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