+/*
+ * Copyright (C) 2021-2022 Mt.ZERO Software, Harry Godden - All Rights Reserved
+ */
+
#ifndef BVH_H
#define BVH_H
#include "common.h"
* user: a pointer back the base of the data you are ordering
* system: the system we created above which will deal with the data
*
- * call bh_create( bh_tree *bh, u32 item_count, u32 item_size )
+ * call bh_create( bh_tree *bh, u32 item_count )
+ * VG_STATIC int bh_ray( bh_tree *bh, u32 inode, v3f co, v3f dir, ray_hit *hit )
+ * VG_STATIC int bh_select( bh_tree *bh, boxf box, u32 *buffer, int len )
*/
typedef struct bh_node bh_node;
typedef struct bh_tree bh_tree;
typedef struct bh_system bh_system;
-struct bh_node
-{
- boxf bbx;
-
- /* if il is 0, this is a leaf */
- u32 il, count;
- union{ u32 ir, start; };
-};
-
struct bh_tree
{
- bh_node *nodes;
u32 node_count;
bh_system *system;
void *user;
+ u32 max_per_leaf;
+
+ struct bh_node
+ {
+ boxf bbx;
+
+ /* if il is 0, this is a leaf */
+ int il, count;
+ union{ int ir, start; };
+ }
+ nodes[];
};
struct bh_system
{
void (*expand_bound)( void *user, boxf bound, u32 item_index );
float (*item_centroid)( void *user, u32 item_index, int axis );
+ void (*item_closest)( void *user, u32 item_index, v3f point, v3f closest );
void (*item_swap)( void *user, u32 ia, u32 ib );
- u32 item_size;
/*
* Optional:
*/
void (*item_debug)( void *user, u32 item_index );
- int (*cast_ray)( void *user, v3f co, v3f dir, ray_hit *hit );
+ int (*cast_ray)( void *user, u32 index, v3f co, v3f dir, ray_hit *hit );
};
-static void bh_update_bounds( bh_tree *bh, u32 inode )
+VG_STATIC void bh_update_bounds( bh_tree *bh, u32 inode )
{
bh_node *node = &bh->nodes[ inode ];
}
}
-static void bh_subdivide( bh_tree *bh, u32 inode )
+VG_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 );
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++ )
{
avg += bh->system->item_centroid( bh->user, idx, axis );
}
avg /= (float)node->count;
-
split = avg;
+
i32 i = node->start,
j = i + node->count-1;
node->ir = ir;
node->count = 0;
- /* TODO: Implement max depth, or stack */
bh_update_bounds( bh, il );
bh_update_bounds( bh, ir );
bh_subdivide( bh, il );
bh_subdivide( bh, ir );
}
-static void bh_create( bh_tree *bh, bh_system *sys, u32 item_count )
+VG_STATIC bh_tree *bh_create( void *lin_alloc, bh_system *system,
+ void *user, u32 item_count, u32 max_per_leaf )
{
- bh->system = sys;
- bh->nodes = malloc( sys->item_size * (item_count*2-1) );
+ assert( max_per_leaf > 0 );
+
+ u32 alloc_count = VG_MAX( 1, item_count );
+
+ u32 totsize = sizeof(bh_tree) + sizeof(bh_node)*(alloc_count*2-1);
+ bh_tree *bh = vg_linear_alloc( lin_alloc, vg_align8(totsize) );
+ bh->system = system;
+ bh->user = user;
+ bh->max_per_leaf = max_per_leaf;
bh_node *root = &bh->nodes[0];
bh->node_count = 1;
root->start = 0;
bh_update_bounds( bh, 0 );
- bh_subdivide( bh, 0 );
- bh->nodes = realloc( bh->nodes, sys->item_size * bh->node_count );
- vg_success( "BVH done, size: %u/%u\n", bh->node_count, (item_count*2-1) );
+ if( item_count > 2 )
+ bh_subdivide( bh, 0 );
+
+ totsize = 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!
