179    return pscene;
 180 }
 181
 182 #if 0
 183 /* finalization: delete any offline buffers and reduce size */
 184 __attribute__((warn_unused_result))
 185 VG_STATIC scene *scene_free_offline_buffers( void *lin_alloc, scene *pscene )
 186 {
 187    u32 tot_size = sizeof(scene);
 188
 189    scene    *src_scene   = pscene;
 190    mdl_vert *src_verts   = pscene->arrvertices;
 191    u32      *src_indices = pscene->arrindices;
 192
 193    scene *dst_scene = vg_linear_resize( lin_alloc, pscene, tot_size );
 194    memcpy( dst_scene, src_scene, sizeof(scene) );
 195
 196    dst_scene->arrindices = NULL;
 197    dst_scene->arrvertices = NULL;
 198
 199    return dst_scene;
 200 }
 201 #endif
 202
 203 VG_STATIC void scene_upload( scene *pscene, glmesh *mesh )
 204 {
 205    mesh_upload( mesh,
 206                 pscene->arrvertices, pscene->vertex_count,
 207                 pscene->arrindices,  pscene->indice_count );
 208
 209    vg_info( "Scene upload\n" );
 210    vg_info( "   indices:%u\n", pscene->indice_count );
 211    vg_info( "   verts:%u\n", pscene->vertex_count );
 212 }
 213
 214 /*
 215  * BVH implementation
 216  */
 217
 218 VG_STATIC void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 219 {
 220    scene *s = user;
 221    mdl_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 222             *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 223             *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 224
 225   box_addpt( bound, pa->co );
 226   box_addpt( bound, pb->co );
 227   box_addpt( bound, pc->co );
 228 }
 229
 230 VG_STATIC float scene_bh_centroid( void *user, u32 item_index, int axis )
 231 {
 232    scene *s = user;
 233    mdl_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 234             *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 235             *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 236
 237    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 238 }
 239
 240 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 241 {
 242    scene *s = user;
 243
 244    u32 *ti = &s->arrindices[ia*3];
 245    u32 *tj = &s->arrindices[ib*3];
 246
 247    u32 temp[3];
 248    temp[0] = ti[0];
 249    temp[1] = ti[1];
 250    temp[2] = ti[2];
 251
 252    ti[0] = tj[0];
 253    ti[1] = tj[1];
 254    ti[2] = tj[2];
 255
 256    tj[0] = temp[0];
 257    tj[1] = temp[1];
 258    tj[2] = temp[2];
 259 }
 260
 261 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 262 {
 263    scene *s = user;
 264    u32 idx = item_index*3;
 265    mdl_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 266             *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 267             *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 268
 269    vg_line( pa->co, pb->co, 0xff0000ff );
 270    vg_line( pb->co, pc->co, 0xff0000ff );
 271    vg_line( pc->co, pa->co, 0xff0000ff );
 272 }
 273
 274 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 275                             v3f dir, ray_hit *hit )
 276 {
 277    scene *s = user;
 278    v3f positions[3];
 279
 280    u32 *tri = &s->arrindices[ index*3 ];
 281
 282    for( int i=0; i<3; i++ )
 283       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 284
 285    float t;
 286    if(ray_tri( positions, co, dir, &t ))
 287    {
 288       if( t < hit->dist )
 289       {
 290          hit->dist = t;
 291          hit->tri = tri;
 292          return 1;
 293       }
 294    }
 295
 296    return 0;
 297 }
 298
 299 VG_STATIC bh_system bh_system_scene =
 300 {
 301    .expand_bound = scene_bh_expand_bound,
 302    .item_centroid = scene_bh_centroid,
 303    .item_swap = scene_bh_swap,
 304    .item_debug = scene_bh_debug,
 305    .cast_ray = scene_bh_ray
 306 };
 307
 308 /*
 309  * An extra step is added onto the end to calculate the hit normal
 310  */
 311 VG_STATIC int scene_raycast( scene *s, bh_tree *bh,
 312                              v3f co, v3f dir, ray_hit *hit )
 313 {
 314    int count = bh_ray( bh, co, dir, hit );
 315
 316    if( count )
 317    {
 318       v3f v0, v1;
 319
 320       float *pa = s->arrvertices[hit->tri[0]].co,
 321             *pb = s->arrvertices[hit->tri[1]].co,
 322             *pc = s->arrvertices[hit->tri[2]].co;
 323
 324       v3_sub( pa, pb, v0 );
 325       v3_sub( pc, pb, v1 );
 326       v3_cross( v1, v0, hit->normal );
 327       v3_normalize( hit->normal );
 328       v3_muladds( co, dir, hit->dist, hit->pos );
 329    }
 330
 331    return count;
 332 }
 333
 334 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene *s )
 335 {
 336    u32 triangle_count = s->indice_count / 3;
 337    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count );
 338 }
 339
 340 #endif