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 /* 24 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 };
  21
  22 #pragma pack(pop)
  23
  24 struct scene
  25 {
  26    scene_vert *arrvertices;
  27
  28    u32 *arrindices;
  29
  30    u32 vertex_count, indice_count,
  31        max_vertices, max_indices;
  32
  33    boxf bbx;
  34    mdl_submesh submesh;
  35 };
  36
  37 /* Initialize a scene description with bounded buffers */
  38 VG_STATIC scene *scene_init( void *lin_alloc, u32 max_verts, u32 max_indices )
  39 {
  40    u32 vertex_length = max_verts   * sizeof(scene_vert),
  41        index_length  = max_indices * sizeof(u32),
  42        tot_size = sizeof(scene) + vertex_length + index_length;
  43
  44    scene *pscene = vg_linear_alloc( lin_alloc, tot_size );
  45
  46    pscene->arrvertices = (scene_vert *)(pscene+1);
  47    pscene->arrindices  = (u32 *)( pscene->arrvertices + max_verts );
  48
  49    pscene->vertex_count = 0;
  50    pscene->indice_count = 0;
  51    pscene->max_vertices = max_verts;
  52    pscene->max_indices  = max_indices;
  53
  54    memset( &pscene->submesh, 0, sizeof(mdl_submesh) );
  55
  56    v3_fill( pscene->bbx[0],  999999.9f );
  57    v3_fill( pscene->bbx[1], -999999.9f );
  58
  59    return pscene;
  60 }
  61
  62 VG_STATIC void scene_vert_pack_norm( scene_vert *vert, v3f norm )
  63 {
  64    v3f n;
  65    v3_muls( norm, 127.0f, n );
  66    v3_minv( n, (v3f){  127.0f,  127.0f,  127.0f }, n );
  67    v3_maxv( n, (v3f){ -127.0f, -127.0f, -127.0f }, n );
  68    vert->norm[0] = n[0];
  69    vert->norm[1] = n[1];
  70    vert->norm[2] = n[2];
  71    vert->norm[3] = 0;  /* free byte :D */
  72 }
  73
  74 /*
  75  * Append a model into the scene with a given transform
  76  */
  77 VG_STATIC void scene_add_mdl_submesh( scene *pscene, mdl_context *mdl,
  78                                       mdl_submesh *sm, m4x3f transform )
  79 {
  80    if( pscene->vertex_count + sm->vertex_count > pscene->max_vertices )
  81    {
  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    {
  92       vg_error( "%u(current) + %u > %u\n", pscene->indice_count,
  93                                            sm->indice_count,
  94                                            pscene->max_indices );
  95       vg_warn( "%p ... %p\n", pscene, sm );
  96
  97       vg_fatal_exit_loop( "Scene index buffer overflow" );
  98    }
  99
 100    mdl_vert   *src_verts =  mdl_submesh_vertices( mdl, sm );
 101    scene_vert *dst_verts = &pscene->arrvertices[ pscene->vertex_count ];
 102
 103    u32 *src_indices    =  mdl_submesh_indices( mdl, sm ),
 104        *dst_indices    = &pscene->arrindices[ pscene->indice_count ];
 105
 106    /* Transform and place vertices */
 107    boxf bbxnew;
 108    box_copy( sm->bbx, bbxnew );
 109    m4x3_transform_aabb( transform, bbxnew );
 110    box_concat( pscene->bbx, bbxnew );
 111
 112    m3x3f normal_matrix;
 113    m3x3_copy( transform, normal_matrix );
 114    v3_normalize( normal_matrix[0] );
 115    v3_normalize( normal_matrix[1] );
 116    v3_normalize( normal_matrix[2] );
 117
 118    for( u32 i=0; i<sm->vertex_count; i++ )
 119    {
 120       mdl_vert   *src   = &src_verts[ i ];
 121       scene_vert *pvert = &dst_verts[ i ];
 122
 123       m4x3_mulv( transform, src->co, pvert->co );
 124
 125       v3f normal;
 126       m3x3_mulv( normal_matrix, src->norm, normal );
 127       scene_vert_pack_norm( pvert, normal );
 128
 129       v2_copy( src->uv, pvert->uv );
 130    }
 131
 132    for( u32 i=0; i<sm->indice_count; i++ )
 133       dst_indices[i] = src_indices[i] + pscene->vertex_count;
 134
 135    pscene->vertex_count += sm->vertex_count;
 136    pscene->indice_count += sm->indice_count;
 137 }
 138
 139 /*
 140  * One by one adders for simplified access (mostly procedural stuff)
 141  */
 142 VG_STATIC void scene_push_tri( scene *pscene, u32 tri[3] )
 143 {
 144    if( pscene->indice_count + 3 > pscene->max_indices )
 145       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 146
 147    u32 *dst = &pscene->arrindices[ pscene->indice_count ];
 148
 149    dst[0] = tri[0];
 150    dst[1] = tri[1];
 151    dst[2] = tri[2];
 152
 153    pscene->indice_count += 3;
 154 }
 155
 156 VG_STATIC void scene_push_vert( scene *pscene, scene_vert *v )
 157 {
 158    if( pscene->vertex_count + 1 > pscene->max_vertices )
 159       vg_fatal_exit_loop( "Scene vertex buffer overflow" );
 160
 161    scene_vert *dst = &pscene->arrvertices[ pscene->vertex_count ];
 162    *dst = *v;
 163
 164    pscene->vertex_count ++;
 165 }
 166
 167 VG_STATIC void scene_copy_slice( scene *pscene, mdl_submesh *sm )
 168 {
 169    sm->indice_start = pscene->submesh.indice_start;
 170    sm->indice_count = pscene->indice_count - sm->indice_start;
 171
 172    sm->vertex_start = pscene->submesh.vertex_start;
