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 typedef struct scene_vert scene_vert;
  10
  11 #pragma pack(push,1)
  12
  13 /* 32 byte vertexs, we don't care about the normals too much,
  14  *    maybe possible to bring down uv to i16s too */
  15 struct scene_vert
  16 {
  17    v3f co;        /* 3*32 */
  18    v2f uv;        /* 2*32 */
  19    i8  norm[4];   /* 4*8 */
  20    u16 unused[4];
  21 };
  22
  23 #pragma pack(pop)
  24
  25 struct scene
  26 {
  27    scene_vert *arrvertices;
  28
  29    u32 *arrindices;
  30
  31    u32 vertex_count, indice_count,
  32        max_vertices, max_indices;
  33
  34    boxf bbx;
  35    mdl_submesh submesh;
  36 };
  37
  38 /* Initialize a scene description with bounded buffers */
  39 VG_STATIC scene *scene_init( void *lin_alloc, u32 max_verts, u32 max_indices )
  40 {
  41    u32 vertex_length = max_verts   * sizeof(scene_vert),
  42        index_length  = max_indices * sizeof(u32),
  43        tot_size = sizeof(scene) + vertex_length + index_length;
  44
  45    scene *pscene = vg_linear_alloc( lin_alloc, tot_size );
  46
  47    pscene->arrvertices = (scene_vert *)(pscene+1);
  48    pscene->arrindices  = (u32 *)( pscene->arrvertices + max_verts );
  49
  50    pscene->vertex_count = 0;
  51    pscene->indice_count = 0;
  52    pscene->max_vertices = max_verts;
  53    pscene->max_indices  = max_indices;
  54
  55    memset( &pscene->submesh, 0, sizeof(mdl_submesh) );
  56
  57    v3_fill( pscene->bbx[0],  999999.9f );
  58    v3_fill( pscene->bbx[1], -999999.9f );
  59
  60    return pscene;
  61 }
  62
  63 VG_STATIC void scene_vert_pack_norm( scene_vert *vert, v3f norm )
  64 {
  65    v3f n;
  66    v3_muls( norm, 127.0f, n );
  67    v3_minv( n, (v3f){  127.0f,  127.0f,  127.0f }, n );
  68    v3_maxv( n, (v3f){ -127.0f, -127.0f, -127.0f }, n );
  69    vert->norm[0] = n[0];
  70    vert->norm[1] = n[1];
  71    vert->norm[2] = n[2];
  72    vert->norm[3] = 0;  /* free byte :D */
  73 }
  74
  75 /*
  76  * Append a model into the scene with a given transform
  77  */
  78 VG_STATIC void scene_add_mdl_submesh( scene *pscene, mdl_context *mdl,
  79                                       mdl_submesh *sm, m4x3f transform )
  80 {
  81    if( pscene->vertex_count + sm->vertex_count > pscene->max_vertices )
  82    {
  83       vg_error( "%u(current) + %u > %u\n", pscene->vertex_count,
  84                                            sm->vertex_count,
  85                                            pscene->max_vertices );
  86
  87       vg_warn( "%p ... %p\n", pscene, sm );
  88       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
  89    }
  90
  91    if( pscene->indice_count + sm->indice_count > pscene->max_indices )
  92    {
  93       vg_error( "%u(current) + %u > %u\n", pscene->indice_count,
  94                                            sm->indice_count,
  95                                            pscene->max_indices );
  96       vg_warn( "%p ... %p\n", pscene, sm );
  97
  98       vg_fatal_exit_loop( "Scene index buffer overflow" );
  99    }
 100
 101    mdl_vert   *src_verts =  mdl_submesh_vertices( mdl, sm );
 102    scene_vert *dst_verts = &pscene->arrvertices[ pscene->vertex_count ];
 103
 104    u32 *src_indices    =  mdl_submesh_indices( mdl, sm ),
 105        *dst_indices    = &pscene->arrindices[ pscene->indice_count ];
 106
 107    /* Transform and place vertices */
