cessen/psychopath
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Handle LDS permutation a little differently.

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This produces identical results, but makes it easier to play
with other types of sequences.
This commit is contained in:
Nathan Vegdahl 2020-02-22 07:34:51 +09:00
parent 022c913757
commit 0b493b09ca
1 changed files with 16 additions and 12 deletions
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28
src/renderer.rs
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@ -240,12 +240,12 @@ impl<'a> Renderer<'a> {
// Generate light paths and initial rays
for y in bucket.y..(bucket.y + bucket.h) {
for x in bucket.x..(bucket.x + bucket.w) {
let offset = hash_u32(((x as u32) << 16) ^ (y as u32), self.seed);
let scramble = hash_u32(((x as u32) << 16) ^ (y as u32), self.seed);
for si in 0..self.spp {
// Calculate image plane x and y coordinates
let (img_x, img_y) = {
let filter_x = fast_logit(get_sample(4, offset + si as u32), 1.5) + 0.5;
let filter_y = fast_logit(get_sample(5, offset + si as u32), 1.5) + 0.5;
let filter_x = fast_logit(get_sample(4, si as u32, scramble), 1.5) + 0.5;
let filter_y = fast_logit(get_sample(5, si as u32, scramble), 1.5) + 0.5;
let samp_x = (filter_x + x as f32) * cmpx;
let samp_y = (filter_y + y as f32) * cmpy;
((samp_x - 0.5) * x_extent, (0.5 - samp_y) * y_extent)
@ -257,12 +257,13 @@ impl<'a> Renderer<'a> {
(x, y),
(img_x, img_y),
(
get_sample(0, offset + si as u32),
get_sample(1, offset + si as u32),
get_sample(0, si as u32, scramble),
get_sample(1, si as u32, scramble),
),
get_sample(2, offset + si as u32),
map_0_1_to_wavelength(get_sample(3, offset + si as u32)),
offset + si as u32,
get_sample(2, si as u32, scramble),
map_0_1_to_wavelength(get_sample(3, si as u32, scramble)),
si as u32,
scramble,
);
paths.push(path);
rays.push(ray, false);
@ -369,6 +370,7 @@ pub struct LightPath {
pixel_co: (u32, u32),
lds_offset: u32,
lds_scramble: u32,
dim_offset: Cell<u32>,
time: f32,
wavelength: f32,
@ -392,6 +394,7 @@ impl LightPath {
time: f32,
wavelength: f32,
lds_offset: u32,
lds_scramble: u32,
) -> (LightPath, Ray) {
(
LightPath {
@ -400,6 +403,7 @@ impl LightPath {
pixel_co: pixel_co,
lds_offset: lds_offset,
lds_scramble: lds_scramble,
dim_offset: Cell::new(6),
time: time,
wavelength: wavelength,
@ -426,7 +430,7 @@ impl LightPath {
fn next_lds_samp(&self) -> f32 {
let dimension = self.dim_offset.get();
self.dim_offset.set(dimension + 1);
get_sample(dimension, self.lds_offset)
get_sample(dimension, self.lds_offset, self.lds_scramble)
}
fn next(
@ -681,12 +685,12 @@ impl LightPath {
/// and switching to random samples at higher dimensions where
/// LDS samples aren't available.
#[inline(always)]
fn get_sample(dimension: u32, i: u32) -> f32 {
fn get_sample(dimension: u32, i: u32, scramble: u32) -> f32 {
use crate::hash::hash_u32_to_f32;
if dimension < halton::MAX_DIMENSION {
halton::sample(dimension, i)
halton::sample(dimension, i + scramble)
} else {
hash_u32_to_f32(dimension, i)
hash_u32_to_f32(dimension, i + scramble)
}
}