+ */
+VG_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 );
+ }
+ }
}
-static void bh_debug_node( bh_tree *bh, u32 inode, v3f pos, u32 colour )
+/*
+ * Trace the bh tree all the way down to the leaf nodes where pos is inside
+ */
+VG_STATIC void bh_debug_trace( bh_tree *bh, u32 inode, v3f pos, u32 colour )
{
bh_node *node = &bh->nodes[ inode ];
{
vg_line_boxf( node->bbx, colour );
- bh_debug_node( bh, node->il, pos, colour );
- bh_debug_node( bh, node->ir, pos, colour );
+ bh_debug_trace( bh, node->il, pos, colour );
+ bh_debug_trace( bh, node->ir, pos, colour );
}
else
{
- 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 );
- }
- }
+ bh_debug_leaf( bh, node );
}
}
}
-static int bh_ray( bh_tree *bh, u32 inode, v3f co, v3f dir, ray_hit *hit )
+VG_STATIC int bh_ray( bh_tree *bh, v3f co, v3f dir, ray_hit *hit )
{
+ if( bh->node_count < 2 )
+ return 0;
+
int count = 0;
u32 stack[100];
u32 depth = 2;
stack[0] = 0;
stack[1] = bh->nodes[0].il;
stack[2] = bh->nodes[0].ir;
+
+ v3f dir_inv;
+ dir_inv[0] = 1.0f/dir[0];
+ dir_inv[1] = 1.0f/dir[1];
+ dir_inv[2] = 1.0f/dir[2];
while(depth)
{
bh_node *inode = &bh->nodes[ stack[depth] ];
- if( ray_aabb( inode->bbx, co, dir, hit->dist ) )
+ if( ray_aabb1( inode->bbx, co, dir_inv, hit->dist ) )
{
if( inode->count )
{
u32 idx = inode->start+i;
if( bh->system->cast_ray )
- count += bh->system->cast_ray( bh->user, co, dir, hit );
+ count += bh->system->cast_ray( bh->user, idx, co, dir, hit );
else
count ++;
}
return count;
}
-static int bh_select( bh_tree *bh, boxf box, u32 *buffer, int len )
+typedef struct bh_iter bh_iter;
+struct bh_iter
{
- int count = 0;
- u32 stack[100];
- u32 depth = 2;
+ struct
+ {
+ int id, depth;
+ }
+ stack[64];
- stack[0] = 0;
- stack[1] = bh->nodes[0].il;
- stack[2] = bh->nodes[0].ir;
-
- while(depth)
+ int depth, i;
+};
+
+VG_STATIC void bh_iter_init( int root, bh_iter *it )
+{
+ it->stack[0].id = root;
+ it->stack[0].depth = 0;
+ it->depth = 0;
+ it->i = 0;
+}
+
+VG_STATIC int bh_next( bh_tree *bh, bh_iter *it, boxf box, int *em )
+{
+ while( it->depth >= 0 )
{
- bh_node *inode = &bh->nodes[ stack[depth] ];
- if( box_overlap( inode->bbx, box ) )
+ bh_node *inode = &bh->nodes[ it->stack[it->depth].id ];
+
+ /* Only process overlapping nodes */
+ if( !box_overlap( inode->bbx, box ) )
+ {
+ 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;
+}
+
+VG_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 )
{
- if( count + inode->count >= len )
+ for( int i=0; i<inode->count; i++ )
{
- vg_error( "Maximum buffer reached!\n" );
- return count;
+ 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;
+ }
}
- for( u32 i=0; i<inode->count; i++ )
- buffer[ count ++ ] = inode->start+i;
-
depth --;
}
else
{
- if( depth+1 >= vg_list_size(stack) )
- {
- vg_error( "Maximum stack reached!\n" );
- return count;
- }
+ queue[depth] = inode->il;
+ queue[depth+1] = inode->ir;
- stack[depth] = inode->il;
- stack[depth+1] = inode->ir;
depth ++;
}
}
else
- {
depth --;
- }
}
- return count;
+ return best_item;
}
#endif /* BVH_H */