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 flags; /* only for the cpu. its junk on the gpu */
  21    u16 unused[3];
  22 };
  23
  24 #pragma pack(pop)
  25
  26 /*
  27  * 1. this should probably be a CONTEXT based approach unlike this mess.
  28  * take a bit of the mdl_context ideas and redo this header. its messed up
  29  * pretty bad right now.
  30  */
  31
  32 struct scene_context
  33 {
  34    scene_vert *arrvertices;
  35    u32 *arrindices;
  36
  37    u32 vertex_count, indice_count,
  38        max_vertices, max_indices;
  39
  40    boxf bbx;
  41    mdl_submesh submesh;
  42 };
  43
  44 static u32 scene_mem_required( scene_context *ctx )
  45 {
  46    u32 vertex_length = vg_align8(ctx->max_vertices * sizeof(scene_vert)),
  47        index_length  = vg_align8(ctx->max_indices  * sizeof(u32));
  48
  49    return vertex_length + index_length;
  50 }
  51
  52 static
  53 void scene_init( scene_context *ctx, u32 max_vertices, u32 max_indices )
  54 {
  55    ctx->vertex_count = 0;
  56    ctx->indice_count = 0;
  57    ctx->max_vertices = max_vertices;
  58    ctx->max_indices = max_indices;
  59    ctx->arrindices = NULL; /* must be filled out by user */
  60    ctx->arrvertices = NULL;
  61
  62    memset( &ctx->submesh, 0, sizeof(mdl_submesh) );
  63
  64    v3_fill( ctx->bbx[0],  999999.9f );
  65    v3_fill( ctx->bbx[1], -999999.9f );
  66 }
  67
  68 void scene_supply_buffer( scene_context *ctx, void *buffer )
  69 {
  70    u32 vertex_length = vg_align8( ctx->max_vertices * sizeof(scene_vert) );
  71
  72    ctx->arrvertices = buffer;
  73    ctx->arrindices  = (u32*)(((u8*)buffer) + vertex_length);
  74 }
  75
  76 static void scene_vert_pack_norm( scene_vert *vert, v3f norm )
  77 {
  78    v3f n;
  79    v3_muls( norm, 127.0f, n );
  80    v3_minv( n, (v3f){  127.0f,  127.0f,  127.0f }, n );
  81    v3_maxv( n, (v3f){ -127.0f, -127.0f, -127.0f }, n );
  82    vert->norm[0] = n[0];
  83    vert->norm[1] = n[1];
  84    vert->norm[2] = n[2];
  85    vert->norm[3] = 0;  /* free byte :D */
  86 }
  87
  88 /*
  89  * Append a model into the scene with a given transform
  90  */
  91 static void scene_add_mdl_submesh( scene_context *ctx, mdl_context *mdl,
  92                                       mdl_submesh *sm, m4x3f transform )
  93 {
  94    if( ctx->vertex_count + sm->vertex_count > ctx->max_vertices ){
  95       vg_fatal_error( "Scene vertex buffer overflow (%u exceeds %u)\n",
  96                         ctx->vertex_count + sm->vertex_count,
  97                         ctx->max_vertices );
  98    }
  99
 100    if( ctx->indice_count + sm->indice_count > ctx->max_indices ){
 101       vg_fatal_error( "Scene index buffer overflow (%u exceeds %u)\n",
 102                         ctx->indice_count + sm->indice_count,
 103                         ctx->max_indices );
 104    }
 105
 106    mdl_vert   *src_verts = mdl_arritm( &mdl->verts, sm->vertex_start );
 107    scene_vert *dst_verts = &ctx->arrvertices[ ctx->vertex_count ];
 108
 109    u32 *src_indices    =  mdl_arritm( &mdl->indices, sm->indice_start ),
 110        *dst_indices    = &ctx->arrindices[ ctx->indice_count ];
 111
 112    /* Transform and place vertices */
 113    boxf bbxnew;
 114    box_init_inf( bbxnew );
 115    m4x3_expand_aabb_aabb( transform, bbxnew, sm->bbx );
