world_physics.c

   1 #ifndef WORLD_PHYSICS_C
   2 #define WORLD_PHYSICS_C
   3
   4 #include "world.h"
   5 #include "world_physics.h"
   6
   7 VG_STATIC void ray_world_get_tri( world_instance *world,
   8                                   ray_hit *hit, v3f tri[3] )
   9 {
  10    for( int i=0; i<3; i++ )
  11       v3_copy( world->scene_geo.arrvertices[ hit->tri[i] ].co, tri[i] );
  12 }
  13
  14 VG_STATIC int ray_world( world_instance *world,
  15                          v3f pos, v3f dir, ray_hit *hit )
  16 {
  17    return scene_raycast( &world->scene_geo, world->geo_bh, pos, dir, hit );
  18 }
  19
  20 /*
  21  * Cast a sphere from a to b and see what time it hits
  22  */
  23 VG_STATIC int spherecast_world( world_instance *world,
  24                                 v3f pa, v3f pb, float r, float *t, v3f n )
  25 {
  26    boxf region;
  27    box_init_inf( region );
  28    box_addpt( region, pa );
  29    box_addpt( region, pb );
  30
  31    v3_add( (v3f){ r, r, r}, region[1], region[1] );
  32    v3_add( (v3f){-r,-r,-r}, region[0], region[0] );
  33
  34    v3f dir;
  35    v3_sub( pb, pa, dir );
  36
  37    v3f dir_inv;
  38    dir_inv[0] = 1.0f/dir[0];
  39    dir_inv[1] = 1.0f/dir[1];
  40    dir_inv[2] = 1.0f/dir[2];
  41
  42    int hit = -1;
  43    float min_t = 1.0f;
  44
  45    bh_iter it;
  46    bh_iter_init_box( 0, &it, region );
  47    i32 idx;
  48    while( bh_next( world->geo_bh, &it, &idx ) ){
  49       u32 *ptri = &world->scene_geo.arrindices[ idx*3 ];
  50       v3f tri[3];
  51
  52       boxf box;
  53       box_init_inf( box );
  54
  55       for( int j=0; j<3; j++ ){
  56          v3_copy( world->scene_geo.arrvertices[ptri[j]].co, tri[j] );
  57          box_addpt( box, tri[j] );
  58       }
  59
  60       v3_add( (v3f){ r, r, r}, box[1], box[1] );
  61       v3_add( (v3f){-r,-r,-r}, box[0], box[0] );
  62
  63       if( !ray_aabb1( box, pa, dir_inv, 1.0f ) )
  64          continue;
  65
  66       float t;
  67       v3f n1;
  68       if( spherecast_triangle( tri, pa, dir, r, &t, n1 ) ){
  69          if( t < min_t ){
  70             min_t = t;
  71             hit = idx;
  72             v3_copy( n1, n );
  73          }
  74       }
  75    }
  76
  77    *t = min_t;
  78    return hit;
  79 }
  80
  81 VG_STATIC
  82 struct world_surface *world_tri_index_surface( world_instance *world,
  83                                                  u32 index )
  84 {
  85    for( int i=1; i<world->surface_count; i++ ){
  86       struct world_surface *surf = &world->surfaces[i];
  87
  88       if( (index >= surf->sm_geo.vertex_start) &&
  89           (index  < surf->sm_geo.vertex_start+surf->sm_geo.vertex_count ) )
  90       {
  91          return surf;
  92       }
  93    }
  94
  95    return &world->surfaces[0];
  96 }
  97
  98 VG_STATIC struct world_surface *world_contact_surface( world_instance *world,
  99                                                          rb_ct *ct )
 100 {
 101    return world_tri_index_surface( world, ct->element_id );
 102 }
 103
 104 VG_STATIC struct world_surface *ray_hit_surface( world_instance *world,
 105                                                  ray_hit *hit )
 106 {
 107    return world_tri_index_surface( world, hit->tri[0] );
 108 }
 109
 110 #endif /* WORLD_PHYSICS_C */