world.h

   1 /*
   2  * Copyright (C) 2021-2022 Mt.ZERO Software, Harry Godden - All Rights Reserved
   3  */
   4
   5 #include "common.h"
   6
   7 #ifndef WORLD_H
   8 #define WORLD_H
   9
  10 typedef struct world_instance world_instance;
  11
  12 #include "vg/vg_loader.h"
  13
  14 #include "network.h"
  15 #include "network_msg.h"
  16 #include "scene.h"
  17 #include "render.h"
  18 #include "rigidbody.h"
  19 #include "bvh.h"
  20 #include "model.h"
  21 #include "entity.h"
  22 #include "font.h"
  23
  24 #include "shaders/scene_standard.h"
  25 #include "shaders/scene_standard_alphatest.h"
  26 #include "shaders/scene_vertex_blend.h"
  27 #include "shaders/scene_terrain.h"
  28 #include "shaders/scene_depth.h"
  29 #include "shaders/scene_position.h"
  30
  31 #include "shaders/model_sky.h"
  32
  33 enum { k_max_ui_segments = 8 };
  34
  35 enum { k_max_ui_elements = k_max_ui_segments };
  36 enum { k_max_element_verts = 10 };
  37 enum { k_max_element_indices = 20 };
  38
  39 enum { k_route_ui_max_verts = k_max_ui_elements*k_max_element_verts };
  40 enum { k_route_ui_max_indices = k_max_ui_elements*k_max_element_indices };
  41
  42 enum logic_type
  43 {
  44    k_logic_type_relay         = 1,
  45    k_logic_type_chance        = 2,
  46    k_logic_type_achievement   = 3
  47 };
  48
  49 enum geo_type
  50 {
  51    k_geo_type_solid = 0,
  52    k_geo_type_nonsolid = 1,
  53    k_geo_type_water = 2
  54 };
  55
  56 static const float k_light_cube_size = 8.0f;
  57
  58 struct world_instance {
  59    /* Fixed items
  60     * -------------------------------------------------------
  61     */
  62
  63    char  world_name[ 64 ];
  64
  65    struct{
  66       boxf depthbounds;
  67       int depth_computed;
  68
  69       float height;
  70       int enabled;
  71       v4f plane;
  72    }
  73    water;
  74
  75    /* STD140 */
  76    struct ub_world_lighting{
  77       v4f g_cube_min,
  78           g_cube_inv_range;
  79
  80       v4f g_water_plane,
  81           g_depth_bounds;
  82
  83       v4f g_daysky_colour;
  84       v4f g_nightsky_colour;
  85       v4f g_sunset_colour;
  86       v4f g_ambient_colour;
  87       v4f g_sunset_ambient;
  88       v4f g_sun_colour;
  89       v4f g_sun_dir;
  90
  91       float g_water_fog;
  92       float g_time;
  93       float g_realtime;
  94       float g_shadow_length;
  95       float g_shadow_spread;
  96
  97       float g_time_of_day;
  98       float g_day_phase;
  99       float g_sunset_phase;
 100
 101       int g_light_preview;
 102       int g_shadow_samples;
 103
 104       int g_debug_indices;
 105       int g_debug_complexity;
 106    }
 107    ub_lighting;
 108    GLuint ubo_lighting;
 109    int    ubo_bind_point;
 110
 111    GLuint tbo_light_entities,
 112           tex_light_entities,
 113           tex_light_cubes;
 114
 115    float probabilities[3];
 116
 117    v3i light_cubes;
 118
 119    struct framebuffer heightmap;
 120
 121    /*
 122     * Dynamically allocated when world_load is called.
