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_copy( sm->bbx, bbxnew );
 114    m4x3_transform_aabb( transform, bbxnew );
 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    for( u32 i=0; i<sm->indice_count; i++ )
 137       dst_indices[i] = src_indices[i] + ctx->vertex_count;
 138
 139    ctx->vertex_count += sm->vertex_count;
 140    ctx->indice_count += sm->indice_count;
 141 }
 142
 143 /*
 144  * One by one adders for simplified access (mostly procedural stuff)
 145  */
 146 VG_STATIC void scene_push_tri( scene_context *ctx, u32 tri[3] )
 147 {
 148    if( ctx->indice_count + 3 > ctx->max_indices )
 149       vg_fatal_error( "Scene indice buffer overflow (%u exceeds %u)\n",
 150                         ctx->indice_count+3, ctx->max_indices );
 151
 152    u32 *dst = &ctx->arrindices[ ctx->indice_count ];
 153
 154    dst[0] = tri[0];
 155    dst[1] = tri[1];
 156    dst[2] = tri[2];
 157
 158    ctx->indice_count += 3;
 159 }
 160
 161 VG_STATIC void scene_push_vert( scene_context *ctx, scene_vert *v )
 162 {
 163    if( ctx->vertex_count + 1 > ctx->max_vertices )
 164       vg_fatal_error( "Scene vertex buffer overflow (%u exceeds %u)\n",
 165                         ctx->vertex_count+1, ctx->max_vertices );
 166
 167    scene_vert *dst = &ctx->arrvertices[ ctx->vertex_count ];
 168    *dst = *v;
 169
 170    ctx->vertex_count ++;
 171 }
 172
 173 VG_STATIC void scene_copy_slice( scene_context *ctx, mdl_submesh *sm )
 174 {
 175    sm->indice_start = ctx->submesh.indice_start;
 176    sm->indice_count = ctx->indice_count - sm->indice_start;
 177
 178    sm->vertex_start = ctx->submesh.vertex_start;
 179    sm->vertex_count = ctx->vertex_count - sm->vertex_start;
 180
 181    ctx->submesh.indice_start = ctx->indice_count;
 182    ctx->submesh.vertex_start = ctx->vertex_count;
 183 }
 184
 185 struct scene_upload_info{
 186    scene_context *ctx;
 187    glmesh *mesh;
 188 };
 189
 190 VG_STATIC void async_scene_upload( void *payload, u32 size )
 191 {
 192    struct scene_upload_info *info = payload;
 193
 194    //assert( mesh->loaded == 0 );
 195
 196    glmesh *mesh = info->mesh;
 197    scene_context *ctx = info->ctx;
 198
 199    glGenVertexArrays( 1, &mesh->vao );
 200    glGenBuffers( 1, &mesh->vbo );
 201    glGenBuffers( 1, &mesh->ebo );
 202    glBindVertexArray( mesh->vao );
 203
 204    size_t stride = sizeof(scene_vert);
 205
 206    glBindBuffer( GL_ARRAY_BUFFER, mesh->vbo );
 207    glBufferData( GL_ARRAY_BUFFER, ctx->vertex_count*stride,
 208                  ctx->arrvertices, GL_STATIC_DRAW );
 209
 210    glBindVertexArray( mesh->vao );
 211    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, mesh->ebo );
 212    glBufferData( GL_ELEMENT_ARRAY_BUFFER, ctx->indice_count*sizeof(u32),
 213                  ctx->arrindices, GL_STATIC_DRAW );
 214
 215    /* 0: coordinates */
 216    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0 );
 217    glEnableVertexAttribArray( 0 );
 218
 219    /* 1: normal */
 220    glVertexAttribPointer( 1, 4, GL_BYTE, GL_TRUE,
 221          stride, (void *)offsetof(scene_vert, norm) );
 222    glEnableVertexAttribArray( 1 );
 223
 224    /* 2: uv */
 225    glVertexAttribPointer( 2, 2, GL_FLOAT, GL_FALSE,
 226          stride, (void *)offsetof(scene_vert, uv) );
 227    glEnableVertexAttribArray( 2 );
 228
 229    VG_CHECK_GL_ERR();
 230
 231    mesh->indice_count = ctx->indice_count;
 232    mesh->loaded = 1;
 233
 234    vg_info( "Scene upload ( XYZ_f32 UV_f32 XYZW_i8 )[ u32 ]\n" );
 235    vg_info( "   indices:%u\n", ctx->indice_count );
 236    vg_info( "   verts:%u\n",   ctx->vertex_count );
 237 }
 238
 239 VG_STATIC void scene_upload_async( scene_context *ctx, glmesh *mesh )
 240 {
 241    vg_async_item *call = vg_async_alloc( sizeof(struct scene_upload_info) );
 242
 243    struct scene_upload_info *info = call->payload;
 244    info->mesh = mesh;
 245    info->ctx = ctx;
 246
 247    vg_async_dispatch( call, async_scene_upload );
 248 }
 249
 250 VG_STATIC
 251 vg_async_item *scene_alloc_async( scene_context *scene, glmesh *mesh,
 252                                   u32 max_vertices, u32 max_indices )
 253 {
 254    scene_init( scene, max_vertices, max_indices );