 173    sm->vertex_count = pscene->vertex_count - sm->vertex_start;
 174
 175    pscene->submesh.indice_start = pscene->indice_count;
 176    pscene->submesh.vertex_start = pscene->vertex_count;
 177 }
 178
 179 /* finalization: tightly pack data */
 180 __attribute__((warn_unused_result))
 181 VG_STATIC scene *scene_fix( void *lin_alloc, scene *pscene )
 182 {
 183    /* FIXME: Why is this disabled? */
 184
 185    return pscene;
 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_length;
 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    VG_CHECK_GL_ERR();
 263
 264    mesh->indice_count = pscene->indice_count;
 265    mesh->loaded = 1;
 266
 267    vg_info( "Scene upload ( XYZ_f32 UV_f32 XYZW_i8 )[ u32 ]\n" );
 268    vg_info( "   indices:%u\n", pscene->indice_count );
 269    vg_info( "   verts:%u\n",   pscene->vertex_count );
 270 }
 271
 272 /*
 273  * BVH implementation
 274  */
 275
 276 VG_STATIC void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 277 {
 278    scene *s = user;
 279    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 280               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 281               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 282
 283   box_addpt( bound, pa->co );
 284   box_addpt( bound, pb->co );
 285   box_addpt( bound, pc->co );
 286 }
 287
 288 VG_STATIC float scene_bh_centroid( void *user, u32 item_index, int axis )
 289 {
 290    scene *s = user;
 291    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 292               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 293               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 294
 295    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 296 }
 297
 298 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 299 {
 300    scene *s = user;
 301
 302    u32 *ti = &s->arrindices[ia*3];
 303    u32 *tj = &s->arrindices[ib*3];
 304
 305    u32 temp[3];
 306    temp[0] = ti[0];
 307    temp[1] = ti[1];
 308    temp[2] = ti[2];
 309
 310    ti[0] = tj[0];
 311    ti[1] = tj[1];
 312    ti[2] = tj[2];
 313
 314    tj[0] = temp[0];
 315    tj[1] = temp[1];
 316    tj[2] = temp[2];
 317 }
 318
 319 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 320 {
 321    scene *s = user;
 322    u32 idx = item_index*3;
 323    scene_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 324               *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 325               *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 326
 327    vg_line( pa->co, pb->co, 0xff0000ff );
 328    vg_line( pb->co, pc->co, 0xff0000ff );
 329    vg_line( pc->co, pa->co, 0xff0000ff );
 330 }
 331
 332 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 333                             v3f dir, ray_hit *hit )
 334 {
 335    scene *s = user;
 336    v3f positions[3];
 337
 338    u32 *tri = &s->arrindices[ index*3 ];
 339
 340    for( int i=0; i<3; i++ )
 341       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 342
 343    float t;
 344    if(ray_tri( positions, co, dir, &t ))
 345    {
 346       if( t < hit->dist )
 347       {
 348          hit->dist = t;
 349          hit->tri = tri;
 350          return 1;
 351       }
 352    }
 353
 354    return 0;
 355 }
 356
 357 VG_STATIC void scene_bh_closest( void *user, u32 index, v3f point, v3f closest )
 358 {
 359    scene *s = user;
 360
 361    v3f positions[3];
 362    u32 *tri = &s->arrindices[ index*3 ];
 363    for( int i=0; i<3; i++ )
 364       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 365
 366    closest_on_triangle_1( point, positions, closest );
 367 }
 368
 369 VG_STATIC bh_system bh_system_scene =
 370 {
 371    .expand_bound = scene_bh_expand_bound,
 372    .item_centroid = scene_bh_centroid,
 373    .item_closest = scene_bh_closest,
 374    .item_swap = scene_bh_swap,
 375    .item_debug = scene_bh_debug,
 376    .cast_ray = scene_bh_ray
 377 };
 378
 379 /*
 380  * An extra step is added onto the end to calculate the hit normal
 381  */
 382 VG_STATIC int scene_raycast( scene *s, bh_tree *bh,
 383                              v3f co, v3f dir, ray_hit *hit )
 384 {
 385    int count = bh_ray( bh, co, dir, hit );
 386
 387    if( count )
 388    {
 389       v3f v0, v1;
 390
 391       float *pa = s->arrvertices[hit->tri[0]].co,
 392             *pb = s->arrvertices[hit->tri[1]].co,
 393             *pc = s->arrvertices[hit->tri[2]].co;
 394
 395       v3_sub( pa, pb, v0 );
 396       v3_sub( pc, pb, v1 );
 397       v3_cross( v1, v0, hit->normal );
 398       v3_normalize( hit->normal );
 399       v3_muladds( co, dir, hit->dist, hit->pos );
 400    }
 401
 402    return count;
 403 }
 404
 405 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene *s )
 406 {
 407    u32 triangle_count = s->indice_count / 3;
 408    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count, 2 );
 409 }
 410
 411 #endif