 123     *
 124     *                  the following arrays index somewhere into this linear
 125     *                  allocator
 126     *
 127     * (world_gen.h)
 128     * --------------------------------------------------------------------------
 129     */
 130
 131    /*
 132     * Main world .mdl
 133     */
 134    mdl_context meta;
 135
 136    GLuint *textures;
 137    u32 texture_count;
 138
 139    struct world_surface{
 140       mdl_material info;
 141       mdl_submesh sm_geo,
 142                   sm_no_collide;
 143    }
 144    * surfaces;
 145    u32 surface_count;
 146
 147    mdl_array_ptr ent_spawn,
 148                  ent_gate,
 149                  ent_light,
 150                  ent_route_node,
 151                  ent_path_index,
 152                  ent_checkpoint,
 153                  ent_route,
 154                  ent_water,
 155
 156                  ent_audio_clip,
 157                  ent_audio,
 158                  ent_volume;
 159
 160    ent_gate *rendering_gate;
 161
 162    /* logic
 163     * ----------------------------------------------------
 164     */
 165
 166    /* world geometry */
 167    scene *scene_geo,
 168          *scene_no_collide,
 169          *scene_lines;
 170
 171    /* spacial mappings */
 172    bh_tree *audio_bh,
 173            *volume_bh,
 174            *geo_bh;
 175
 176    /* graphics */
 177    glmesh mesh_route_lines;
 178    glmesh mesh_geo,
 179           mesh_no_collide,
 180           mesh_water;
 181
 182    rb_object rb_geo;
 183 };
 184
 185 VG_STATIC struct world_global{
 186    /*
 187     * Allocated as system memory
 188     * --------------------------------------------------------------------------
 189     */
 190    void *generic_heap;
 191
 192    /* rendering */
 193    glmesh skydome;
 194    glmesh mesh_gate;
 195    mdl_submesh sm_gate_surface,
 196                sm_gate_marker[4];
 197
 198    double sky_time, sky_rate, sky_target_rate;
 199
 200    u32 current_run_version;
 201    double time, rewind_from, rewind_to, last_use;
 202
 203    /* water rendering */
 204    struct{
 205       struct framebuffer fbreflect, fbdepth;
 206    }
 207    water;
 208
 209    /* split flap display */
 210    struct{
 211       glmesh mesh_base, mesh_display;
 212       mdl_submesh sm_base;
 213       u32 active_route_board;
 214
 215       u32 w, h;
 216       float *buffer;
 217    }
 218    sfd;
 219
 220    v3f render_gate_pos;
 221    int in_volume;
 222
 223    int switching_to_new_world;
 224
 225    world_instance worlds[4];
 226    u32            world_count;
 227    u32            active_world;
 228
 229    /* text particles */
 230    font3d font;
 231
 232    struct timer_text{
 233       char text[8];
 234       m4x3f transform;
 235       ent_gate *gate;
 236       ent_route *route;
 237    }
 238    timer_texts[4];
 239    u32 timer_text_count;
 240
 241    struct text_particle{
 242       rigidbody *rb;
 243       ent_glyph *glyph;
 244    }
 245    text_particles[6*4];
 246    u32 text_particle_count;
 247
 248 }
 249 world_global;
 250
 251 VG_STATIC world_instance *get_active_world( void )
 252 {
 253    return &world_global.worlds[ world_global.active_world ];
 254 }
 255
 256 /*
 257  * API
 258  */
 259
 260 VG_STATIC
 261 int ray_hit_is_ramp( world_instance *world, ray_hit *hit );
 262
 263 VG_STATIC
 264 struct world_surface *ray_hit_surface( world_instance *world, ray_hit *hit );
 265
 266 VG_STATIC
 267 void ray_world_get_tri( world_instance *world, ray_hit *hit, v3f tri[3] );
 268
 269 VG_STATIC
 270 int ray_world( world_instance *world, v3f pos, v3f dir, ray_hit *hit );
 271
 272 /*
 273  * Submodules
 274  */
 275
 276 #include "world_routes.h"
 277 #include "world_sfd.h"
 278 #include "world_render.h"
 279 #include "world_water.h"
 280 #include "world_volumes.h"
 281 #include "world_gen.h"
 282 #include "world_gate.h"
 283
 284 /*
 285  * -----------------------------------------------------------------------------
 286  *                                    Events
 287  * -----------------------------------------------------------------------------
 288  */
 289
 290 VG_STATIC int world_stop_sound( int argc, const char *argv[] )
