97 lines
2.3 KiB
Rust
97 lines
2.3 KiB
Rust
#![allow(dead_code)]
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use core::f32;
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use glam::f32::{Mat2, Mat3, Mat4, Quat, Vec2, Vec3, Vec4};
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pub struct PCG32 {
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state: u64,
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inc: u64,
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}
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impl PCG32 {
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pub fn seed(initstate: u64, initseq: u64) -> Self {
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let mut rng = PCG32 {
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state: 0,
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inc: (initseq << 1) | 1,
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};
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rng.next_u32();
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rng.state = rng.state.wrapping_add(initstate);
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rng.next_u32();
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rng
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}
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pub fn default() -> Self {
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PCG32::seed(0x853c49e6748fea9b, 0xda3e39cb94b95bdb)
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}
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pub fn next_u32(&mut self) -> u32 {
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let oldstate = self.state;
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self.state = oldstate
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.wrapping_mul(6364136223846793005)
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.wrapping_add(self.inc | 1);
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let xorshifted = ((oldstate >> 18) ^ oldstate) >> 27;
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let rot = oldstate >> 59;
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((xorshifted >> rot) | (xorshifted << (rot.wrapping_neg() & 31))) as u32
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}
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pub fn next_f32(&mut self) -> f32 {
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(self.next_u32() & 0xffffff) as f32 / 16777216.0
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}
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}
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pub fn random_vec2(rng: &mut PCG32) -> Vec2 {
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Vec2::new(rng.next_f32(), rng.next_f32())
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}
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pub fn random_vec3(rng: &mut PCG32) -> Vec3 {
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Vec3::new(rng.next_f32(), rng.next_f32(), rng.next_f32())
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}
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pub fn random_vec4(rng: &mut PCG32) -> Vec4 {
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Vec4::new(
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rng.next_f32(),
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rng.next_f32(),
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rng.next_f32(),
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rng.next_f32(),
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)
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}
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pub fn random_nonzero_vec3(rng: &mut PCG32) -> Vec3 {
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loop {
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let v = random_vec3(rng);
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if v.length_squared() > 0.01 {
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return v;
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}
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}
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}
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pub fn random_f32(rng: &mut PCG32) -> f32 {
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rng.next_f32()
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}
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pub fn random_radians(rng: &mut PCG32) -> f32 {
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-f32::consts::PI + rng.next_f32() * 2.0 * f32::consts::PI
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}
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pub fn random_quat(rng: &mut PCG32) -> Quat {
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let yaw = random_radians(rng);
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let pitch = random_radians(rng);
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let roll = random_radians(rng);
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Quat::from_rotation_ypr(yaw, pitch, roll)
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}
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pub fn random_mat2(rng: &mut PCG32) -> Mat2 {
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Mat2::from_cols(random_vec2(rng), random_vec2(rng))
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}
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pub fn random_mat3(rng: &mut PCG32) -> Mat3 {
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Mat3::from_cols(random_vec3(rng), random_vec3(rng), random_vec3(rng))
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}
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pub fn random_srt_mat4(rng: &mut PCG32) -> Mat4 {
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Mat4::from_scale_rotation_translation(
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random_nonzero_vec3(rng),
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random_quat(rng),
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random_vec3(rng),
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)
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}
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