extracted noise and sampler modules
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4 changed files with 116 additions and 107 deletions
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@ -1,8 +1,8 @@
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var ctx;
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var image;
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var memory;
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const width = 256;
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const height = 224;
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const width = 160;
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const height = 144;
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function blit_frame() {
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ctx.putImageData(image, 0, 0);
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@ -14,6 +14,9 @@ use libm::{self, Libm};
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extern crate nalgebra as na;
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use nalgebra::{Vector2};
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mod sampler;
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mod noise;
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extern {
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fn blit_frame();
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fn blit_text(text: *const u8, len: u32, x: i32, y: i32, size: u8);
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@ -28,8 +31,8 @@ fn draw_text(text: &str, x: i32, y: i32, size: u8) {
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}
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}
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const WIDTH: usize = 256;
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const HEIGHT: usize = 224;
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const WIDTH: usize = 160;
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const HEIGHT: usize = 144;
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#[no_mangle]
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static mut BUFFER: [u32; WIDTH * HEIGHT] = [0; WIDTH * HEIGHT];
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@ -77,7 +80,7 @@ fn render_frame(buffer: &mut [u32; WIDTH*HEIGHT]) {
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let offset = Vector2::new(64120.0, 7320.0);
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let point = point + offset;
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let mut n = 0.0;
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n += (sample_map_inter(point / 64.0, &MAP)-0.5)* 0.6;
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n += (sampler::sample_map_inter(point / 64.0, &MAP)-0.5)* 0.6;
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n += noise::noise(point / 64.0, rand) / 1.0;
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n += noise::noise(point / 32.0, rand) / 2.0;
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n += noise::noise(point / 16.0, rand) / 4.0;
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@ -102,38 +105,6 @@ fn render_frame(buffer: &mut [u32; WIDTH*HEIGHT]) {
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//draw_text("hi from rust", 0,100,30);
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}
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fn sample_map_inter(point: Vector2<f32>, map: &[u8]) -> f32 {
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let x = libm::floorf(point.x) as usize % MAP_WIDTH;
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let y = libm::floorf(point.y) as usize % MAP_HEIGHT;
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let p0 = Vector2::new(libm::floorf(point.x), libm::floorf(point.y));
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let p1 = p0 + Vector2::new(1.0, 0.0);
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let p2 = p0 + Vector2::new(0.0, 1.0);
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let p3 = p0 + Vector2::new(1.0, 1.0);
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let tx = point.x - libm::floorf(point.x);
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let ty = point.y - libm::floorf(point.y);
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let top = (1.0 - tx) * sample_map(p0, map) as f32 + tx * sample_map(p1, map) as f32;
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let bot = (1.0 - tx) * sample_map(p2, map) as f32 + tx * sample_map(p3, map) as f32;
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(1.0-ty) * top + ty * bot
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}
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fn sample_map(point: Vector2<f32>, map: &[u8]) -> u8 {
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const MARGIN: usize = 3;
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let x = libm::floorf(point.x) as usize % (MAP_WIDTH + MARGIN);
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let y = libm::floorf(point.y) as usize % (MAP_HEIGHT + MARGIN);
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if x >= MAP_WIDTH || y >= MAP_HEIGHT {
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if x-y > 12 {
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return 1;
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}
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return 0;
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}
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map[y*MAP_WIDTH + x]
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}
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#[cfg(test)]
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mod tests {
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@ -146,73 +117,3 @@ mod tests {
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}
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}
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mod noise {
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use libm::Libm;
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use nalgebra::Vector2;
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pub type PerlinBuf = [u32; 512];
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pub fn generate(seed: u32) -> PerlinBuf {
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let mut rand = seed;
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let mut data: PerlinBuf = [0; 512];
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for item in data.iter_mut() {
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rand = xorshift(rand);
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*item = rand;
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}
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data
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}
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fn xorshift(state: u32) -> u32 {
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// impl from wikipedia
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let mut state = state;
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state ^= state << 13;
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state ^= state >> 17;
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state ^= state << 5;
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state
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}
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fn fade(t: f32) -> f32 {
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t*t*t*(t*(t*6.0-15.0)+10.0)
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}
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fn lerp(a: f32, b:f32, d:f32) -> f32 {
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a * (1.0-d) + b * d
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}
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fn grad(p: Vector2<f32>, b: PerlinBuf) -> Vector2<f32> {
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const width: usize = 16;
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let x = p.x as usize % width;
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let y = p.y as usize % width;
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let one = b[x*width + y] as f32;
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let two = b[(x*width + y + 1)%512] as f32;
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Vector2::new(one, two).normalize()
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}
