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
  23 #include "shaders/scene_standard.h"
  24 #include "shaders/scene_standard_alphatest.h"
  25 #include "shaders/scene_vertex_blend.h"
  26 #include "shaders/scene_terrain.h"
  27 #include "shaders/scene_depth.h"
  28 #include "shaders/scene_position.h"
  29
  30 #include "shaders/model_sky.h"
  31
  32 enum { k_max_ui_segments = 8 };
  33
  34 enum { k_max_ui_elements = k_max_ui_segments };
  35 enum { k_max_element_verts = 10 };
  36 enum { k_max_element_indices = 20 };
  37
  38 enum { k_route_ui_max_verts = k_max_ui_elements*k_max_element_verts };
  39 enum { k_route_ui_max_indices = k_max_ui_elements*k_max_element_indices };
  40
  41 enum logic_type
  42 {
  43    k_logic_type_relay         = 1,
  44    k_logic_type_chance        = 2,
  45    k_logic_type_achievement   = 3
  46 };
  47
  48 enum geo_type
  49 {
  50    k_geo_type_solid = 0,
  51    k_geo_type_nonsolid = 1,
  52    k_geo_type_water = 2
  53 };
  54
  55 static const float k_light_cube_size = 8.0f;
  56
  57 struct world_instance
  58 {
  59    /* This is a small flag we use to changelevel.
  60     * It will not be cleared until all sounds stop playing
  61     */
  62
  63    /* Fixed items
  64     * -------------------------------------------------------
  65     */
  66
  67    char  world_name[ 64 ];
  68
  69    struct
  70    {
  71       boxf depthbounds;
  72       int depth_computed;
  73
  74       float height;
  75       int enabled;
  76       v4f plane;
  77    }
  78    water;
  79
  80    /* STD140 */
  81    struct ub_world_lighting
  82    {
  83       v4f g_cube_min,
  84           g_cube_inv_range;
  85
  86       v4f g_water_plane,
  87           g_depth_bounds;
  88
  89       v4f g_daysky_colour;
  90       v4f g_nightsky_colour;
  91       v4f g_sunset_colour;
  92       v4f g_ambient_colour;
  93       v4f g_sunset_ambient;
  94       v4f g_sun_colour;
  95       v4f g_sun_dir;
  96
  97       float g_water_fog;
  98       float g_time;
  99       float g_realtime;
 100       float g_shadow_length;
 101       float g_shadow_spread;
 102
 103       float g_time_of_day;
 104       float g_day_phase;
 105       float g_sunset_phase;
 106
 107       int g_light_preview;
 108       int g_shadow_samples;
 109
 110       int g_debug_indices;
 111       int g_debug_complexity;
 112    }
 113    ub_lighting;
 114    GLuint ubo_lighting;
 115    int    ubo_bind_point;
 116
 117    GLuint tbo_light_entities,
 118           tex_light_entities,
 119           tex_light_cubes;
 120
 121    v3i light_cubes;
 122
 123    struct framebuffer heightmap;
 124
 125    /*
 126     * Dynamically allocated when world_load is called.