 108    boxf bbxnew;
 109    box_copy( sm->bbx, bbxnew );
 110    m4x3_transform_aabb( transform, bbxnew );
 111    box_concat( pscene->bbx, bbxnew );
 112
 113    m3x3f normal_matrix;
 114    m3x3_copy( transform, normal_matrix );
 115    v3_normalize( normal_matrix[0] );
 116    v3_normalize( normal_matrix[1] );
 117    v3_normalize( normal_matrix[2] );
 118
 119    for( u32 i=0; i<sm->vertex_count; i++ )
 120    {
 121       mdl_vert   *src   = &src_verts[ i ];
 122       scene_vert *pvert = &dst_verts[ i ];
 123
 124       m4x3_mulv( transform, src->co, pvert->co );
 125
 126       v3f normal;
 127       m3x3_mulv( normal_matrix, src->norm, normal );
 128       scene_vert_pack_norm( pvert, normal );
 129
 130       v2_copy( src->uv, pvert->uv );
 131    }
 132
 133    for( u32 i=0; i<sm->indice_count; i++ )
 134       dst_indices[i] = src_indices[i] + pscene->vertex_count;
 135
 136    pscene->vertex_count += sm->vertex_count;
 137    pscene->indice_count += sm->indice_count;
 138 }
 139
 140 /*
 141  * One by one adders for simplified access (mostly procedural stuff)
 142  */
 143 VG_STATIC void scene_push_tri( scene *pscene, u32 tri[3] )
 144 {
 145    if( pscene->indice_count + 3 > pscene->max_indices )
 146       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 147
 148    u32 *dst = &pscene->arrindices[ pscene->indice_count ];
 149
 150    dst[0] = tri[0];
 151    dst[1] = tri[1];
 152    dst[2] = tri[2];
 153
 154    pscene->indice_count += 3;
 155 }
 156
 157 VG_STATIC void scene_push_vert( scene *pscene, scene_vert *v )
 158 {
 159    if( pscene->vertex_count + 1 > pscene->max_vertices )
 160       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 161
 162    scene_vert *dst = &pscene->arrvertices[ pscene->vertex_count ];
 163    *dst = *v;
 164
 165    pscene->vertex_count ++;
 166 }
 167
 168 VG_STATIC void scene_copy_slice( scene *pscene, mdl_submesh *sm )
 169 {
 170    sm->indice_start = pscene->submesh.indice_start;
 171    sm->indice_count = pscene->indice_count - sm->indice_start;
 172
 173    sm->vertex_start = pscene->submesh.vertex_start;
 174    sm->vertex_count = pscene->vertex_count - sm->vertex_start;
 175
 176    pscene->submesh.indice_start = pscene->indice_count;
 177    pscene->submesh.vertex_start = pscene->vertex_count;
 178 }
 179
 180 /* finalization: tightly pack data */
 181 __attribute__((warn_unused_result))
 182 VG_STATIC scene *scene_fix( void *lin_alloc, scene *pscene )
 183 {
 184    /* FIXME: Why is this disabled? */
 185
 186    u32 vertex_count  = pscene->vertex_count,
 187        indice_count  = pscene->indice_count,
 188        vertex_length = vertex_count * sizeof(scene_vert),
 189        index_length  = indice_count * sizeof(u32),
 190        tot_size      = sizeof(scene) + vertex_length + index_length;
 191
 192    /* copy down index data */
 193    void *dst_indices = pscene->arrvertices + vertex_count;
 194    memmove( dst_indices, pscene->arrindices, index_length );
 195
 196    /* realloc */
 197    pscene = vg_linear_resize( lin_alloc, pscene, tot_size );
 198
 199    pscene->arrvertices = (scene_vert *)(pscene+1);
 200    pscene->arrindices  = (u32 *)(pscene->arrvertices+vertex_count);
 201    pscene->max_vertices = vertex_count;
 202    pscene->max_indices  = indice_count;
 203
 204    return pscene;
 205 }
 206
 207 #if 0