 116    box_concat( ctx->bbx, bbxnew );
 117
 118    m3x3f normal_matrix;
 119    m3x3_copy( transform, normal_matrix );
 120    v3_normalize( normal_matrix[0] );
 121    v3_normalize( normal_matrix[1] );
 122    v3_normalize( normal_matrix[2] );
 123
 124    for( u32 i=0; i<sm->vertex_count; i++ ){
 125       mdl_vert   *src   = &src_verts[i];
 126       scene_vert *pvert = &dst_verts[i];
 127
 128       m4x3_mulv( transform, src->co, pvert->co );
 129
 130       v3f normal;
 131       m3x3_mulv( normal_matrix, src->norm, normal );
 132       scene_vert_pack_norm( pvert, normal );
 133
 134       v2_copy( src->uv, pvert->uv );
 135    }
 136
 137    u32 real_indices = 0;
 138    for( u32 i=0; i<sm->indice_count/3; i++ ){
 139       u32 *src = &src_indices[i*3],
 140           *dst = &dst_indices[real_indices];
 141
 142       v3f ab, ac, tn;
 143       v3_sub( src_verts[src[2]].co, src_verts[src[0]].co, ab );
 144       v3_sub( src_verts[src[1]].co, src_verts[src[0]].co, ac );
 145       v3_cross( ac, ab, tn );
 146
 147 #if 0
 148       if( v3_length2( tn ) <= 0.00001f )
 149          continue;
 150 #endif
 151
 152       dst[0] = src[0] + ctx->vertex_count;
 153       dst[1] = src[1] + ctx->vertex_count;
 154       dst[2] = src[2] + ctx->vertex_count;
 155
 156       real_indices += 3;
 157    }
 158
 159    if( real_indices != sm->indice_count )
 160       vg_warn( "Zero area triangles in model\n" );
 161
 162    ctx->vertex_count += sm->vertex_count;
 163    ctx->indice_count += real_indices;
 164 }
 165
 166 /*
 167  * One by one adders for simplified access (mostly procedural stuff)
 168  */
 169 static void scene_push_tri( scene_context *ctx, u32 tri[3] )
 170 {
 171    if( ctx->indice_count + 3 > ctx->max_indices )
 172       vg_fatal_error( "Scene indice buffer overflow (%u exceeds %u)\n",
 173                         ctx->indice_count+3, ctx->max_indices );
 174
 175    u32 *dst = &ctx->arrindices[ ctx->indice_count ];
 176
 177    dst[0] = tri[0];
 178    dst[1] = tri[1];
 179    dst[2] = tri[2];
 180
 181    ctx->indice_count += 3;
 182 }
 183
 184 static void scene_push_vert( scene_context *ctx, scene_vert *v )
 185 {
 186    if( ctx->vertex_count + 1 > ctx->max_vertices )
 187       vg_fatal_error( "Scene vertex buffer overflow (%u exceeds %u)\n",
 188                         ctx->vertex_count+1, ctx->max_vertices );
 189
 190    scene_vert *dst = &ctx->arrvertices[ ctx->vertex_count ];
 191    *dst = *v;
 192
 193    ctx->vertex_count ++;
 194 }
 195
 196 static void scene_copy_slice( scene_context *ctx, mdl_submesh *sm )
 197 {
 198    sm->indice_start = ctx->submesh.indice_start;
 199    sm->indice_count = ctx->indice_count - sm->indice_start;
 200
 201    sm->vertex_start = ctx->submesh.vertex_start;
 202    sm->vertex_count = ctx->vertex_count - sm->vertex_start;
 203
 204    ctx->submesh.indice_start = ctx->indice_count;
 205    ctx->submesh.vertex_start = ctx->vertex_count;
 206 }
 207
 208 static void scene_set_vertex_flags( scene_context *ctx,
 209                                        u32 start, u32 count, u16 flags ){
 210    for( u32 i=0; i<count; i++ )
 211       ctx->arrvertices[ start + i ].flags = flags;
 212 }
 213
 214 struct scene_upload_info{
 215    scene_context *ctx;
 216    glmesh *mesh;
 217 };
 218
 219 static void async_scene_upload( void *payload, u32 size )