 127     *
 128     *                  the following arrays index somewhere into this linear
 129     *                  allocator
 130     *
 131     * (world_gen.h)
 132     * --------------------------------------------------------------------------
 133     */
 134    /*
 135     * Main world .mdl
 136     */
 137    mdl_context meta;
 138
 139    GLuint *textures;
 140    u32 texture_count;
 141
 142    struct world_surface
 143    {
 144       mdl_material info;
 145       mdl_submesh sm_geo,
 146                   sm_no_collide;
 147    }
 148    * surfaces;
 149    u32 surface_count;
 150
 151    mdl_array_ptr ent_spawn,
 152                  ent_gate,
 153                  ent_light,
 154                  ent_route_node,
 155                  ent_path_index,
 156                  ent_checkpoint,
 157                  ent_route,
 158                  ent_water,
 159
 160                  ent_audio_clip,
 161                  ent_audio,
 162                  ent_volume;
 163
 164    ent_gate *rendering_gate;
 165
 166 #if 0
 167    /*
 168     * Named safe places to respawn
 169     */
 170    struct respawn_point
 171    {
 172       v3f co;
 173       v4f q;
 174       const char *name;
 175    }
 176    * spawns;
 177    u32 spawn_count;
 178
 179    /*
 180     * Audio player entities
 181     */
 182    struct world_audio_thing
 183    {
 184       v3f pos;
 185       float volume, range;
 186       u32 flags;
 187       audio_clip temp_embedded_clip;
 188    }
 189    * audio_things;
 190    u32 audio_things_count;
 191
 192    struct soundscape
 193    {
 194       /* locking */
 195       audio_channel *channels[4];
 196
 197       /* accessable without locking */
 198       v3f spawn_position;
 199
 200       u32 usage_count;
 201       u32 max_instances;
 202       u32 allow_transitions;
 203       float transition_duration;
 204       const char *label;
 205    }
 206    * soundscapes;
 207    u32 soundscape_count;
 208
 209    /*
 210     * Box volume entities
 211     */
 212    struct world_volume
 213    {
 214       m4x3f transform, inv_transform;
 215       mdl_node *node;
 216    }
 217    * volumes;
 218    u32 volume_count;
 219
 220    /*
 221     * Lights
 222     */
 223    struct world_light
 224    {
 225       mdl_node *node;
 226       struct classtype_world_light *inf;
 227       m4x3f inverse_world;
 228       v2f angle_sin_cos;
 229    }
 230    * lights;
 231    u32 light_count;
 232
 233    /*
 234     * Routes (world_routes.h)
 235     * --------------------------------------------------------------------------
 236     */
 237
 238    struct route_node
 239    {
 240       v3f co, right, up, h;
 241       u32 next[2];
 242
 243       u32 special_type, special_id, current_refs, ref_count;
 244       u32 route_ids[4];    /* Gates can be linked into up to four routes */
 245    }
 246    *nodes;
 247    u32 node_count;
 248
 249    struct route
 250    {
 251       u32 track_id;
 252       v4f colour;
 253
 254       u32 start;
 255       mdl_submesh sm;
 256
 257       int active;
 258       float factive;
 259
 260       double best_lap, latest_pass; /* Session */
 261
 262       m4x3f scoreboard_transform;
 263    }
 264    *routes;
 265    u32 route_count;
 266
 267    struct route_gate
 268    {
 269       struct teleport_gate
 270       {
 271          v3f co[2];
 272          v4f q[2];
 273          v2f dims;
 274
 275          m4x3f to_world, transport;
 276       }
 277       gate;
 278
 279       u32 node_id;
 280
 281       struct route_timing
 282       {
 283          u32 version; /* Incremented on every teleport */
 284          double time;
 285       }
 286       timing;
 287    }
 288    *gates;
 289    u32 gate_count;
 290
 291    struct nonlocal_gate
 292    {
 293       struct teleport_gate gate;
 294       mdl_node *node;
 295
 296       u32 target_map_index, working;
 297    }
 298    *nonlocal_gates;
 299    u32 nonlocalgate_count;
 300
 301    struct route_collector
 302    {
 303       struct route_timing timing;
 304    }
 305    *collectors;
 306    u32 collector_count;
 307 #endif
 308
 309
 310    /* logic
