X-Git-Url: https://harrygodden.com/git/?p=vg.git;a=blobdiff_plain;f=vg_bvh.h;fp=vg_bvh.h;h=37b100aa7c689394e1c834161162dfbe746a071d;hp=85790c5d58b310f35d2a319036891123cb37706f;hb=3b14f3dcd5bf9dd3c85144f2123d667bfa4bb63f;hpb=fce86711735b15bff37de0f70716808410fcf269

diff --git a/vg_bvh.h b/vg_bvh.h
index 85790c5..37b100a 100644
--- a/vg_bvh.h
+++ b/vg_bvh.h
@@ -47,6 +47,16 @@ struct bh_tree{
    nodes[];
 };
 
+/*
+ * TODO: This might get ugly, but it would make sense to do codegen here
+ *
+ *       eg.. #define BH_SYSTEM( FN_EXPAND, FN_CENTROID, FN_CLOSEST ... )
+ *
+ *       which macros out variants of the functions so we can give the compier
+ *       a more solid thing to work with without function pointers inside 
+ *       hot loops.
+ */
+
 struct bh_system{
    void  (*expand_bound)( void *user, boxf bound, u32 item_index );
    float (*item_centroid)( void *user, u32 item_index, int axis );
@@ -64,174 +74,19 @@ struct bh_system{
    int   (*cast_ray)( void *user, u32 index, v3f co, v3f dir, ray_hit *hit );
 };
 
-#define BVH_FIXED_MODE
-#ifdef BVH_FIXED_MODE
-static f32 shape_bvh_centroid( void *user, u32 item_index, int axis );
-static void shape_bvh_swap( void *user, u32 ia, u32 ib );
-static void shape_bvh_expand_bound( void *user, boxf bound, u32 item_index );
-#endif
-
-static void bh_update_bounds( bh_tree *bh, u32 inode ){
-   bh_node *node = &bh->nodes[ inode ];
-
-   box_init_inf( node->bbx );
-   for( u32 i=0; i<node->count; i++ ){
-      u32 idx = node->start+i;
-#ifdef BVH_FIXED_MODE
-      shape_bvh_expand_bound( bh->user, node->bbx, idx );
-#else
-      bh->system->expand_bound( bh->user, node->bbx, idx );
-#endif
-   }
-}
-
-static void bh_subdivide( bh_tree *bh, u32 inode ){
-   bh_node *node = &bh->nodes[ inode ];
-
-   if( node->count <= bh->max_per_leaf )
-      return;
-
-   v3f extent;
-   v3_sub( node->bbx[1], node->bbx[0], extent );
-
-   int axis = 0;
-   if( extent[1] > extent[0] ) axis = 1;
-   if( extent[2] > extent[axis] ) axis = 2;
-
-   float split = node->bbx[0][axis] + extent[axis]*0.5f;
-   float avg = 0.0;
-   for( u32 t=0; t<node->count; t++ ){
-      u32 idx = node->start+t;
-#ifdef BVH_FIXED_MODE
-      avg += shape_bvh_centroid( bh->user, idx, axis );
-#else
-      avg += bh->system->item_centroid( bh->user, idx, axis );
-#endif
-   }
-   avg /= (float)node->count;
-   split = avg;
-
-
-   i32 i = node->start,
-       j = i + node->count-1;
-   
-   while( i <= j ){
-#ifdef BVH_FIXED_MODE
-      f32 centroid = shape_bvh_centroid( bh->user, i, axis );
-#else
-      f32 centroid = bh->system->item_centroid( bh->user, i, axis );
-#endif
-
-      if( centroid < split )
-         i ++;
-      else{
-#ifdef BVH_FIXED_MODE
-         shape_bvh_swap( bh->user, i, j );
-#else
-         bh->system->item_swap( bh->user, i, j );
-#endif
-         j --;
-      }
-   }
-
-   u32 left_count = i - node->start;
-   if( left_count == 0 || left_count == node->count ) return;
-
-   u32 il = bh->node_count ++,
-       ir = bh->node_count ++;
-
-   bh_node *lnode = &bh->nodes[il],
-           *rnode = &bh->nodes[ir];
-
-   lnode->start = node->start;
-   lnode->count = left_count;
-   rnode->start = i;
-   rnode->count = node->count - left_count;
-
-   node->il = il;
-   node->ir = ir;
-   node->count = 0;
-
-   bh_update_bounds( bh, il );
-   bh_update_bounds( bh, ir );
-   bh_subdivide( bh, il );
-   bh_subdivide( bh, ir );
-}
-
-static void bh_rebuild( bh_tree *bh, u32 item_count ){
-   bh_node *root = &bh->nodes[0];
-   bh->node_count = 1;
-   
-   root->il = 0;
-   root->ir = 0;
-   root->count = item_count;
-   root->start = 0;
-
-   bh_update_bounds( bh, 0 );
-
-   if( item_count > 2 )
-      bh_subdivide( bh, 0 );
-}
-
-static bh_tree *bh_create( void *lin_alloc, bh_system *system, 
-                              void *user, u32 item_count, u32 max_per_leaf ){
-   assert( max_per_leaf > 0 );
+void bh_update_bounds( bh_tree *bh, u32 inode );
+void bh_subdivide( bh_tree *bh, u32 inode );
+void bh_rebuild( bh_tree *bh, u32 item_count );
+bh_tree *bh_create( void *lin_alloc, bh_system *system, 
+                    void *user, u32 item_count, u32 max_per_leaf );
 