 208 /* finalization: delete any offline buffers and reduce size */
 209 __attribute__((warn_unused_result))
 210 VG_STATIC scene *scene_free_offline_buffers( void *lin_alloc, scene *pscene )
 211 {
 212    u32 tot_size = sizeof(scene);
 213
 214    scene    *src_scene   = pscene;
 215    mdl_vert *src_verts   = pscene->arrvertices;
 216    u32      *src_indices = pscene->arrindices;
 217
 218    scene *dst_scene = vg_linear_resize( lin_alloc, pscene, tot_size );
 219    memcpy( dst_scene, src_scene, sizeof(scene) );
 220
 221    dst_scene->arrindices = NULL;
 222    dst_scene->arrvertices = NULL;
 223
 224    return dst_scene;
 225 }
 226 #endif
 227
 228 VG_STATIC void scene_upload( scene *pscene, glmesh *mesh )
 229 {
 230    //assert( mesh->loaded == 0 );
 231
 232    glGenVertexArrays( 1, &mesh->vao );
 233    glGenBuffers( 1, &mesh->vbo );
 234    glGenBuffers( 1, &mesh->ebo );
 235    glBindVertexArray( mesh->vao );
 236
 237    size_t stride = sizeof(scene_vert);
 238
 239    glBindBuffer( GL_ARRAY_BUFFER, mesh->vbo );
 240    glBufferData( GL_ARRAY_BUFFER, pscene->vertex_count*stride,
 241                  pscene->arrvertices, GL_STATIC_DRAW );
 242
 243    glBindVertexArray( mesh->vao );
 244    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, mesh->ebo );
 245    glBufferData( GL_ELEMENT_ARRAY_BUFFER, pscene->indice_count*sizeof(u32),
 246                  pscene->arrindices, GL_STATIC_DRAW );
 247
 248    /* 0: coordinates */
 249    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0 );
 250    glEnableVertexAttribArray( 0 );
 251
 252    /* 1: normal */
 253    glVertexAttribPointer( 1, 3, GL_BYTE, GL_TRUE,
 254          stride, (void *)offsetof(scene_vert, norm) );
 255    glEnableVertexAttribArray( 1 );
 256
 257    /* 2: uv */
 258    glVertexAttribPointer( 2, 2, GL_FLOAT, GL_FALSE,
 259          stride, (void *)offsetof(scene_vert, uv) );
 260    glEnableVertexAttribArray( 2 );
 261
 262 #if 0
 263    /* 3: light cluster */
 264    glVertexAttribIPointer( 3, 4, GL_UNSIGNED_SHORT,
 265          stride, (void *)offsetof(scene_vert, lights) );
 266    glEnableVertexAttribArray( 3 );
 267 #endif
 268
 269    VG_CHECK_GL_ERR();
 270
 271    mesh->indice_count = pscene->indice_count;
 272    mesh->loaded = 1;
 273
 274    vg_info( "Scene upload ( XYZ_f32 UV_f32 XYZW_i8 )[ u32 ]\n" );
 275    vg_info( "   indices:%u\n", pscene->indice_count );
 276    vg_info( "   verts:%u\n",   pscene->vertex_count );
 277 }
 278
 279 /*
 280  * BVH implementation
 281  */
 282
 283 VG_STATIC void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 284 {
 285    scene *s = user;
 286    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 287               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 288               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 289
 290   box_addpt( bound, pa->co );
 291   box_addpt( bound, pb->co );
 292   box_addpt( bound, pc->co );
 293 }
 294
 295 VG_STATIC float scene_bh_centroid( void *user, u32 item_index, int axis )
 296 {
 297    scene *s = user;
 298    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 299               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 300               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 301
 302    #if 0
 303
 304    float min, max;
 305
 306    min = vg_minf( pa->co[axis], pb->co[axis] );
 307    max = vg_maxf( pa->co[axis], pb->co[axis] );