 220 {
 221    struct scene_upload_info *info = payload;
 222
 223    //assert( mesh->loaded == 0 );
 224
 225    glmesh *mesh = info->mesh;
 226    scene_context *ctx = info->ctx;
 227
 228    glGenVertexArrays( 1, &mesh->vao );
 229    glGenBuffers( 1, &mesh->vbo );
 230    glGenBuffers( 1, &mesh->ebo );
 231    glBindVertexArray( mesh->vao );
 232
 233    size_t stride = sizeof(scene_vert);
 234
 235    glBindBuffer( GL_ARRAY_BUFFER, mesh->vbo );
 236    glBufferData( GL_ARRAY_BUFFER, ctx->vertex_count*stride,
 237                  ctx->arrvertices, GL_STATIC_DRAW );
 238
 239    glBindVertexArray( mesh->vao );
 240    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, mesh->ebo );
 241    glBufferData( GL_ELEMENT_ARRAY_BUFFER, ctx->indice_count*sizeof(u32),
 242                  ctx->arrindices, GL_STATIC_DRAW );
 243
 244    /* 0: coordinates */
 245    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0 );
 246    glEnableVertexAttribArray( 0 );
 247
 248    /* 1: normal */
 249    glVertexAttribPointer( 1, 4, GL_BYTE, GL_TRUE,
 250          stride, (void *)offsetof(scene_vert, norm) );
 251    glEnableVertexAttribArray( 1 );
 252
 253    /* 2: uv */
 254    glVertexAttribPointer( 2, 2, GL_FLOAT, GL_FALSE,
 255          stride, (void *)offsetof(scene_vert, uv) );
 256    glEnableVertexAttribArray( 2 );
 257
 258    VG_CHECK_GL_ERR();
 259
 260    mesh->indice_count = ctx->indice_count;
 261    mesh->loaded = 1;
 262
 263    vg_info( "Scene upload ( XYZ_f32 UV_f32 XYZW_i8 )[ u32 ]\n" );
 264    vg_info( "   indices:%u\n", ctx->indice_count );
 265    vg_info( "   verts:%u\n",   ctx->vertex_count );
 266 }
 267
 268 static void scene_upload_async( scene_context *ctx, glmesh *mesh )
 269 {
 270    vg_async_item *call = vg_async_alloc( sizeof(struct scene_upload_info) );
 271
 272    struct scene_upload_info *info = call->payload;
 273    info->mesh = mesh;
 274    info->ctx = ctx;
 275
 276    vg_async_dispatch( call, async_scene_upload );
 277 }
 278
 279 static
 280 vg_async_item *scene_alloc_async( scene_context *scene, glmesh *mesh,
 281                                   u32 max_vertices, u32 max_indices )
 282 {
 283    scene_init( scene, max_vertices, max_indices );
 284    u32 buf_size = scene_mem_required( scene );
 285
 286    u32 hdr_size = vg_align8(sizeof(struct scene_upload_info));
 287    vg_async_item *call = vg_async_alloc( hdr_size + buf_size );
 288
 289    struct scene_upload_info *info = call->payload;
 290
 291    info->mesh = mesh;
 292    info->ctx = scene;
 293
 294    void *buffer = ((u8*)call->payload)+hdr_size;
 295    scene_supply_buffer( scene, buffer );
 296
 297    return call;
 298 }
 299
 300
 301 /*
 302  * BVH implementation
 303  */
 304
 305 static void scene_bh_expand_bound( void *user, boxf bound, u32 item_index )
 306 {
 307    scene_context *s = user;
 308    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 309               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 310               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 311
 312   box_addpt( bound, pa->co );
 313   box_addpt( bound, pb->co );
 314   box_addpt( bound, pc->co );
 315 }
 316
 317 static float scene_bh_centroid( void *user, u32 item_index, int axis )
 318 {
 319    scene_context *s = user;