 291 {
 292    world_instance *world = get_active_world();
 293    return 0;
 294 }
 295
 296 VG_STATIC void world_init(void)
 297 {
 298    world_global.sky_rate = 1.0;
 299    world_global.sky_target_rate = 1.0;
 300
 301    shader_scene_standard_register();
 302    shader_scene_standard_alphatest_register();
 303    shader_scene_vertex_blend_register();
 304    shader_scene_terrain_register();
 305    shader_scene_depth_register();
 306    shader_scene_position_register();
 307
 308    shader_model_sky_register();
 309
 310    vg_info( "Loading world resources\n" );
 311
 312    vg_linear_clear( vg_mem.scratch );
 313
 314    mdl_context msky;
 315    mdl_open( &msky, "models/rs_skydome.mdl", vg_mem.scratch );
 316    mdl_load_metadata_block( &msky, vg_mem.scratch );
 317    mdl_load_mesh_block( &msky, vg_mem.scratch );
 318    mdl_close( &msky );
 319
 320    vg_acquire_thread_sync();
 321    {
 322       mdl_unpack_glmesh( &msky, &world_global.skydome );
 323    }
 324    vg_release_thread_sync();
 325
 326    /* Other systems */
 327    vg_info( "Loading other world systems\n" );
 328
 329    vg_loader_step( world_render_init, NULL );
 330    vg_loader_step( world_sfd_init, NULL );
 331    vg_loader_step( world_water_init, NULL );
 332    vg_loader_step( world_gates_init, NULL );
 333    vg_loader_step( world_routes_init, NULL );
 334
 335    /* Allocate dynamic world memory arena */
 336    u32 max_size = 76*1024*1024;
 337    world_global.generic_heap = vg_create_linear_allocator( vg_mem.rtmemory,
 338                                                            max_size,
 339                                                            VG_MEMORY_SYSTEM );
 340 }
 341
 342 typedef struct ent_call ent_call;
 343 struct ent_call{
 344    ent_index ent;
 345    u32 function;
 346    void *data;
 347 };
 348
 349 VG_STATIC void entity_call( world_instance *world, ent_call *call );
 350
 351 VG_STATIC void ent_volume_call( world_instance *world, ent_call *call )
 352 {
 353    ent_volume *volume = mdl_arritm( &world->ent_volume, call->ent.index );
 354    if( !volume->target.type ) return;
 355
 356    if( call->function == k_ent_function_trigger ){
 357       call->ent = volume->target;
 358
 359       if( volume->type == k_volume_subtype_particle ){
 360          float *co = alloca( sizeof(float)*3 );
 361          co[0] = vg_randf()*2.0f-1.0f;
 362          co[1] = vg_randf()*2.0f-1.0f;
 363          co[2] = vg_randf()*2.0f-1.0f;
 364          m4x3_mulv( volume->to_world, co, co );
 365
 366          call->function = k_ent_function_particle_spawn;
 367          call->data = co;
 368          entity_call( world, call );
 369       }
 370       else
 371          entity_call( world, call );
 372    }
 373 }
 374
 375 VG_STATIC void ent_audio_call( world_instance *world, ent_call *call )
 376 {
 377    ent_audio *audio = mdl_arritm( &world->ent_audio, call->ent.index );
 378
 379    v3f sound_co;
 380
 381    if( call->function == k_ent_function_particle_spawn ){
 382       v3_copy( call->data, sound_co );
 383    }
 384    else if( call->function == k_ent_function_trigger ){
 385       v3_copy( audio->transform.co, sound_co );
 386    }
 387    else
 388       vg_fatal_exit_loop( "ent_audio_call (invalid function id)" );
 389
 390    float chance = vg_randf()*100.0f,
 391          bar = 0.0f;
 392
 393    for( u32 i=0; i<audio->clip_count; i++ ){
 394       ent_audio_clip *clip = mdl_arritm( &world->ent_audio_clip,
 395                                           audio->clip_start+i );
 396
 397       float mod = world->probabilities[ audio->probability_curve ],
 398             p   = clip->probability * mod;
 399
 400       bar += p;
 401
 402       if( chance < bar ){
 403
 404          audio_lock();
 405
 406          if( audio->behaviour == k_channel_behaviour_unlimited ){
 407             audio_oneshot_3d( &clip->clip, sound_co,
 408                               audio->transform.s[0],
 409                               audio->volume );
 410          }
 411          else if( audio->behaviour == k_channel_behaviour_discard_if_full ){
 412             audio_channel *ch =
