cessen/psychopath
1
0
Fork 0
Code Issues 1 Pull Requests Projects Releases Wiki Activity

Light tree can now be traversed with arbitrary arity.

Browse Source 
Next up is building with configurable arity.
This commit is contained in:
Nathan Vegdahl 2017-06-28 23:20:03 -07:00
parent 27c635982e
commit b891cc943b
1 changed files with 34 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
src/accel/light_tree.rs
View File

@ -9,8 +9,9 @@ use shading::surface_closure::SurfaceClosure;
use super::LightAccel;
use super::objects_split::sah_split;
// const LEVEL_COLLAPSE: usize = 2; // Number of levels of the binary tree to collapse together (1 = no collapsing)
// const ARITY: usize = 1 << LEVEL_COLLAPSE; // Arity of the final tree
const LEVEL_COLLAPSE: usize = 1; // Number of levels of the binary tree to
// collapse together (1 = no collapsing)
const ARITY: usize = 1 << LEVEL_COLLAPSE; // Arity of the final tree
#[derive(Copy, Clone, Debug)]
@ -177,28 +178,40 @@ impl<'a> LightAccel for LightTree<'a> {
let mut tot_prob = 1.0;
let mut n = n;
loop {
if let Node::Inner { children, bounds, .. } = *node {
// Calculate the relative probabilities of the two children
let (p1, p2) = {
let p1 = node_prob(&children[0]);
let p2 = node_prob(&children[1]);
let total = p1 + p2;
if total <= 0.0 {
(0.5, 0.5)
} else {
(p1 / total, p2 / total)
if let Node::Inner { children, .. } = *node {
// Calculate the relative probabilities of the children
let ps = {
let mut ps = [0.0; ARITY];
let mut total = 0.0;
for (i, child) in children.iter().enumerate() {
let p = node_prob(child);
ps[i] = p;
total += p;
}
if total <= 0.0 {
let p = 1.0 / children.len() as f32;
for prob in &mut ps {
*prob = p;
}
} else {
for prob in &mut ps {
*prob = *prob / total;
}
}
ps
};
if n <= p1 {
tot_prob *= p1;
node = &children[0];
n /= p1;
} else {
tot_prob *= p2;
node = &children[1];
n = (n - p1) / p2;
// Pick child and update probabilities
let mut base = 0.0;
for (i, &p) in ps.iter().enumerate() {
if (n <= base + p) || (i == children.len() - 1) {
tot_prob *= p;
node = &children[i];
n = (n - base) / p;
break;
} else {
base += p;
}
}
} else {
break;