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use std::eprintln;
use crate::vec3::{Vec3, Point3};
const POINT_COUNT: usize = 256;
// Mix-in images are necessarily monochrome, so each data entry is a pixel.
pub struct MixInImage {
width: usize,
height: usize,
data: Vec<f64>,
}
impl MixInImage {
pub fn from_bmp(bmp_data: &Vec<u8>) -> Self {
let data_position = u32::from_le_bytes([
bmp_data[0x0A],
bmp_data[0x0B],
bmp_data[0x0C],
bmp_data[0x0D],
]);
// assuming windows BITMAPINFOHEADER, these are i32
let width = i32::from_le_bytes([
bmp_data[0x12],
bmp_data[0x13],
bmp_data[0x14],
bmp_data[0x15],
]) as usize;
let height = i32::from_le_bytes([
bmp_data[0x16],
bmp_data[0x17],
bmp_data[0x18],
bmp_data[0x19],
]) as usize;
// assuming 3 channels, all of which are equal
let data = bmp_data[(data_position as usize)..bmp_data.len()].iter().skip(2).step_by(3).map(|x| *x as f64 / 255.0).collect();
Self {
width,
height,
data,
}
}
pub fn get(&self, point: &Point3) -> &f64 {
let disc_x = ((point.x * self.width as f64) % self.width as f64) as usize;
let disc_y = ((point.y * self.height as f64) % self.height as f64) as usize;
self.data.get((disc_y * self.width) + disc_x).unwrap()
}
}
pub struct Perlin {
ranvec: Vec<Vec3>,
perm_x: Vec<usize>,
perm_y: Vec<usize>,
perm_z: Vec<usize>,
}
impl Perlin {
pub fn new() -> Self {
let mut ranvec = Vec::with_capacity(POINT_COUNT);
for _ in 0..POINT_COUNT {
ranvec.push(Vec3::random_in_range(-1.0, 1.0).unit_vector());
}
Self {
ranvec,
perm_x: Self::generate_perm(),
perm_y: Self::generate_perm(),
perm_z: Self::generate_perm(),
}
}
pub fn turb(&self, point: &Point3, depth: u32) -> f64 {
let mut accum = 0.0;
let mut temp_point = point.clone();
let mut weight = 1.0;
for _ in 0..depth {
accum += weight * self.noise(&temp_point);
weight *= 0.5;
temp_point *= 2.0;
}
accum.abs()
}
pub fn turb_dsw(&self, point: &Point3, depth: u32, factor: f64) -> f64 {
let mut accum = 0.0;
let mut temp_point = point.clone();
let mut weight = 1.0;
for _ in 0..depth {
accum += weight * self.noise(&temp_point);
temp_point *= 2.0;
temp_point += temp_point.xy_diff(&|p: &Vec3| -> f64 {weight * self.noise(p)}) * factor;
weight *= 0.5;
}
accum.abs()
}
pub fn turb_dsw_mixin(&self, point: &Point3, depth: u32, factor: f64, mixin: &MixInImage, mixin_factor: f64, mixin_strength: f64) -> f64 {
let mut accum = 0.0;
let mut temp_point = point.clone();
let mut mixin_point = point.clone();
let mut weight = 1.0;
for _ in 0..depth {
accum += weight * (1.0 - mixin_strength) * self.noise(&temp_point);
temp_point *= 2.0;
let diff = temp_point.xy_diff(&|p: &Vec3| -> f64 {weight * self.noise(p)});
temp_point += &diff * factor;
mixin_point += &diff * mixin_factor;
accum += weight * mixin_strength * mixin.get(&mixin_point);
weight *= 0.5;
}
accum.abs()
}
pub fn noise(&self, point: &Point3) -> f64 {
let u = point.x - point.x.floor();
let v = point.y - point.y.floor();
let w = point.z - point.z.floor();
let i = point.x.floor() as i32;
let j = point.y.floor() as i32;
let k = point.z.floor() as i32;
let mut c: [[[Vec3; 2]; 2]; 2] = Default::default();
for di in 0..2 {
for dj in 0..2 {
for dk in 0..2 {
c[di][dj][dk] = self
.ranvec
.get(
(self.perm_x.get(((i + di as i32) & 255) as usize).unwrap()
^ self.perm_y.get(((j + dj as i32) & 255) as usize).unwrap()
^ self.perm_z.get(((k + dk as i32) & 255) as usize).unwrap())
as usize,
)
.unwrap().clone();
}
}
}
Self::trilinear_interpolate(c, u, v, w)
}
fn trilinear_interpolate(c: [[[Vec3; 2]; 2]; 2], u: f64, v: f64, w: f64) -> f64 {
let uu = u * u * (3.0 - 2.0 * u);
let vv = v * v * (3.0 - 2.0 * v);
let ww = w * w * (3.0 - 2.0 * w);
let mut accum: f64 = 0.0;
for i in 0..2 {
for j in 0..2 {
for k in 0..2 {
let i_f = i as f64;
let j_f = j as f64;
let k_f = k as f64;
let weight_v = Vec3 { x: u - i_f, y: v - j_f, z: w - k_f };
accum += (i_f * uu + (1.0 - i_f) * (1.0 - uu)) *
(j_f * vv + (1.0 - j_f) * (1.0 - vv)) *
(k_f * ww + (1.0 - k_f) * (1.0 - ww)) *
c[i][j][k].dot(&weight_v);
}
}
}
accum
}
fn generate_perm() -> Vec<usize> {
let mut p = (0..POINT_COUNT).collect();
Self::permute(&mut p, POINT_COUNT);
p
}
fn permute(p: &mut Vec<usize>, n: usize) {
for i in (1..n).rev() {
p.swap(i, rand::random::<usize>() % i);
}
}
}
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