-   u32 alloc_count = VG_MAX( 1, item_count );
 
-   u32 totsize = sizeof(bh_tree) + sizeof(bh_node)*(alloc_count*2-1);
-   bh_tree *bh = lin_alloc? vg_linear_alloc( lin_alloc, vg_align8(totsize) ):
-                            malloc( totsize );
-   bh->system = system;
-   bh->user = user;
-   bh->max_per_leaf = max_per_leaf;
-   bh_rebuild( bh, item_count );
-
-   if( lin_alloc ){
-      totsize = vg_align8(sizeof(bh_tree) + sizeof(bh_node) * bh->node_count);
-      bh = vg_linear_resize( lin_alloc, bh, totsize );
-   }
-
-   vg_success( "BVH done, size: %u/%u\n", bh->node_count, (alloc_count*2-1) );
-   return bh;
-}
-
-/*
- * Draw items in this leaf node.
- * *item_debug() must be set!
- */
-static void bh_debug_leaf( bh_tree *bh, bh_node *node ){
-   vg_line_boxf( node->bbx, 0xff00ff00 );
-
-   if( bh->system->item_debug ){
-      for( u32 i=0; i<node->count; i++ ){
-         u32 idx = node->start+i;
-         bh->system->item_debug( bh->user, idx );
-      }
-   }
-}
+void bh_debug_leaf( bh_tree *bh, bh_node *node );
 
 /*
  * Trace the bh tree all the way down to the leaf nodes where pos is inside
  */
-static void bh_debug_trace( bh_tree *bh, u32 inode, v3f pos, u32 colour ){
-   bh_node *node = &bh->nodes[ inode ];
-
-   if( (pos[0] >= node->bbx[0][0] && pos[0] <= node->bbx[1][0]) &&
-       (pos[2] >= node->bbx[0][2] && pos[2] <= node->bbx[1][2]) )
-   {
-      if( !node->count ){
-         vg_line_boxf( node->bbx, colour );
-
-         bh_debug_trace( bh, node->il, pos, colour );
-         bh_debug_trace( bh, node->ir, pos, colour );
-      }
-      else{
-         if( bh->system->item_debug )
-            bh_debug_leaf( bh, node );
-      }
-   }
-}
+void bh_debug_trace( bh_tree *bh, u32 inode, v3f pos, u32 colour );
 
 typedef struct bh_iter bh_iter;
 struct bh_iter{
@@ -269,147 +124,9 @@ struct bh_iter{
    i32 depth, i;
 };
 