 311     * ----------------------------------------------------
 312     */
 313
 314    /* world geometry */
 315    scene *scene_geo,
 316          *scene_no_collide,
 317          *scene_lines;
 318
 319    /* spacial mappings */
 320    bh_tree *audio_bh,
 321            *volume_bh,
 322            *geo_bh;
 323
 324    /* graphics */
 325    glmesh mesh_route_lines;
 326    glmesh mesh_geo,
 327           mesh_no_collide,
 328           mesh_water;
 329
 330    rigidbody rb_geo; /* todo.. ... */
 331 };
 332
 333 VG_STATIC struct world_global
 334 {
 335    /*
 336     * Allocated as system memory
 337     * --------------------------------------------------------------------------
 338     */
 339    void *generic_heap;
 340
 341    /* rendering */
 342    glmesh skydome;
 343    glmesh mesh_gate;
 344    mdl_submesh sm_gate_surface,
 345                sm_gate_marker[4];
 346
 347    double sky_time, sky_rate, sky_target_rate;
 348
 349    u32 current_run_version;
 350    double time, rewind_from, rewind_to, last_use;
 351
 352    /* water rendering */
 353    struct
 354    {
 355       struct framebuffer fbreflect, fbdepth;
 356    }
 357    water;
 358
 359    /* split flap display */
 360    struct
 361    {
 362       glmesh mesh_base, mesh_display;
 363       mdl_submesh sm_base;
 364       u32 active_route_board;
 365
 366       u32 w, h;
 367       float *buffer;
 368    }
 369    sfd;
 370
 371    v3f render_gate_pos;
 372    int in_volume;
 373
 374    int switching_to_new_world;
 375
 376    world_instance worlds[4];
 377    u32            world_count;
 378    u32            active_world;
 379 }
 380 world_global;
 381
 382 VG_STATIC world_instance *get_active_world( void )
 383 {
 384    return &world_global.worlds[ world_global.active_world ];
 385 }
 386
 387 /*
 388  * API
 389  */
 390
 391 VG_STATIC
 392 int ray_hit_is_ramp( world_instance *world, ray_hit *hit );
 393
 394 VG_STATIC
 395 struct world_surface *ray_hit_surface( world_instance *world, ray_hit *hit );
 396
 397 VG_STATIC
 398 void ray_world_get_tri( world_instance *world, ray_hit *hit, v3f tri[3] );
 399
 400 VG_STATIC
 401 int ray_world( world_instance *world, v3f pos, v3f dir, ray_hit *hit );
 402
 403 /*
 404  * Submodules
 405  */
 406
 407 #include "world_routes.h"
 408 #include "world_sfd.h"
 409 #include "world_render.h"
 410 #include "world_water.h"
 411 #include "world_volumes.h"
 412 #include "world_gen.h"
 413 #include "world_gate.h"
 414
 415 /*
 416  * -----------------------------------------------------------------------------
 417  *                                    Events
 418  * -----------------------------------------------------------------------------
 419  */
 420
 421 VG_STATIC int world_stop_sound( int argc, const char *argv[] )
 422 {
 423    world_instance *world = get_active_world();
 424    return 0;
 425 }
 426
 427 VG_STATIC void world_init(void)
 428 {
 429    world_global.sky_rate = 1.0;
 430    world_global.sky_target_rate = 1.0;
 431
 432    shader_scene_standard_register();
 433    shader_scene_standard_alphatest_register();
 434    shader_scene_vertex_blend_register();
 435    shader_scene_terrain_register();
 436    shader_scene_depth_register();
 437    shader_scene_position_register();
 438
 439    shader_model_sky_register();
 440
 441    vg_info( "Loading world resources\n" );
 442
 443    vg_linear_clear( vg_mem.scratch );
 444
 445    mdl_context msky;
 446    mdl_open( &msky, "models/rs_skydome.mdl", vg_mem.scratch );
 447    mdl_load_metadata_block( &msky, vg_mem.scratch );
 448    mdl_load_mesh_block( &msky, vg_mem.scratch );
 449    mdl_close( &msky );
 450
 451    vg_acquire_thread_sync();
 452    {
 453       mdl_unpack_glmesh( &msky, &world_global.skydome );
 454    }
 455    vg_release_thread_sync();
 456
 457    /* Other systems */
 458    vg_info( "Loading other world systems\n" );
 459
 460    vg_loader_step( world_render_init, NULL );
 461    vg_loader_step( world_sfd_init, NULL );
 462    vg_loader_step( world_water_init, NULL );
 463    vg_loader_step( world_gates_init, NULL );
 464    vg_loader_step( world_routes_init, NULL );
 465
 466    /* Allocate dynamic world memory arena */