 413                audio_get_group_idle_channel( audio->group,
 414                                              audio->max_channels );
 415
 416             if( ch ){
 417                audio_channel_init( ch, &clip->clip, audio->flags );
 418                audio_channel_group( ch, audio->group );
 419                audio_channel_set_spacial( ch, sound_co, audio->transform.s[0] );
 420                audio_channel_edit_volume( ch, audio->volume, 1 );
 421                ch = audio_relinquish_channel( ch );
 422             }
 423          }
 424          else if( audio->behaviour == k_channel_behaviour_crossfade_if_full){
 425             audio_channel *ch =
 426                audio_get_group_idle_channel( audio->group,
 427                                              audio->max_channels );
 428
 429             /* group is full */
 430             if( !ch ){
 431                audio_channel *existing =
 432                   audio_get_group_first_active_channel( audio->group );
 433
 434                if( existing ){
 435                   if( existing->source == &clip->clip ){
 436                      audio_unlock();
 437                      return;
 438                   }
 439
 440                   existing->group = 0;
 441                   existing = audio_channel_fadeout(existing, audio->crossfade);
 442                }
 443
 444                ch = audio_get_first_idle_channel();
 445             }
 446
 447             if( ch ){
 448                audio_channel_init( ch, &clip->clip, audio->flags );
 449                audio_channel_group( ch, audio->group );
 450                audio_channel_fadein( ch, audio->crossfade );
 451                ch = audio_relinquish_channel( ch );
 452             }
 453          }
 454
 455          audio_unlock();
 456          return;
 457       }
 458    }
 459 }
 460
 461 VG_STATIC void entity_call( world_instance *world, ent_call *call )
 462 {
 463    if( call->ent.type == k_ent_volume ){
 464       ent_volume_call( world, call );
 465    } else if( call->ent.type == k_ent_audio ){
 466       ent_audio_call( world, call );
 467    }
 468 }
 469
 470 VG_STATIC void world_update( world_instance *world, v3f pos )
 471 {
 472    /* TEMP!!!!!! */
 473    static double g_time = 0.0;
 474    g_time += vg.time_delta * (1.0/(k_day_length*60.0));
 475
 476
 477    struct ub_world_lighting *state = &world->ub_lighting;
 478
 479    state->g_time = g_time;
 480    state->g_realtime = vg.time;
 481    state->g_debug_indices = k_debug_light_indices;
 482    state->g_light_preview = k_light_preview;
 483    state->g_debug_complexity = k_debug_light_complexity;
 484
 485    state->g_time_of_day = vg_fractf( g_time );
 486    state->g_day_phase   = cosf( state->g_time_of_day * VG_PIf * 2.0f );
 487    state->g_sunset_phase= cosf( state->g_time_of_day * VG_PIf * 4.0f + VG_PIf );
 488
 489    state->g_day_phase    =       state->g_day_phase    * 0.5f + 0.5f;
 490    state->g_sunset_phase = powf( state->g_sunset_phase * 0.5f + 0.5f, 6.0f );
 491
 492    float a = state->g_time_of_day * VG_PIf * 2.0f;
 493    state->g_sun_dir[0] = sinf( a );
 494    state->g_sun_dir[1] = cosf( a );
 495    state->g_sun_dir[2] = 0.2f;
 496    v3_normalize( state->g_sun_dir );
 497
 498
 499    world->probabilities[ k_probability_curve_constant ] = 1.0f;
 500
 501    float dp = state->g_day_phase;
 502
 503    world->probabilities[ k_probability_curve_wildlife_day ] =
 504       (dp*dp*0.8f+state->g_sunset_phase)*0.8f;
 505    world->probabilities[ k_probability_curve_wildlife_night ] =
 506       1.0f-powf(fabsf((state->g_time_of_day-0.5f)*5.0f),5.0f);
 507
 508
 509    glBindBuffer( GL_UNIFORM_BUFFER, world->ubo_lighting );
 510    glBufferSubData( GL_UNIFORM_BUFFER, 0,
 511                     sizeof(struct ub_world_lighting), &world->ub_lighting );
 512    /* TEMP!!!!!! */
 513
 514    world_global.sky_time += world_global.sky_rate * vg.time_delta;
 515    world_global.sky_rate = vg_lerp( world_global.sky_rate,
 516                                     world_global.sky_target_rate,
 517                                     vg.time_delta * 5.0 );
 518
 519    world_routes_update_timer_texts( world );
 520    world_routes_update( world );