 255    u32 buf_size = scene_mem_required( scene );
 256
 257    u32 hdr_size = vg_align8(sizeof(struct scene_upload_info));
 258    vg_async_item *call = vg_async_alloc( hdr_size + buf_size );
 259
 260    struct scene_upload_info *info = call->payload;
 261
 262    info->mesh = mesh;
 263    info->ctx = scene;
 264
 265    void *buffer = ((u8*)call->payload)+hdr_size;
 266    scene_supply_buffer( scene, buffer );
 267
 268    return call;
 269 }
 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_context *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_context *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    #if 0
 296
 297    float min, max;
 298
 299    min = vg_minf( pa->co[axis], pb->co[axis] );
 300    max = vg_maxf( pa->co[axis], pb->co[axis] );
 301    min = vg_minf( min, pc->co[axis] );
 302    max = vg_maxf( max, pc->co[axis] );
 303
 304    return (min+max) * 0.5f;
 305
 306    #else
 307    return (pa->co[axis] + pb->co[axis] + pc->co[axis]) * (1.0f/3.0f);
 308    #endif
 309 }
 310
 311 VG_STATIC void scene_bh_swap( void *user, u32 ia, u32 ib )
 312 {
 313    scene_context *s = user;
 314
 315    u32 *ti = &s->arrindices[ia*3];
 316    u32 *tj = &s->arrindices[ib*3];
 317
 318    u32 temp[3];
 319    temp[0] = ti[0];
 320    temp[1] = ti[1];
 321    temp[2] = ti[2];
 322
 323    ti[0] = tj[0];
 324    ti[1] = tj[1];
 325    ti[2] = tj[2];
 326
 327    tj[0] = temp[0];
 328    tj[1] = temp[1];
 329    tj[2] = temp[2];
 330 }
 331
 332 VG_STATIC void scene_bh_debug( void *user, u32 item_index )
 333 {
 334    scene_context *s = user;
 335    u32 idx = item_index*3;
 336    scene_vert *pa = &s->arrvertices[ s->arrindices[ idx+0 ] ],
 337               *pb = &s->arrvertices[ s->arrindices[ idx+1 ] ],
 338               *pc = &s->arrvertices[ s->arrindices[ idx+2 ] ];
 339
 340    vg_line( pa->co, pb->co, 0xff0000ff );
 341    vg_line( pb->co, pc->co, 0xff0000ff );
 342    vg_line( pc->co, pa->co, 0xff0000ff );
 343 }
 344
 345 VG_STATIC int scene_bh_ray( void *user, u32 index, v3f co,
 346                             v3f dir, ray_hit *hit )
 347 {
 348    scene_context *s = user;
 349    v3f positions[3];
 350
 351    u32 *tri = &s->arrindices[ index*3 ];
 352
 353    for( int i=0; i<3; i++ )
 354       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 355
 356    float t;
 357    if(ray_tri( positions, co, dir, &t )){
 358       if( t < hit->dist ){
 359          hit->dist = t;
 360          hit->tri = tri;
 361          return 1;
 362       }
 363    }
 364
 365    return 0;
 366 }
 367
 368 VG_STATIC void scene_bh_closest( void *user, u32 index, v3f point, v3f closest )
 369 {
 370    scene_context *s = user;
 371
 372    v3f positions[3];
 373    u32 *tri = &s->arrindices[ index*3 ];
 374    for( int i=0; i<3; i++ )
 375       v3_copy( s->arrvertices[tri[i]].co, positions[i] );
 376
 377    closest_on_triangle_1( point, positions, closest );
 378 }
 379
 380 VG_STATIC bh_system bh_system_scene =
 381 {
 382    .expand_bound = scene_bh_expand_bound,
 383    .item_centroid = scene_bh_centroid,
 384    .item_closest = scene_bh_closest,
 385    .item_swap = scene_bh_swap,
 386    .item_debug = scene_bh_debug,
 387    .cast_ray = scene_bh_ray
 388 };
 389
 390 /*
 391  * An extra step is added onto the end to calculate the hit normal
 392  */
 393 VG_STATIC int scene_raycast( scene_context *s, bh_tree *bh,
 394                              v3f co, v3f dir, ray_hit *hit )
 395 {
 396    int count = bh_ray( bh, co, dir, hit );
 397
 398    if( count ){
 399       v3f v0, v1;
 400
 401       float *pa = s->arrvertices[hit->tri[0]].co,
 402             *pb = s->arrvertices[hit->tri[1]].co,
 403             *pc = s->arrvertices[hit->tri[2]].co;
 404
 405       v3_sub( pa, pb, v0 );
 406       v3_sub( pc, pb, v1 );
 407       v3_cross( v1, v0, hit->normal );
 408       v3_normalize( hit->normal );
 409       v3_muladds( co, dir, hit->dist, hit->pos );
 410    }
 411
 412    return count;
 413 }
 414
 415 VG_STATIC bh_tree *scene_bh_create( void *lin_alloc, scene_context *s )
 416 {
 417    u32 triangle_count = s->indice_count / 3;
 418    return bh_create( lin_alloc, &bh_system_scene, s, triangle_count, 2 );
 419 }
 420
 421 #endif