 308    min = vg_minf( min, pc->co[axis] );
 309    max = vg_maxf( max, pc->co[axis] );
 310
 311    return (min+max) * 0.5f;
 312
 313    #else
 314    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 315    #endif
 316 }
 317
 318 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 319 {
 320    scene *s = user;
 321
 322    u32 *ti = &s->arrindices[ia*3];
 323    u32 *tj = &s->arrindices[ib*3];
 324
 325    u32 temp[3];
 326    temp[0] = ti[0];
 327    temp[1] = ti[1];
 328    temp[2] = ti[2];
 329
 330    ti[0] = tj[0];
 331    ti[1] = tj[1];
 332    ti[2] = tj[2];
 333
 334    tj[0] = temp[0];
 335    tj[1] = temp[1];
 336    tj[2] = temp[2];
 337 }
 338
 339 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 340 {
 341    scene *s = user;
 342    u32 idx = item_index*3;
 343    scene_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 344               *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 345               *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 346
 347    vg_line( pa->co, pb->co, 0xff0000ff );
 348    vg_line( pb->co, pc->co, 0xff0000ff );
 349    vg_line( pc->co, pa->co, 0xff0000ff );
 350 }
 351
 352 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 353                             v3f dir, ray_hit *hit )
 354 {
 355    scene *s = user;
 356    v3f positions[3];
 357
 358    u32 *tri = &s->arrindices[ index*3 ];
 359
 360    for( int i=0; i<3; i++ )
 361       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 362
 363    float t;
 364    if(ray_tri( positions, co, dir, &t ))
 365    {
 366       if( t < hit->dist )
 367       {
 368          hit->dist = t;
 369          hit->tri = tri;
 370          return 1;
 371       }
 372    }
 373
 374    return 0;
 375 }
 376
 377 VG_STATIC void scene_bh_closest( void *user, u32 index, v3f point, v3f closest )
 378 {
 379    scene *s = user;
 380
 381    v3f positions[3];
 382    u32 *tri = &s->arrindices[ index*3 ];
 383    for( int i=0; i<3; i++ )
 384       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 385
 386    closest_on_triangle_1( point, positions, closest );
 387 }
 388
 389 VG_STATIC bh_system bh_system_scene =
 390 {
 391    .expand_bound = scene_bh_expand_bound,
 392    .item_centroid = scene_bh_centroid,
 393    .item_closest = scene_bh_closest,
 394    .item_swap = scene_bh_swap,
 395    .item_debug = scene_bh_debug,
 396    .cast_ray = scene_bh_ray
 397 };
 398
 399 /*
 400  * An extra step is added onto the end to calculate the hit normal
 401  */
 402 VG_STATIC int scene_raycast( scene *s, bh_tree *bh,
 403                              v3f co, v3f dir, ray_hit *hit )
 404 {
 405    int count = bh_ray( bh, co, dir, hit );
 406
 407    if( count )
 408    {
 409       v3f v0, v1;
 410
 411       float *pa = s->arrvertices[hit->tri[0]].co,
 412             *pb = s->arrvertices[hit->tri[1]].co,
 413             *pc = s->arrvertices[hit->tri[2]].co;
 414
 415       v3_sub( pa, pb, v0 );
 416       v3_sub( pc, pb, v1 );
 417       v3_cross( v1, v0, hit->normal );
 418       v3_normalize( hit->normal );
 419       v3_muladds( co, dir, hit->dist, hit->pos );
 420    }
 421
 422    return count;
 423 }
 424
 425 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene *s )
 426 {
 427    u32 triangle_count = s->indice_count / 3;
 428    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count, 2 );
 429 }
 430
 431 #endif