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pub fn noise(p: Vector2<f32>, b: PerlinBuf) -> f32 {
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let p0 = Vector2::new(libm::floorf(p.x), libm::floorf(p.y));
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let p1 = p0 + Vector2::new(1.0, 0.0);
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let p2 = p0 + Vector2::new(0.0, 1.0);
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let p3 = p0 + Vector2::new(1.0, 1.0);
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let g0 = grad(p0, b);
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let g1 = grad(p1, b);
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let g2 = grad(p2, b);
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let g3 = grad(p3, b);
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let tx = p.x - p0.x;
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let ftx = fade(tx);
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let ty = p.y - p0.y;
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let fty = fade(ty);
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let p0p1 = (1.0 - ftx) * g0.dot(&(p-p0)) + ftx * g1.dot(&(p-p1));
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let p2p3 = (1.0 - ftx) * g2.dot(&(p-p2)) + ftx * g3.dot(&(p-p3));
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(1.0 - fty) * p0p1 + fty * p2p3
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}
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}
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68
pirates/src/noise.rs
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68
pirates/src/noise.rs
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@ -0,0 +1,68 @@
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use libm::Libm;
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use nalgebra::Vector2;
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pub type PerlinBuf = [u32; 512];
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pub fn generate(seed: u32) -> PerlinBuf {
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let mut rand = seed;
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let mut data: PerlinBuf = [0; 512];
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for item in data.iter_mut() {
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rand = xorshift(rand);
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*item = rand;
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}
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data
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}
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fn xorshift(state: u32) -> u32 {
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// impl from wikipedia
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let mut state = state;
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state ^= state << 13;
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state ^= state >> 17;
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state ^= state << 5;
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state
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}
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fn fade(t: f32) -> f32 {
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t*t*t*(t*(t*6.0-15.0)+10.0)
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}
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fn lerp(a: f32, b:f32, d:f32) -> f32 {
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a * (1.0-d) + b * d
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}
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fn grad(p: Vector2<f32>, b: PerlinBuf) -> Vector2<f32> {
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const width: usize = 16;
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let x = p.x as usize % width;
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let y = p.y as usize % width;
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let one = b[x*width + y] as f32;
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let two = b[(x*width + y + 1)%512] as f32;
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Vector2::new(one, two).normalize()
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}
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pub fn noise(p: Vector2<f32>, b: PerlinBuf) -> f32 {
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let p0 = Vector2::new(libm::floorf(p.x), libm::floorf(p.y));
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let p1 = p0 + Vector2::new(1.0, 0.0);
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let p2 = p0 + Vector2::new(0.0, 1.0);
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let p3 = p0 + Vector2::new(1.0, 1.0);
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let g0 = grad(p0, b);
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let g1 = grad(p1, b);
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let g2 = grad(p2, b);
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let g3 = grad(p3, b);
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let tx = p.x - p0.x;
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let ftx = fade(tx);
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let ty = p.y - p0.y;
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let fty = fade(ty);
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let p0p1 = (1.0 - ftx) * g0.dot(&(p-p0)) + ftx * g1.dot(&(p-p1));
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let p2p3 = (1.0 - ftx) * g2.dot(&(p-p2)) + ftx * g3.dot(&(p-p3));
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(1.0 - fty) * p0p1 + fty * p2p3
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}
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40
pirates/src/sampler.rs
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40
pirates/src/sampler.rs
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@ -0,0 +1,40 @@
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use super::MAP_HEIGHT;
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use super::MAP_WIDTH;
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use libm::Libm;
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use nalgebra::Vector2;
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pub(crate) fn sample_map_inter(point: Vector2<f32>, map: &[u8]) -> f32 {
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let x = libm::floorf(point.x) as usize % MAP_WIDTH;
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let y = libm::floorf(point.y) as usize % MAP_HEIGHT;
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let p0 = Vector2::new(libm::floorf(point.x), libm::floorf(point.y));
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let p1 = p0 + Vector2::new(1.0, 0.0);
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let p2 = p0 + Vector2::new(0.0, 1.0);
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let p3 = p0 + Vector2::new(1.0, 1.0);
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let tx = point.x - libm::floorf(point.x);
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let ty = point.y - libm::floorf(point.y);
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let top = (1.0 - tx) * sample_map(p0, map) as f32 + tx * sample_map(p1, map) as f32;
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let bot = (1.0 - tx) * sample_map(p2, map) as f32 + tx * sample_map(p3, map) as f32;
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(1.0-ty) * top + ty * bot
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}
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pub(crate) fn sample_map(point: Vector2<f32>, map: &[u8]) -> u8 {
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const MARGIN: usize = 3;
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let x = libm::floorf(point.x) as usize % (MAP_WIDTH + MARGIN);
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let y = libm::floorf(point.y) as usize % (MAP_HEIGHT + MARGIN);
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if x >= MAP_WIDTH || y >= MAP_HEIGHT {
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if x-y > 12 {
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return 1;
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}
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return 0;
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}
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map[y*MAP_WIDTH + x]
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}
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