 521    //world_routes_debug( world );
 522
 523    /* ---- SFD ------------ */
 524
 525    if( mdl_arrcount( &world->ent_route ) ){
 526       u32 closest = 0;
 527       float min_dist = INFINITY;
 528
 529       for( u32 i=0; i<mdl_arrcount( &world->ent_route ); i++ ){
 530          ent_route *route = mdl_arritm( &world->ent_route, i );
 531          float dist = v3_dist2( route->board_transform[3], pos );
 532
 533          if( dist < min_dist ){
 534             min_dist = dist;
 535             closest = i;
 536          }
 537       }
 538
 539       if( (world_global.sfd.active_route_board != closest)
 540           || network_scores_updated )
 541       {
 542          network_scores_updated = 0;
 543          world_global.sfd.active_route_board = closest;
 544
 545          ent_route *route = mdl_arritm( &world->ent_route, closest );
 546          u32 id = route->official_track_id;
 547
 548          if( id != 0xffffffff ){
 549             struct netmsg_board *local_board =
 550                &scoreboard_client_data.boards[id];
 551
 552             for( int i=0; i<13; i++ ){
 553                sfd_encode( i, &local_board->data[27*i] );
 554             }
 555          }else{
 556             sfd_encode( 0, mdl_pstr( &world->meta, route->pstr_name ) );
 557             sfd_encode( 1, "No data" );
 558          }
 559       }
 560    }
 561    sfd_update();
 562
 563
 564
 565    static float random_accum = 0.0f;
 566    random_accum += vg.time_delta;
 567
 568    u32 random_ticks = 0;
 569
 570    while( random_accum > 0.1f ){
 571       random_accum -= 0.1f;
 572       random_ticks ++;
 573    }
 574
 575    float radius = 25.0f;
 576    boxf volume_proximity;
 577    v3_add( pos, (v3f){ radius, radius, radius }, volume_proximity[1] );
 578    v3_sub( pos, (v3f){ radius, radius, radius }, volume_proximity[0] );
 579
 580    bh_iter it;
 581    bh_iter_init( 0, &it );
 582    int idx;
 583
 584    int in_volume = 0;
 585
 586    while( bh_next( world->volume_bh, &it, volume_proximity, &idx ) ){
 587       ent_volume *volume = mdl_arritm( &world->ent_volume, idx );
 588
 589       boxf cube = {{-1.0f,-1.0f,-1.0f},{1.0f,1.0f,1.0f}};
 590
 591       if( volume->type == k_volume_subtype_trigger ){
 592          v3f local;
 593          m4x3_mulv( volume->to_local, pos, local );
 594
 595          if( (fabsf(local[0]) <= 1.0f) &&
 596              (fabsf(local[1]) <= 1.0f) &&
 597              (fabsf(local[2]) <= 1.0f) )
 598          {
 599             in_volume = 1;
 600             vg_line_boxf_transformed( volume->to_world, cube, 0xff00ff00 );
 601
 602             if( !world_global.in_volume ){
 603                ent_call basecall;
 604                basecall.ent.index = idx;
 605                basecall.ent.type = k_ent_volume;
 606                basecall.function = k_ent_function_trigger;
 607                basecall.data = NULL;
 608
 609                entity_call( world, &basecall );
 610             }
 611          }
 612          else
 613             vg_line_boxf_transformed( volume->to_world, cube, 0xff0000ff );
 614       }
 615       else if( volume->type == k_volume_subtype_particle ){
 616          vg_line_boxf_transformed( volume->to_world, cube, 0xff00c0ff );
 617
 618          for( int j=0; j<random_ticks; j++ ){
 619             ent_call basecall;
 620             basecall.ent.index = idx;
 621             basecall.ent.type = k_ent_volume;
 622             basecall.function = k_ent_function_trigger;
 623             basecall.data = NULL;
 624
 625             entity_call( world, &basecall );
 626          }
 627       }
 628    }
 629    world_global.in_volume = in_volume;
 630
 631 #if 0
 632    if( k_debug_light_indices )
 633    {
 634       for( int i=0; i<world->light_count; i++ ){
 635          struct world_light *light = &world->lights[i];
 636          struct classtype_world_light *inf = light->inf;
 637
 638          u32 colour = 0xff000000;
 639          u8 r = inf->colour[0] * 255.0f,
 640             g = inf->colour[1] * 255.0f,
 641             b = inf->colour[2] * 255.0f;
 642
 643          colour |= r;
 644          colour |= g << 8;
 645          colour |= b << 16;