 467    u32 max_size = 76*1024*1024;
 468    world_global.generic_heap = vg_create_linear_allocator( vg_mem.rtmemory,
 469                                                            max_size,
 470                                                            VG_MEMORY_SYSTEM );
 471 }
 472
 473 typedef struct ent_call ent_call;
 474 struct ent_call{
 475    ent_index ent;
 476    u32 function;
 477    void *data;
 478 };
 479
 480 VG_STATIC void entity_call( world_instance *world, ent_call *call );
 481
 482 VG_STATIC void ent_volume_call( world_instance *world, ent_call *call )
 483 {
 484    ent_volume *volume = mdl_arritm( &world->ent_volume, call->ent.index );
 485    if( !volume->target.type ) return;
 486
 487    if( call->function == k_ent_function_trigger ){
 488       call->ent = volume->target;
 489
 490       if( volume->type == k_volume_subtype_particle ){
 491          v3f co;
 492          co[0] = vg_randf()*2.0f-1.0f;
 493          co[1] = vg_randf()*2.0f-1.0f;
 494          co[2] = vg_randf()*2.0f-1.0f;
 495          m4x3_mulv( volume->to_world, co, co );
 496
 497          call->function = k_ent_function_particle_spawn;
 498          call->data = co;
 499
 500          entity_call( world, call );
 501       }
 502       else if( volume->type == k_volume_subtype_trigger ){
 503          /* TODO */
 504       }
 505    }
 506 }
 507
 508 VG_STATIC void ent_audio_call( world_instance *world, ent_call *call )
 509 {
 510    ent_audio *audio = mdl_arritm( &world->ent_audio, call->ent.index );
 511
 512    if( call->function == k_ent_function_particle_spawn ){
 513       float chance = vg_randf()*100.0f,
 514             bar = 0.0f;
 515
 516       for( u32 i=0; i<audio->clip_count; i++ ){
 517          ent_audio_clip *clip = mdl_arritm( &world->ent_audio_clip,
 518                                              audio->clip_start+i );
 519
 520          bar += clip->probability;
 521
 522          if( chance < bar ){
 523             float *pos = call->data;
 524
 525             audio_lock();
 526             audio_oneshot_3d( &clip->clip, pos,
 527                               audio->transform.s[0],
 528                               audio->volume );
 529             audio_unlock();
 530             break;
 531          }
 532       }
 533    }
 534 }
 535
 536 VG_STATIC void entity_call( world_instance *world, ent_call *call )
 537 {
 538    if( call->ent.type == k_ent_volume ){
 539       ent_volume_call( world, call );
 540    } else if( call->ent.type == k_ent_audio ){
 541       ent_audio_call( world, call );
 542    }
 543 }
 544
 545 VG_STATIC void world_update( world_instance *world, v3f pos )
 546 {
 547    /* TEMP!!!!!! */
 548    static double g_time = 0.0;
 549    g_time += vg.time_delta * (1.0/(k_day_length*60.0));
 550
 551
 552    struct ub_world_lighting *state = &world->ub_lighting;
 553
 554    state->g_time = g_time;
 555    state->g_realtime = vg.time;
 556    state->g_debug_indices = k_debug_light_indices;
 557    state->g_light_preview = k_light_preview;
 558    state->g_debug_complexity = k_debug_light_complexity;
 559
 560    state->g_time_of_day = vg_fractf( g_time );
 561    state->g_day_phase   = cosf( state->g_time_of_day * VG_PIf * 2.0f );
 562    state->g_sunset_phase= cosf( state->g_time_of_day * VG_PIf * 4.0f + VG_PIf );
 563
 564    state->g_day_phase    =       state->g_day_phase    * 0.5f + 0.5f;
 565    state->g_sunset_phase = powf( state->g_sunset_phase * 0.5f + 0.5f, 6.0f );
 566
 567    float a = state->g_time_of_day * VG_PIf * 2.0f;
 568    state->g_sun_dir[0] = sinf( a );
 569    state->g_sun_dir[1] = cosf( a );
 570    state->g_sun_dir[2] = 0.2f;
 571    v3_normalize( state->g_sun_dir );
 572
 573
 574
 575    glBindBuffer( GL_UNIFORM_BUFFER, world->ubo_lighting );
 576    glBufferSubData( GL_UNIFORM_BUFFER, 0,
 577                     sizeof(struct ub_world_lighting), &world->ub_lighting );
 578    /* TEMP!!!!!! */
 579
 580    world_global.sky_time += world_global.sky_rate * vg.time_delta;
 581    world_global.sky_rate = vg_lerp( world_global.sky_rate,
 582                                     world_global.sky_target_rate,
