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 );
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{
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 );
projects / vg.git / blobdiff