 646
 647          vg_line_pt3( light->node->co, 0.25f, colour );
 648       }
 649    }
 650
 651 #endif
 652
 653 #if 0
 654
 655    /* process soundscape transactions */
 656    audio_lock();
 657    for( int i=0; i<world->soundscape_count; i++ )
 658    {
 659       struct soundscape *s = &world->soundscapes[i];
 660       s->usage_count = 0;
 661
 662       for( int j=0; j<s->max_instances; j++ )
 663       {
 664          if( s->channels[j] )
 665          {
 666             if( audio_channel_finished(s->channels[j]) )
 667                s->channels[j] = audio_relinquish_channel( s->channels[j] );
 668             else
 669                s->usage_count ++;
 670          }
 671       }
 672    }
 673    audio_unlock();
 674 #endif
 675 }
 676
 677 /*
 678  * -----------------------------------------------------------------------------
 679  *                              API implementation
 680  * -----------------------------------------------------------------------------
 681  */
 682
 683 VG_STATIC void ray_world_get_tri( world_instance *world,
 684                                   ray_hit *hit, v3f tri[3] )
 685 {
 686    for( int i=0; i<3; i++ )
 687       v3_copy( world->scene_geo->arrvertices[ hit->tri[i] ].co, tri[i] );
 688 }
 689
 690 VG_STATIC int ray_world( world_instance *world,
 691                          v3f pos, v3f dir, ray_hit *hit )
 692 {
 693    return scene_raycast( world->scene_geo, world->geo_bh, pos, dir, hit );
 694 }
 695
 696 /*
 697  * Cast a sphere from a to b and see what time it hits
 698  */
 699 VG_STATIC int spherecast_world( world_instance *world,
 700                                 v3f pa, v3f pb, float r, float *t, v3f n )
 701 {
 702    bh_iter it;
 703    bh_iter_init( 0, &it );
 704
 705    boxf region;
 706    box_init_inf( region );
 707    box_addpt( region, pa );
 708    box_addpt( region, pb );
 709
 710    v3_add( (v3f){ r, r, r}, region[1], region[1] );
 711    v3_add( (v3f){-r,-r,-r}, region[0], region[0] );
 712
 713    v3f dir;
 714    v3_sub( pb, pa, dir );
 715
 716    v3f dir_inv;
 717    dir_inv[0] = 1.0f/dir[0];
 718    dir_inv[1] = 1.0f/dir[1];
 719    dir_inv[2] = 1.0f/dir[2];
 720
 721    int hit = -1;
 722    float min_t = 1.0f;
 723
 724    int idx;
 725    while( bh_next( world->geo_bh, &it, region, &idx ) ){
 726       u32 *ptri = &world->scene_geo->arrindices[ idx*3 ];
 727       v3f tri[3];
 728
 729       boxf box;
 730       box_init_inf( box );
 731
 732       for( int j=0; j<3; j++ ){
 733          v3_copy( world->scene_geo->arrvertices[ptri[j]].co, tri[j] );
 734          box_addpt( box, tri[j] );
 735       }
 736
 737       v3_add( (v3f){ r, r, r}, box[1], box[1] );
 738       v3_add( (v3f){-r,-r,-r}, box[0], box[0] );
 739
 740       if( !ray_aabb1( box, pa, dir_inv, 1.0f ) )
 741          continue;
 742
 743       float t;
 744       v3f n1;
 745       if( spherecast_triangle( tri, pa, dir, r, &t, n1 ) ){
 746          if( t < min_t ){
 747             min_t = t;
 748             hit = idx;
 749             v3_copy( n1, n );
 750          }
 751       }
 752    }
 753
 754    *t = min_t;
 755    return hit;
 756 }
 757
 758 VG_STATIC
 759 struct world_surface *world_tri_index_surface( world_instance *world,
 760                                                  u32 index )
 761 {
 762    for( int i=1; i<world->surface_count; i++ ){
 763       struct world_surface *surf = &world->surfaces[i];
 764
 765       if( (index >= surf->sm_geo.vertex_start) &&
 766           (index  < surf->sm_geo.vertex_start+surf->sm_geo.vertex_count ) )
 767       {
 768          return surf;
 769       }
 770    }
 771
 772    return &world->surfaces[0];
 773 }
 774
 775 VG_STATIC struct world_surface *world_contact_surface( world_instance *world,
 776                                                          rb_ct *ct )
 777 {
 778    return world_tri_index_surface( world, ct->element_id );
 779 }
 780
 781 VG_STATIC struct world_surface *ray_hit_surface( world_instance *world,
 782                                                  ray_hit *hit )
 783 {
 784    return world_tri_index_surface( world, hit->tri[0] );
 785 }
 786
 787 #endif /* WORLD_H */