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Removed golden ratio sampling.

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Turns out it causes interference with the Sobol sampler.

Also tweaked some other things about sampling after removing
golden ratio sampling, to make things better.
This commit is contained in:
Nathan Vegdahl 2020-03-19 19:49:45 +09:00
parent e014df2b1a
commit 3916043f33
2 changed files with 5 additions and 15 deletions
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18
src/renderer.rs
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@ -697,24 +697,14 @@ fn get_sample(dimension: u32, i: u32, pixel_co: (u32, u32), seed: u32) -> f32 {
let scramble = hash_u32(pixel_co.0 ^ (pixel_co.1 << 16), seed); let scramble = hash_u32(pixel_co.0 ^ (pixel_co.1 << 16), seed);
match dimension { match dimension {
0 => { d if d < sobol::MAX_DIMENSION as u32 => {
// Golden ratio sampling.
// NOTE: use this for the wavelength dimension, because
// due to the nature of hero wavelength sampling this ends up
// being crazily more efficient than pretty much any other sampler,
// and reduces variance by a huge amount.
let n = i.wrapping_add(scramble).wrapping_mul(2654435769);
n as f32 * (1.0 / (1u64 << 32) as f32)
}
n if (n - 1) < sobol::MAX_DIMENSION as u32 => {
let dim = n - 1;
// Sobol sampling. // Sobol sampling.
sobol::sample_owen_cranley(dim, i, hash_u32(dim, scramble)) sobol::sample_owen(d, i, hash_u32(d, scramble))
} }
_ => { d => {
// Random sampling. // Random sampling.
use crate::hash::hash_u32_to_f32; use crate::hash::hash_u32_to_f32;
hash_u32_to_f32(dimension ^ (i << 16), scramble) hash_u32_to_f32(d ^ (i << 16), scramble)
} }
} }
} }

2
sub_crates/sobol/build.rs
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@ -7,7 +7,7 @@ use std::{env, fs::File, io::Write, path::Path};
const NUM_DIMENSIONS: usize = 1024; const NUM_DIMENSIONS: usize = 1024;
/// What file to generate the numbers from. /// What file to generate the numbers from.
const DIRECTION_NUMBERS_TEXT: &str = include_str!("direction_numbers/joe-kuo-cessen-3.1024.txt"); const DIRECTION_NUMBERS_TEXT: &str = include_str!("direction_numbers/joe-kuo-other-2.1024.txt");
fn main() { fn main() {
let out_dir = env::var("OUT_DIR").unwrap(); let out_dir = env::var("OUT_DIR").unwrap();