 583                                     vg.time_delta * 5.0 );
 584
 585    world_routes_update( world );
 586    world_routes_debug( world );
 587
 588    /* ---- SFD ------------ */
 589
 590    if( mdl_arrcount( &world->ent_route ) ){
 591       u32 closest = 0;
 592       float min_dist = INFINITY;
 593
 594       for( u32 i=0; i<mdl_arrcount( &world->ent_route ); i++ ){
 595          ent_route *route = mdl_arritm( &world->ent_route, i );
 596          float dist = v3_dist2( route->board_transform[3], pos );
 597
 598          if( dist < min_dist ){
 599             min_dist = dist;
 600             closest = i;
 601          }
 602       }
 603
 604       if( (world_global.sfd.active_route_board != closest)
 605           || network_scores_updated )
 606       {
 607          network_scores_updated = 0;
 608          world_global.sfd.active_route_board = closest;
 609
 610          ent_route *route = mdl_arritm( &world->ent_route, closest );
 611          u32 id = route->official_track_id;
 612
 613          if( id != 0xffffffff ){
 614             struct netmsg_board *local_board =
 615                &scoreboard_client_data.boards[id];
 616
 617             for( int i=0; i<13; i++ ){
 618                sfd_encode( i, &local_board->data[27*i] );
 619             }
 620          }else{
 621             sfd_encode( 0, mdl_pstr( &world->meta, route->pstr_name ) );
 622             sfd_encode( 1, "No data" );
 623          }
 624       }
 625    }
 626    sfd_update();
 627
 628
 629
 630    static float random_accum = 0.0f;
 631    random_accum += vg.time_delta;
 632
 633    u32 random_ticks = 0;
 634
 635    while( random_accum > 0.1f ){
 636       random_accum -= 0.1f;
 637       random_ticks ++;
 638    }
 639
 640    float radius = 25.0f;
 641    boxf volume_proximity;
 642    v3_add( pos, (v3f){ radius, radius, radius }, volume_proximity[1] );
 643    v3_sub( pos, (v3f){ radius, radius, radius }, volume_proximity[0] );
 644
 645    bh_iter it;
 646    bh_iter_init( 0, &it );
 647    int idx;
 648
 649    int in_volume = 0;
 650
 651    while( bh_next( world->volume_bh, &it, volume_proximity, &idx ) ){
 652       ent_volume *volume = mdl_arritm( &world->ent_volume, idx );
 653
 654       boxf cube = {{-1.0f,-1.0f,-1.0f},{1.0f,1.0f,1.0f}};
 655
 656       if( volume->type == k_volume_subtype_trigger ){
 657          v3f local;
 658          m4x3_mulv( volume->to_local, pos, local );
 659          vg_line_boxf_transformed( volume->to_world, cube, 0xff00ff00 );
 660
 661          if( (fabsf(local[0]) <= 1.0f) &&
 662              (fabsf(local[1]) <= 1.0f) &&
 663              (fabsf(local[2]) <= 1.0f) )
 664          {
 665             in_volume = 1;
 666
 667             if( !world_global.in_volume ){
 668                ent_call basecall;
 669                basecall.ent.index = idx;
 670                basecall.ent.type = k_ent_volume;
 671                basecall.function = k_ent_function_trigger;
 672                basecall.data = NULL;
 673
 674                entity_call( world, &basecall );
 675             }
 676          }
 677       }
 678       else if( volume->type == k_volume_subtype_particle ){
 679          vg_line_boxf_transformed( volume->to_world, cube, 0xff00c0ff );
 680
 681          for( int j=0; j<random_ticks; j++ ){
 682             ent_call basecall;
 683             basecall.ent.index = idx;
 684             basecall.ent.type = k_ent_volume;
 685             basecall.function = k_ent_function_trigger;
 686             basecall.data = NULL;
 687
 688             entity_call( world, &basecall );
 689          }
 690       }
 691    }
 692    world_global.in_volume = in_volume;
 693
 694 #if 0
 695    if( k_debug_light_indices )
 696    {
 697       for( int i=0; i<world->light_count; i++ ){
 698          struct world_light *light = &world->lights[i];
 699          struct classtype_world_light *inf = light->inf;
 700
 701          u32 colour = 0xff000000;
 702          u8 r = inf->colour[0] * 255.0f,
 703             g = inf->colour[1] * 255.0f,
 704             b = inf->colour[2] * 255.0f;
 705
 706          colour |= r;
 707          colour |= g << 8;
 708          colour |= b << 16;
 709
