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_context scene_context;
   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 /*
  26  * 1. this should probably be a CONTEXT based approach unlike this mess.
  27  * take a bit of the mdl_context ideas and redo this header. its messed up
  28  * pretty bad right now.
  29  */
  30
  31 struct scene_context
  32 {
  33    scene_vert *arrvertices;
  34    u32 *arrindices;
  35
  36    u32 vertex_count, indice_count,
  37        max_vertices, max_indices;
  38
  39    boxf bbx;
  40    mdl_submesh submesh;
  41 };
  42
  43 VG_STATIC u32 scene_mem_required( scene_context *ctx )
  44 {
  45    u32 vertex_length = vg_align8(ctx->max_vertices * sizeof(scene_vert)),
  46        index_length  = vg_align8(ctx->max_indices  * sizeof(u32));
  47
  48    return vertex_length + index_length;
  49 }
  50
  51 VG_STATIC
  52 void scene_init( scene_context *ctx, u32 max_vertices, u32 max_indices )
  53 {
  54    ctx->vertex_count = 0;
  55    ctx->indice_count = 0;
  56    ctx->max_vertices = max_vertices;
  57    ctx->max_indices = max_indices;
  58    ctx->arrindices = NULL; /* must be filled out by user */
  59    ctx->arrvertices = NULL;
  60
  61    memset( &ctx->submesh, 0, sizeof(mdl_submesh) );
  62
  63    v3_fill( ctx->bbx[0],  999999.9f );
  64    v3_fill( ctx->bbx[1], -999999.9f );
  65 }
  66
  67 void scene_supply_buffer( scene_context *ctx, void *buffer )
  68 {
  69    u32 vertex_length = vg_align8( ctx->max_vertices * sizeof(scene_vert) );
  70
  71    ctx->arrvertices = buffer;
  72    ctx->arrindices  = (u32*)(((u8*)buffer) + vertex_length);
  73 }
  74
  75 VG_STATIC void scene_vert_pack_norm( scene_vert *vert, v3f norm )
  76 {
  77    v3f n;
  78    v3_muls( norm, 127.0f, n );
  79    v3_minv( n, (v3f){  127.0f,  127.0f,  127.0f }, n );
  80    v3_maxv( n, (v3f){ -127.0f, -127.0f, -127.0f }, n );
  81    vert->norm[0] = n[0];
  82    vert->norm[1] = n[1];
  83    vert->norm[2] = n[2];
  84    vert->norm[3] = 0;  /* free byte :D */
  85 }
  86
  87 /*
  88  * Append a model into the scene with a given transform
  89  */
  90 VG_STATIC void scene_add_mdl_submesh( scene_context *ctx, mdl_context *mdl,
  91                                       mdl_submesh *sm, m4x3f transform )
  92 {
  93    if( ctx->vertex_count + sm->vertex_count > ctx->max_vertices ){
  94       vg_fatal_error( "Scene vertex buffer overflow (%u exceeds %u)\n",
  95                         ctx->vertex_count + sm->vertex_count,
  96                         ctx->max_vertices );
  97    }
  98
  99    if( ctx->indice_count + sm->indice_count > ctx->max_indices ){
 100       vg_fatal_error( "Scene index buffer overflow (%u exceeds %u)\n",
 101                         ctx->indice_count + sm->indice_count,
 102                         ctx->max_indices );
 103    }
 104
 105    mdl_vert   *src_verts = mdl_arritm( &mdl->verts, sm->vertex_start );
 106    scene_vert *dst_verts = &ctx->arrvertices[ ctx->vertex_count ];
 107
 108    u32 *src_indices    =  mdl_arritm( &mdl->indices, sm->indice_start ),
 109        *dst_indices    = &ctx->arrindices[ ctx->indice_count ];
 110
 111    /* Transform and place vertices */
 112    boxf bbxnew;
 113    box_init_inf( bbxnew );
 114    m4x3_expand_aabb_aabb( transform, bbxnew, sm->bbx );
 115    box_concat( ctx->bbx, bbxnew );