 320    scene_vert *pa = &s->arrvertices[ s->arrindices[item_index*3+0] ],
 321               *pb = &s->arrvertices[ s->arrindices[item_index*3+1] ],
 322               *pc = &s->arrvertices[ s->arrindices[item_index*3+2] ];
 323
 324    #if 0
 325
 326    float min, max;
 327
 328    min = vg_minf( pa->co[axis], pb->co[axis] );
 329    max = vg_maxf( pa->co[axis], pb->co[axis] );
 330    min = vg_minf( min, pc->co[axis] );
 331    max = vg_maxf( max, pc->co[axis] );
 332
 333    return (min+max) * 0.5f;
 334
 335    #else
 336    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 337    #endif
 338 }
 339
 340 static void scene_bh_swap( void *user, u32 ia, u32 ib )
 341 {
 342    scene_context *s = user;
 343
 344    u32 *ti = &s->arrindices[ia*3];
 345    u32 *tj = &s->arrindices[ib*3];
 346
 347    u32 temp[3];
 348    temp[0] = ti[0];
 349    temp[1] = ti[1];
 350    temp[2] = ti[2];
 351
 352    ti[0] = tj[0];
 353    ti[1] = tj[1];
 354    ti[2] = tj[2];
 355
 356    tj[0] = temp[0];
 357    tj[1] = temp[1];
 358    tj[2] = temp[2];
 359 }
 360
 361 static void scene_bh_debug( void *user, u32 item_index )
 362 {
 363    scene_context *s = user;
 364    u32 idx = item_index*3;
 365    scene_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 366               *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 367               *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 368
 369    vg_line( pa->co, pb->co, 0xff0000ff );
 370    vg_line( pb->co, pc->co, 0xff0000ff );
 371    vg_line( pc->co, pa->co, 0xff0000ff );
 372 }
 373
 374 static void scene_bh_closest( void *user, u32 index, v3f point, v3f closest )
 375 {
 376    scene_context *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 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 };
 394
 395 /*
 396  * An extra step is added onto the end to calculate the hit normal
 397  */
 398 static int scene_raycast( scene_context *s, bh_tree *bh,
 399                              v3f co, v3f dir, ray_hit *hit, u16 ignore )
 400 {
 401    hit->tri = NULL;
 402
 403    bh_iter it;
 404    bh_iter_init_ray( 0, &it, co, dir, hit->dist );
 405    i32 idx;
 406
 407    while( bh_next( bh, &it, &idx ) ){
 408       u32 *tri = &s->arrindices[ idx*3 ];
 409
 410       if( s->arrvertices[tri[0]].flags & ignore )  continue;
 411
 412       v3f vs[3];
 413       for( u32 i=0; i<3; i++ )
 414          v3_copy( s->arrvertices[tri[i]].co, vs[i] );
 415
 416       f32 t;
 417       if( ray_tri( vs, co, dir, &t ) ){
 418          if( t < hit->dist ){
 419             hit->dist = t;
 420             hit->tri = tri;
 421          }
 422       }
 423    }
 424
 425    if( hit->tri ){
 426       v3f v0, v1;
 427
 428       float *pa = s->arrvertices[hit->tri[0]].co,
 429             *pb = s->arrvertices[hit->tri[1]].co,
 430             *pc = s->arrvertices[hit->tri[2]].co;
 431
 432       v3_sub( pa, pb, v0 );
 433       v3_sub( pc, pb, v1 );
 434       v3_cross( v1, v0, hit->normal );
 435       v3_normalize( hit->normal );
 436       v3_muladds( co, dir, hit->dist, hit->pos );
 437    }
 438
 439    return hit->tri?1:0;
 440 }
 441
 442 static bh_tree *scene_bh_create( void *lin_alloc, scene_context *s )
 443 {
 444    u32 triangle_count = s->indice_count / 3;
 445    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count, 2 );
 446 }
 447
 448 #endif