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 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 static int ray_world( world_instance *world,
  15                          v3f pos, v3f dir, ray_hit *hit, u16 ignore )
  16 {
  17    return scene_raycast( &world->scene_geo, world->geo_bh, pos, dir, hit,
  18                          ignore );
  19 }
  20
  21 /*
  22  * Cast a sphere from a to b and see what time it hits
  23  */
  24 static int spherecast_world( world_instance *world,
  25                                 v3f pa, v3f pb, float r, float *t, v3f n,
  26                                 u16 ignore )
  27 {
  28    boxf region;
  29    box_init_inf( region );
  30    box_addpt( region, pa );
  31    box_addpt( region, pb );
  32
  33    v3_add( (v3f){ r, r, r}, region[1], region[1] );
  34    v3_add( (v3f){-r,-r,-r}, region[0], region[0] );
  35
  36    v3f dir;
  37    v3_sub( pb, pa, dir );
  38
  39    v3f dir_inv;
  40    dir_inv[0] = 1.0f/dir[0];
  41    dir_inv[1] = 1.0f/dir[1];
  42    dir_inv[2] = 1.0f/dir[2];
  43
  44    int hit = -1;
  45    float min_t = 1.0f;
  46
  47    bh_iter it;
  48    bh_iter_init_box( 0, &it, region );
  49    i32 idx;
  50    while( bh_next( world->geo_bh, &it, &idx ) ){
  51       u32 *ptri = &world->scene_geo.arrindices[ idx*3 ];
  52       if( world->scene_geo.arrvertices[ptri[0]].flags & ignore ) continue;
  53
  54       v3f tri[3];
  55       boxf box;
  56       box_init_inf( box );
  57       for( int j=0; j<3; j++ ){
  58          v3_copy( world->scene_geo.arrvertices[ptri[j]].co, tri[j] );
  59          box_addpt( box, tri[j] );
  60       }
  61
  62       v3_add( (v3f){ r, r, r}, box[1], box[1] );
  63       v3_add( (v3f){-r,-r,-r}, box[0], box[0] );
  64
  65       if( !ray_aabb1( box, pa, dir_inv, 1.0f ) )
  66          continue;
  67
  68       float t;
  69       v3f n1;
  70       if( spherecast_triangle( tri, pa, dir, r, &t, n1 ) ){
  71          if( t < min_t ){
  72             min_t = t;
  73             hit = idx;
  74             v3_copy( n1, n );
  75          }
  76       }
  77    }
  78
  79    *t = min_t;
  80    return hit;
  81 }
  82
  83 static
  84 struct world_surface *world_tri_index_surface( world_instance *world,
  85                                                  u32 index )
  86 {
  87    for( int i=1; i<world->surface_count; i++ ){
  88       struct world_surface *surf = &world->surfaces[i];
  89
  90       if( (index >= surf->sm_geo.vertex_start) &&
  91           (index  < surf->sm_geo.vertex_start+surf->sm_geo.vertex_count ) )
  92       {
  93          return surf;
  94       }
  95    }
  96
  97    return &world->surfaces[0];
  98 }
  99
 100 static struct world_surface *world_contact_surface( world_instance *world,
 101                                                          rb_ct *ct )
 102 {
 103    return world_tri_index_surface( world, ct->element_id );
 104 }
 105
 106 static struct world_surface *ray_hit_surface( world_instance *world,
 107                                                  ray_hit *hit )
 108 {
 109    return world_tri_index_surface( world, hit->tri[0] );
 110 }
 111
 112 #endif /* WORLD_PHYSICS_C */