 116
 117    m3x3f normal_matrix;
 118    m3x3_copy( transform, normal_matrix );
 119    v3_normalize( normal_matrix[0] );
 120    v3_normalize( normal_matrix[1] );
 121    v3_normalize( normal_matrix[2] );
 122
 123    for( u32 i=0; i<sm->vertex_count; i++ ){
 124       mdl_vert   *src   = &src_verts[i];
 125       scene_vert *pvert = &dst_verts[i];
 126
 127       m4x3_mulv( transform, src->co, pvert->co );
 128
 129       v3f normal;
 130       m3x3_mulv( normal_matrix, src->norm, normal );
 131       scene_vert_pack_norm( pvert, normal );
 132
 133       v2_copy( src->uv, pvert->uv );
 134    }
 135
 136    u32 real_indices = 0;
 137    for( u32 i=0; i<sm->indice_count/3; i++ ){
 138       u32 *tri = &src_indices[i*3];
 139
 140       v3f ab, ac, tn;
 141       v3_sub( src_verts[tri[2]].co, src_verts[tri[0]].co, ab );
 142       v3_sub( src_verts[tri[1]].co, src_verts[tri[0]].co, ac );
 143       v3_cross( ac, ab, tn );
 144
 145       if( v3_length2( tn ) <= 0.00001f )
 146          continue;
 147
 148       dst_indices[real_indices+0] = tri[0] + ctx->vertex_count;
 149       dst_indices[real_indices+1] = tri[1] + ctx->vertex_count;
 150       dst_indices[real_indices+2] = tri[2] + ctx->vertex_count;
 151
 152       real_indices += 3;
 153    }
 154
 155    if( real_indices != sm->indice_count )
 156       vg_warn( "Zero area triangles in model\n" );
 157
 158    ctx->vertex_count += sm->vertex_count;
 159    ctx->indice_count += real_indices;
 160 }
 161
 162 /*
 163  * One by one adders for simplified access (mostly procedural stuff)
 164  */
 165 VG_STATIC void scene_push_tri( scene_context *ctx, u32 tri[3] )
 166 {
 167    if( ctx->indice_count + 3 > ctx->max_indices )
 168       vg_fatal_error( "Scene indice buffer overflow (%u exceeds %u)\n",
 169                         ctx->indice_count+3, ctx->max_indices );
 170
 171    u32 *dst = &ctx->arrindices[ ctx->indice_count ];
 172
 173    dst[0] = tri[0];
 174    dst[1] = tri[1];
 175    dst[2] = tri[2];
 176
 177    ctx->indice_count += 3;
 178 }
 179
 180 VG_STATIC void scene_push_vert( scene_context *ctx, scene_vert *v )
 181 {
 182    if( ctx->vertex_count + 1 > ctx->max_vertices )
 183       vg_fatal_error( "Scene vertex buffer overflow (%u exceeds %u)\n",
 184                         ctx->vertex_count+1, ctx->max_vertices );
 185
 186    scene_vert *dst = &ctx->arrvertices[ ctx->vertex_count ];
 187    *dst = *v;
 188
 189    ctx->vertex_count ++;
 190 }
 191
 192 VG_STATIC void scene_copy_slice( scene_context *ctx, mdl_submesh *sm )
 193 {
 194    sm->indice_start = ctx->submesh.indice_start;
 195    sm->indice_count = ctx->indice_count - sm->indice_start;
 196
 197    sm->vertex_start = ctx->submesh.vertex_start;
 198    sm->vertex_count = ctx->vertex_count - sm->vertex_start;
 199
 200    ctx->submesh.indice_start = ctx->indice_count;
 201    ctx->submesh.vertex_start = ctx->vertex_count;
 202 }
 203
 204 struct scene_upload_info{
 205    scene_context *ctx;
 206    glmesh *mesh;
 207 };
 208
 209 VG_STATIC void async_scene_upload( void *payload, u32 size )
 210 {
 211    struct scene_upload_info *info = payload;
 212
 213    //assert( mesh->loaded == 0 );
 214
 215    glmesh *mesh = info->mesh;
 216    scene_context *ctx = info->ctx;
 217
 218    glGenVertexArrays( 1, &mesh->vao );
