From 2b8bb0b705055bd6da8b09de1855254520c1a306 Mon Sep 17 00:00:00 2001
From: Quaternions <krakow20@gmail.com>
Date: Sun, 18 Aug 2024 14:42:02 -0700
Subject: [PATCH] bvh: remove unnecessary work
---
src/bvh.rs | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/src/bvh.rs b/src/bvh.rs
index ee73355..b76c239 100644
--- a/src/bvh.rs
+++ b/src/bvh.rs
@@ -121,13 +121,11 @@ fn generate_bvh_node<T>(boxen:Vec<(T,Aabb)>,force:bool)->BvhNode<T>{
aabb,
}
}else{
- let mut octant=std::collections::HashMap::with_capacity(n);//this ids which octant the boxen is put in
let mut sort_x=Vec::with_capacity(n);
let mut sort_y=Vec::with_capacity(n);
let mut sort_z=Vec::with_capacity(n);
for (i,(_,aabb)) in boxen.iter().enumerate(){
let center=aabb.center();
- octant.insert(i,0);
sort_x.push((i,center.x()));
sort_y.push((i,center.y()));
sort_z.push((i,center.z()));
@@ -139,26 +137,26 @@ fn generate_bvh_node<T>(boxen:Vec<(T,Aabb)>,force:bool)->BvhNode<T>{
let median_x=sort_x[h].1;
let median_y=sort_y[h].1;
let median_z=sort_z[h].1;
- for (i,c) in sort_x{
- if median_x<c{
- octant.insert(i,octant[&i]+1<<0);
- }
+ //partition point gives the first index for which the predicate evaluates to false
+ let first_index_gt_median_x=sort_x.partition_point(|tup|!(median_x<tup.1));
+ let first_index_gt_median_y=sort_y.partition_point(|tup|!(median_y<tup.1));
+ let first_index_gt_median_z=sort_z.partition_point(|tup|!(median_z<tup.1));
+ //this ids which octant the boxen is put in
+ let mut octant=vec![0;n];
+ for &(i,_) in &sort_x[first_index_gt_median_x..]{
+ octant[i]+=1<<0;
}
- for (i,c) in sort_y{
- if median_y<c{
- octant.insert(i,octant[&i]+1<<1);
- }
+ for &(i,_) in &sort_y[first_index_gt_median_y..]{
+ octant[i]+=1<<1;
}
- for (i,c) in sort_z{
- if median_z<c{
- octant.insert(i,octant[&i]+1<<2);
- }
+ for &(i,_) in &sort_z[first_index_gt_median_z..]{
+ octant[i]+=1<<2;
}
//generate lists for unique octant values
let mut list_list=Vec::with_capacity(8);
let mut octant_list=Vec::with_capacity(8);
for (i,(data,aabb)) in boxen.into_iter().enumerate(){
- let octant_id=octant[&i];
+ let octant_id=octant[i];
let list_id=if let Some(list_id)=octant_list.iter().position(|&id|id==octant_id){
list_id
}else{