 710          vg_line_pt3( light->node->co, 0.25f, colour );
 711       }
 712    }
 713
 714 #endif
 715
 716 #if 0
 717
 718    /* process soundscape transactions */
 719    audio_lock();
 720    for( int i=0; i<world->soundscape_count; i++ )
 721    {
 722       struct soundscape *s = &world->soundscapes[i];
 723       s->usage_count = 0;
 724
 725       for( int j=0; j<s->max_instances; j++ )
 726       {
 727          if( s->channels[j] )
 728          {
 729             if( audio_channel_finished(s->channels[j]) )
 730                s->channels[j] = audio_relinquish_channel( s->channels[j] );
 731             else
 732                s->usage_count ++;
 733          }
 734       }
 735    }
 736    audio_unlock();
 737 #endif
 738 }
 739
 740 /*
 741  * -----------------------------------------------------------------------------
 742  *                              API implementation
 743  * -----------------------------------------------------------------------------
 744  */
 745
 746 VG_STATIC void ray_world_get_tri( world_instance *world,
 747                                   ray_hit *hit, v3f tri[3] )
 748 {
 749    for( int i=0; i<3; i++ )
 750       v3_copy( world->scene_geo->arrvertices[ hit->tri[i] ].co, tri[i] );
 751 }
 752
 753 VG_STATIC int ray_world( world_instance *world,
 754                          v3f pos, v3f dir, ray_hit *hit )
 755 {
 756    return scene_raycast( world->scene_geo, world->geo_bh, pos, dir, hit );
 757 }
 758
 759 /*
 760  * Cast a sphere from a to b and see what time it hits
 761  */
 762 VG_STATIC int spherecast_world( world_instance *world,
 763                                 v3f pa, v3f pb, float r, float *t, v3f n )
 764 {
 765    bh_iter it;
 766    bh_iter_init( 0, &it );
 767
 768    boxf region;
 769    box_init_inf( region );
 770    box_addpt( region, pa );
 771    box_addpt( region, pb );
 772
 773    v3_add( (v3f){ r, r, r}, region[1], region[1] );
 774    v3_add( (v3f){-r,-r,-r}, region[0], region[0] );
 775
 776    v3f dir;
 777    v3_sub( pb, pa, dir );
 778
 779    v3f dir_inv;
 780    dir_inv[0] = 1.0f/dir[0];
 781    dir_inv[1] = 1.0f/dir[1];
 782    dir_inv[2] = 1.0f/dir[2];
 783
 784    int hit = -1;
 785    float min_t = 1.0f;
 786
 787    int idx;
 788    while( bh_next( world->geo_bh, &it, region, &idx ) ){
 789       u32 *ptri = &world->scene_geo->arrindices[ idx*3 ];
 790       v3f tri[3];
 791
 792       boxf box;
 793       box_init_inf( box );
 794
 795       for( int j=0; j<3; j++ ){
 796          v3_copy( world->scene_geo->arrvertices[ptri[j]].co, tri[j] );
 797          box_addpt( box, tri[j] );
 798       }
 799
 800       v3_add( (v3f){ r, r, r}, box[1], box[1] );
 801       v3_add( (v3f){-r,-r,-r}, box[0], box[0] );
 802
 803       if( !ray_aabb1( box, pa, dir_inv, 1.0f ) )
 804          continue;
 805
 806       float t;
 807       v3f n1;
 808       if( spherecast_triangle( tri, pa, dir, r, &t, n1 ) ){
 809          if( t < min_t ){
 810             min_t = t;
 811             hit = idx;
 812             v3_copy( n1, n );
 813          }
 814       }
 815    }
 816
 817    *t = min_t;
 818    return hit;
 819 }
 820
 821 VG_STATIC
 822 struct world_surface *world_tri_index_surface( world_instance *world,
 823                                                  u32 index )
 824 {
 825    for( int i=1; i<world->surface_count; i++ ){
 826       struct world_surface *surf = &world->surfaces[i];
 827
 828       if( (index >= surf->sm_geo.vertex_start) &&
 829           (index  < surf->sm_geo.vertex_start+surf->sm_geo.vertex_count ) )
 830       {
 831          return surf;
 832       }
 833    }
 834
 835    return &world->surfaces[0];
 836 }
 837
 838 VG_STATIC struct world_surface *world_contact_surface( world_instance *world,
 839                                                          rb_ct *ct )
 840 {
 841    return world_tri_index_surface( world, ct->element_id );
 842 }
 843
 844 VG_STATIC struct world_surface *ray_hit_surface( world_instance *world,
 845                                                  ray_hit *hit )
 846 {
 847    return world_tri_index_surface( world, hit->tri[0] );
 848 }
 849
 850 #endif /* WORLD_H */