 219    glGenBuffers( 1, &mesh->vbo );
 220    glGenBuffers( 1, &mesh->ebo );
 221    glBindVertexArray( mesh->vao );
 222
 223    size_t stride = sizeof(scene_vert);
 224
 225    glBindBuffer( GL_ARRAY_BUFFER, mesh->vbo );
 226    glBufferData( GL_ARRAY_BUFFER, ctx->vertex_count*stride,
 227                  ctx->arrvertices, GL_STATIC_DRAW );
 228
 229    glBindVertexArray( mesh->vao );
 230    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, mesh->ebo );
 231    glBufferData( GL_ELEMENT_ARRAY_BUFFER, ctx->indice_count*sizeof(u32),
 232                  ctx->arrindices, GL_STATIC_DRAW );
 233
 234    /* 0: coordinates */
 235    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0 );
 236    glEnableVertexAttribArray( 0 );
 237
 238    /* 1: normal */
 239    glVertexAttribPointer( 1, 4, GL_BYTE, GL_TRUE,
 240          stride, (void *)offsetof(scene_vert, norm) );
 241    glEnableVertexAttribArray( 1 );
 242
 243    /* 2: uv */
 244    glVertexAttribPointer( 2, 2, GL_FLOAT, GL_FALSE,
 245          stride, (void *)offsetof(scene_vert, uv) );
 246    glEnableVertexAttribArray( 2 );
 247
 248    VG_CHECK_GL_ERR();
 249
 250    mesh->indice_count = ctx->indice_count;
 251    mesh->loaded = 1;
 252
 253    vg_info( "Scene upload ( XYZ_f32 UV_f32 XYZW_i8 )[ u32 ]\n" );
 254    vg_info( "   indices:%u\n", ctx->indice_count );
 255    vg_info( "   verts:%u\n",   ctx->vertex_count );
 256 }
 257
 258 VG_STATIC void scene_upload_async( scene_context *ctx, glmesh *mesh )
 259 {
 260    vg_async_item *call = vg_async_alloc( sizeof(struct scene_upload_info) );
 261
 262    struct scene_upload_info *info = call->payload;
 263    info->mesh = mesh;
 264    info->ctx = ctx;
 265
 266    vg_async_dispatch( call, async_scene_upload );
 267 }
 268
 269 VG_STATIC
 270 vg_async_item *scene_alloc_async( scene_context *scene, glmesh *mesh,
 271                                   u32 max_vertices, u32 max_indices )
 272 {
 273    scene_init( scene, max_vertices, max_indices );
 274    u32 buf_size = scene_mem_required( scene );
 275
 276    u32 hdr_size = vg_align8(sizeof(struct scene_upload_info));
 277    vg_async_item *call = vg_async_alloc( hdr_size + buf_size );
 278
 279    struct scene_upload_info *info = call->payload;
 280
 281    info->mesh = mesh;
 282    info->ctx = scene;
 283
 284    void *buffer = ((u8*)call->payload)+hdr_size;
 285    scene_supply_buffer( scene, buffer );
 286
 287    return call;
 288 }
 289
 290
 291 /*
 292  * BVH implementation
 293  */
 294
 295 VG_STATIC void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 296 {
 297    scene_context *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   box_addpt( bound, pa->co );
 303   box_addpt( bound, pb->co );
 304   box_addpt( bound, pc->co );
 305 }
 306
 307 VG_STATIC float scene_bh_centroid( void *user, u32 item_index, int axis )
 308 {
 309    scene_context *s = user;
 310    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 311               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 312               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 313
 314    #if 0
 315
 316    float min, max;
 317
 318    min = vg_minf( pa->co[axis], pb->co[axis] );
 319    max = vg_maxf( pa->co[axis], pb->co[axis] );
 320    min = vg_minf( min, pc->co[axis] );
 321    max = vg_maxf( max, pc->co[axis] );
