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    pscene->submesh.indice_start = 0;
  40    pscene->submesh.indice_count = 0;
  41
  42    v3_fill( pscene->bbx[0],  999999.9f );
  43    v3_fill( pscene->bbx[1], -999999.9f );
  44
  45    return pscene;
  46 }
  47
  48 /*
  49  * Append a model into the scene with a given transform
  50  */
  51 VG_STATIC void scene_add_submesh( scene *pscene, mdl_context *mdl,
  52                                   mdl_submesh *sm, m4x3f transform )
  53 {
  54    if( pscene->vertex_count + sm->vertex_count > pscene->max_vertices )
  55    {
  56       vg_error( "%u(current) + %u > %u\n", pscene->vertex_count,
  57                                            sm->vertex_count,
  58                                            pscene->max_vertices );
  59
  60       vg_warn( "%p ... %p\n", pscene, sm );
  61       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
  62    }
  63
  64    if( pscene->indice_count + sm->indice_count > pscene->max_indices )
  65    {
  66       vg_error( "%u(current) + %u > %u\n", pscene->indice_count,
  67                                            sm->indice_count,
  68                                            pscene->max_indices );
  69       vg_warn( "%p ... %p\n", pscene, sm );
  70
  71       vg_fatal_exit_loop( "Scene index buffer overflow" );
  72    }
  73
  74    mdl_vert *src_verts =  mdl_submesh_vertices( mdl, sm ),
  75             *dst_verts = &pscene->arrvertices[ pscene->vertex_count ];
  76
  77    u32 *src_indices    =  mdl_submesh_indices( mdl, sm ),
  78        *dst_indices    = &pscene->arrindices[ pscene->indice_count ];
  79
  80    /* Transform and place vertices */
  81    boxf bbxnew;
  82    box_copy( sm->bbx, bbxnew );
  83    m4x3_transform_aabb( transform, bbxnew );
  84    box_concat( pscene->bbx, bbxnew );
  85
  86    m3x3f normal_matrix;
  87    m3x3_copy( transform, normal_matrix );
  88    v3_normalize( normal_matrix[0] );
  89    v3_normalize( normal_matrix[1] );
  90    v3_normalize( normal_matrix[2] );
  91
  92    for( u32 i=0; i<sm->vertex_count; i++ )
  93    {
  94       mdl_vert *pvert = &dst_verts[ i ],
  95                *src = &src_verts[ i ];
  96
  97       m4x3_mulv( transform, src->co, pvert->co );
  98       m3x3_mulv( normal_matrix, src->norm, pvert->norm );
  99
 100       pvert->colour[0] = src->colour[0];
 101       pvert->colour[1] = src->colour[1];
 102       pvert->colour[2] = src->colour[2];
 103       pvert->colour[3] = src->colour[3];
 104       v2_copy( src->uv, pvert->uv );
 105    }
 106
 107    for( u32 i=0; i<sm->indice_count; i++ )
 108    {
 109       dst_indices[i] = src_indices[i] + pscene->vertex_count;
 110    }
 111
 112    pscene->vertex_count += sm->vertex_count;
 113    pscene->indice_count += sm->indice_count;
 114
 115 }
 116
 117 /*
 118  * One by one adders for simplified access (mostly procedural stuff)
 119  */
 120 VG_STATIC void scene_push_tri( scene *pscene, u32 tri[3] )
 121 {
 122    if( pscene->indice_count + 3 > pscene->max_indices )
 123       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 124
 125    u32 *dst = &pscene->arrindices[ pscene->indice_count ];
 126
 127    dst[0] = tri[0];
 128    dst[1] = tri[1];
 129    dst[2] = tri[2];
 130
 131    pscene->indice_count += 3;
 132 }
 133
 134 VG_STATIC void scene_push_vert( scene *pscene, mdl_vert *v )
 135 {
 136    if( pscene->vertex_count + 1 > pscene->max_vertices )
 137       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 138
 139    mdl_vert *dst = &pscene->arrvertices[ pscene->vertex_count ];
 140    *dst = *v;
 141
 142    pscene->vertex_count ++;
 143 }
 144
 145 VG_STATIC void scene_copy_slice( scene *pscene, mdl_submesh *sm )
 146 {
 147    sm->indice_start = pscene->submesh.indice_start;
 148    sm->indice_count = pscene->indice_count - sm->indice_start;
 149
 150    sm->vertex_start = pscene->submesh.vertex_start;
 151    sm->vertex_count = pscene->vertex_count - sm->vertex_start;
 152
 153    pscene->submesh.indice_start = pscene->indice_count;
 154    pscene->submesh.vertex_start = pscene->vertex_count;
 155 }
 156
 157 /* finalization: tightly pack data */
 158 __attribute__((warn_unused_result))
 159 VG_STATIC scene *scene_fix( void *lin_alloc, scene *pscene )
 160 {
 161    u32 vertex_length = pscene->vertex_count * sizeof(mdl_vert),
 162        index_length  = pscene->indice_count * sizeof(u32),
 163        tot_size = sizeof(scene) + vertex_length + index_length;
 164
 165    scene    *src_scene   = pscene;
 166    mdl_vert *src_verts   = pscene->arrvertices;
 167    u32      *src_indices = pscene->arrindices;
 168
 169    scene *dst_scene = vg_linear_resize( lin_alloc, pscene, tot_size );
 170    memcpy( dst_scene, src_scene, sizeof(scene) );
 171
 172    void *dst_verts   = dst_scene+1,
 173         *dst_indices = dst_verts + vertex_length;
 174
 175    memcpy( dst_verts, src_verts, vertex_length );
 176    memcpy( dst_indices, src_indices, index_length );