-static void bh_iter_init_generic( i32 root, bh_iter *it ){
-   it->stack[0].id = root;
-   it->stack[0].depth = 0;
-   it->depth = 0;
-   it->i = 0;
-}
-
-static void bh_iter_init_box( i32 root, bh_iter *it, boxf box ){
-   bh_iter_init_generic( root, it );
-   it->query = k_bh_query_box;
-
-   box_copy( box, it->box.box );
-}
-
-static void bh_iter_init_ray( i32 root, bh_iter *it, v3f co, 
-                                 v3f dir, f32 max_dist ){
-   bh_iter_init_generic( root, it );
-   it->query = k_bh_query_ray;
-   
-   v3_div( (v3f){1.0f,1.0f,1.0f}, dir, it->ray.inv_dir );
-   v3_copy( co, it->ray.co );
-   it->ray.max_dist = max_dist;
-}
-
-static void bh_iter_init_range( i32 root, bh_iter *it, v3f co, f32 range ){
-   bh_iter_init_generic( root, it );
-   it->query = k_bh_query_range;
-
-   v3_copy( co, it->range.co );
-   it->range.dist_sqr = range*range;
-}
-
-/* NOTE: does not compute anything beyond the leaf level. element level tests
- *       should be implemented by the users code.
- *
- *       this is like a 'broad phase only' deal.
- */
-static i32 bh_next( bh_tree *bh, bh_iter *it, i32 *em ){
-   while( it->depth >= 0 ){
-      bh_node *inode = &bh->nodes[ it->stack[it->depth].id ];
-      
-      /* Only process overlapping nodes */
-      i32 q = 0;
-
-      if( it->i ) /* already checked */
-         q = 1;
-      else{
-         if( it->query == k_bh_query_box )
-            q = box_overlap( inode->bbx, it->box.box );
-         else if( it->query == k_bh_query_ray )
-            q = ray_aabb1( inode->bbx, it->ray.co, 
-                           it->ray.inv_dir, it->ray.max_dist );
-         else {
-            v3f nearest;
-            closest_point_aabb( it->range.co, inode->bbx, nearest );
-
-            if( v3_dist2( nearest, it->range.co ) <= it->range.dist_sqr )
-               q = 1;
-         }
-      }
-
-      if( !q ){
-         it->depth --;
-         continue;
-      }
-
-      if( inode->count ){
-         if( it->i < inode->count ){
-            *em = inode->start+it->i;
-            it->i ++;
-            return 1;
-         }
-         else{
-            it->depth --;
-            it->i = 0;
-         }
-      }
-      else{
-         if( it->depth+1 >= vg_list_size(it->stack) ){
-            vg_error( "Maximum stack reached!\n" );
-            return 0;
-         }
-
-         it->stack[it->depth  ].id = inode->il;
-         it->stack[it->depth+1].id = inode->ir;
-         it->depth ++;
-         it->i = 0;
-      }
-   }
-
-   return 0;
-}
-
-static int bh_closest_point( bh_tree *bh, v3f pos, 
-                                v3f closest, float max_dist )
-{
-   if( bh->node_count < 2 )
-      return -1;
-
-   max_dist = max_dist*max_dist;
-
-   int queue[ 128 ],
-       depth = 0,
-       best_item = -1;
-
-   queue[0] = 0;
-
-   while( depth >= 0 ){
-      bh_node *inode = &bh->nodes[ queue[depth] ];
-
-      v3f p1;
-      closest_point_aabb( pos, inode->bbx, p1 );
-
-      /* branch into node if its closer than current best */
-      float node_dist = v3_dist2( pos, p1 );
-      if( node_dist < max_dist ){
-         if( inode->count ){
-            for( int i=0; i<inode->count; i++ ){
-               v3f p2;
-               bh->system->item_closest( bh->user, inode->start+i, pos, p2 );
-
-               float item_dist = v3_dist2( pos, p2 );
-               if( item_dist < max_dist ){
-                  max_dist = item_dist;
-                  v3_copy( p2, closest );
-                  best_item = inode->start+i;
-               }
-            }
-
-            depth --;
-         }
-         else{
-            queue[depth] = inode->il;
-            queue[depth+1] = inode->ir;
-
-            depth ++;
-         }
-      }
-      else
-         depth --;
-   }
-
-   return best_item;
-}
+void bh_iter_init_generic( i32 root, bh_iter *it );
+void bh_iter_init_box( i32 root, bh_iter *it, boxf box );
+void bh_iter_init_ray( i32 root, bh_iter *it, v3f co, v3f dir, f32 max_dist );
+void bh_iter_init_range( i32 root, bh_iter *it, v3f co, f32 range );
+i32 bh_next( bh_tree *bh, bh_iter *it, i32 *em );
+int bh_closest_point( bh_tree *bh, v3f pos, v3f closest, float max_dist );