 322
 323    return (min+max) * 0.5f;
 324
 325    #else
 326    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 327    #endif
 328 }
 329
 330 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 331 {
 332    scene_context *s = user;
 333
 334    u32 *ti = &s->arrindices[ia*3];
 335    u32 *tj = &s->arrindices[ib*3];
 336
 337    u32 temp[3];
 338    temp[0] = ti[0];
 339    temp[1] = ti[1];
 340    temp[2] = ti[2];
 341
 342    ti[0] = tj[0];
 343    ti[1] = tj[1];
 344    ti[2] = tj[2];
 345
 346    tj[0] = temp[0];
 347    tj[1] = temp[1];
 348    tj[2] = temp[2];
 349 }
 350
 351 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 352 {
 353    scene_context *s = user;
 354    u32 idx = item_index*3;
 355    scene_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 356               *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 357               *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 358
 359    vg_line( pa->co, pb->co, 0xff0000ff );
 360    vg_line( pb->co, pc->co, 0xff0000ff );
 361    vg_line( pc->co, pa->co, 0xff0000ff );
 362 }
 363
 364 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 365                             v3f dir, ray_hit *hit )
 366 {
 367    scene_context *s = user;
 368    v3f positions[3];
 369
 370    u32 *tri = &s->arrindices[ index*3 ];
 371
 372    for( int i=0; i<3; i++ )
 373       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 374
 375    float t;
 376    if(ray_tri( positions, co, dir, &t )){
 377       if( t < hit->dist ){
 378          hit->dist = t;
 379          hit->tri = tri;
 380          return 1;
 381       }
 382    }
 383
 384    return 0;
 385 }
 386
 387 VG_STATIC void scene_bh_closest( void *user, u32 index, v3f point, v3f closest )
 388 {
 389    scene_context *s = user;
 390
 391    v3f positions[3];
 392    u32 *tri = &s->arrindices[ index*3 ];
 393    for( int i=0; i<3; i++ )
 394       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 395
 396    closest_on_triangle_1( point, positions, closest );
 397 }
 398
 399 VG_STATIC bh_system bh_system_scene =
 400 {
 401    .expand_bound = scene_bh_expand_bound,
 402    .item_centroid = scene_bh_centroid,
 403    .item_closest = scene_bh_closest,
 404    .item_swap = scene_bh_swap,
 405    .item_debug = scene_bh_debug,
 406    .cast_ray = scene_bh_ray
 407 };
 408
 409 /*
 410  * An extra step is added onto the end to calculate the hit normal
 411  */
 412 VG_STATIC int scene_raycast( scene_context *s, bh_tree *bh,
 413                              v3f co, v3f dir, ray_hit *hit )
 414 {
 415    int count = bh_ray( bh, co, dir, hit );
 416
 417    if( count ){
 418       v3f v0, v1;
 419
 420       float *pa = s->arrvertices[hit->tri[0]].co,
 421             *pb = s->arrvertices[hit->tri[1]].co,
 422             *pc = s->arrvertices[hit->tri[2]].co;
 423
 424       v3_sub( pa, pb, v0 );
 425       v3_sub( pc, pb, v1 );
 426       v3_cross( v1, v0, hit->normal );
 427       v3_normalize( hit->normal );
 428       v3_muladds( co, dir, hit->dist, hit->pos );
 429    }
 430
 431    return count;
 432 }
 433
 434 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene_context *s )
 435 {
 436    u32 triangle_count = s->indice_count / 3;
 437    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count, 2 );
 438 }
 439
 440 #endif