 177
 178    dst_scene->arrvertices = dst_verts;
 179    dst_scene->arrindices  = dst_indices;
 180    dst_scene->max_vertices = pscene->vertex_count;
 181    dst_scene->max_indices  = pscene->indice_count;
 182
 183    return dst_scene;
 184 }
 185
 186 #if 0
 187 /* finalization: delete any offline buffers and reduce size */
 188 __attribute__((warn_unused_result))
 189 VG_STATIC scene *scene_free_offline_buffers( void *lin_alloc, scene *pscene )
 190 {
 191    u32 tot_size = sizeof(scene);
 192
 193    scene    *src_scene   = pscene;
 194    mdl_vert *src_verts   = pscene->arrvertices;
 195    u32      *src_indices = pscene->arrindices;
 196
 197    scene *dst_scene = vg_linear_resize( lin_alloc, pscene, tot_size );
 198    memcpy( dst_scene, src_scene, sizeof(scene) );
 199
 200    dst_scene->arrindices = NULL;
 201    dst_scene->arrvertices = NULL;
 202
 203    return dst_scene;
 204 }
 205 #endif
 206
 207 VG_STATIC void scene_upload( scene *pscene, glmesh *mesh )
 208 {
 209    mesh_upload( mesh,
 210                 pscene->arrvertices, pscene->vertex_count,
 211                 pscene->arrindices,  pscene->indice_count );
 212
 213    vg_info( "Scene upload\n" );
 214    vg_info( "   indices:%u\n", pscene->indice_count );
 215    vg_info( "   verts:%u\n", pscene->vertex_count );
 216 }
 217
 218 /*
 219  * BVH implementation
 220  */
 221
 222 VG_STATIC void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 223 {
 224    scene *s = user;
 225    mdl_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 226             *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 227             *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 228
 229   box_addpt( bound, pa->co );
 230   box_addpt( bound, pb->co );
 231   box_addpt( bound, pc->co );
 232 }
 233
 234 VG_STATIC float scene_bh_centroid( void *user, u32 item_index, int axis )
 235 {
 236    scene *s = user;
 237    mdl_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 238             *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 239             *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 240
 241    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 242 }
 243
 244 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 245 {
 246    scene *s = user;
 247
 248    u32 *ti = &s->arrindices[ia*3];
 249    u32 *tj = &s->arrindices[ib*3];
 250
 251    u32 temp[3];
 252    temp[0] = ti[0];
 253    temp[1] = ti[1];
 254    temp[2] = ti[2];
 255
 256    ti[0] = tj[0];
 257    ti[1] = tj[1];
 258    ti[2] = tj[2];
 259
 260    tj[0] = temp[0];
 261    tj[1] = temp[1];
 262    tj[2] = temp[2];
 263 }
 264
 265 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 266 {
 267    scene *s = user;
 268    u32 idx = item_index*3;
 269    mdl_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 270             *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 271             *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 272
 273    vg_line( pa->co, pb->co, 0xff0000ff );
 274    vg_line( pb->co, pc->co, 0xff0000ff );
 275    vg_line( pc->co, pa->co, 0xff0000ff );
 276 }
 277
 278 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 279                             v3f dir, ray_hit *hit )
 280 {
 281    scene *s = user;
 282    v3f positions[3];
 283
 284    u32 *tri = &s->arrindices[ index*3 ];
 285
 286    for( int i=0; i<3; i++ )
 287       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 288
 289    float t;
 290    if(ray_tri( positions, co, dir, &t ))
 291    {
 292       if( t < hit->dist )
 293       {
 294          hit->dist = t;
 295          hit->tri = tri;
 296          return 1;
 297       }
 298    }
 299
 300    return 0;
 301 }
 302
 303 VG_STATIC bh_system bh_system_scene =
 304 {
 305    .expand_bound = scene_bh_expand_bound,
 306    .item_centroid = scene_bh_centroid,
 307    .item_swap = scene_bh_swap,
 308    .item_debug = scene_bh_debug,
 309    .cast_ray = scene_bh_ray
 310 };
 311
 312 /*
 313  * An extra step is added onto the end to calculate the hit normal
 314  */
 315 VG_STATIC int scene_raycast( scene *s, bh_tree *bh,
 316                              v3f co, v3f dir, ray_hit *hit )
 317 {
 318    int count = bh_ray( bh, co, dir, hit );
 319
 320    if( count )
 321    {
 322       v3f v0, v1;
 323
 324       float *pa = s->arrvertices[hit->tri[0]].co,
 325             *pb = s->arrvertices[hit->tri[1]].co,
 326             *pc = s->arrvertices[hit->tri[2]].co;
 327
 328       v3_sub( pa, pb, v0 );
 329       v3_sub( pc, pb, v1 );
 330       v3_cross( v1, v0, hit->normal );
 331       v3_normalize( hit->normal );
 332       v3_muladds( co, dir, hit->dist, hit->pos );
 333    }
 334
 335    return count;
 336 }
 337
 338 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene *s )
 339 {
 340    u32 triangle_count = s->indice_count / 3;
 341    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count );
 342 }
 343
 344 #endif