Nathan Vegdahl
d71fd3b5c8
After implementation, it does appear to make rendering slower by a noticable bit compared to what I was doing before. At very low sampling rates it does provide a bit of visual improvement, but by the time you get to even just 16 samples per pixel its benefits seem to disappear. Due to the slow down and the minimal gains, I'll be removing this in the next commit. But I want to commit it so I don't lose the code, since it was an interesting experiment with some promising results.
42 lines
986 B
Rust
42 lines
986 B
Rust
use std;
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pub fn hash_u32(n: u32, seed: u32) -> u32 {
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let mut hash = n;
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for _ in 0..3 {
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hash = hash.wrapping_mul(1936502639);
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hash ^= hash.wrapping_shr(16);
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hash = hash.wrapping_add(seed);
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}
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return hash;
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}
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pub fn hash_u64(n: u64, seed: u64) -> u64 {
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let mut hash = n;
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for _ in 0..4 {
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hash = hash.wrapping_mul(32416190071 * 314604959);
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hash ^= hash.wrapping_shr(32);
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hash = hash.wrapping_add(seed);
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}
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return hash;
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}
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/// Returns a random float in [0, 1] based on 'n' and a seed.
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/// Generally use n for getting a bunch of different random
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/// numbers, and use seed to vary between runs.
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pub fn hash_u32_to_f32(n: u32, seed: u32) -> f32 {
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let mut hash = n;
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for _ in 0..3 {
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hash = hash.wrapping_mul(1936502639);
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hash ^= hash.wrapping_shr(16);
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hash = hash.wrapping_add(seed);
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}
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const INV_MAX: f32 = 1.0 / std::u32::MAX as f32;
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return hash as f32 * INV_MAX;
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}
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