noise (this is iter 4)

front/index.js

@@ -1,8 +1,8 @@
 var ctx;
 var image;
 var memory;
-const width = 256;
+const width = 80;
-const height = 224;
+const height = 60;
 
 function blit_frame() {
     ctx.putImageData(image, 0, 0);

pirates/Cargo.lock

@@ -2,6 +2,109 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "approx"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cab112f0a86d568ea0e627cc1d6be74a1e9cd55214684db5561995f6dad897c6"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
+name = "libm"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7012b1bbb0719e1097c47611d3898568c546d597c2e74d66f6087edd5233ff4"
+
+[[package]]
+name = "nalgebra"
+version = "0.32.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "307ed9b18cc2423f29e83f84fd23a8e73628727990181f18641a8b5dc2ab1caa"
+dependencies = [
+ "approx",
+ "num-complex",
+ "num-rational",
+ "num-traits",
+ "simba",
+ "typenum",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ba157ca0885411de85d6ca030ba7e2a83a28636056c7c699b07c8b6f7383214"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "225d3389fb3509a24c93f5c29eb6bde2586b98d9f016636dff58d7c6f7569cd9"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0638a1c9d0a3c0914158145bc76cff373a75a627e6ecbfb71cbe6f453a5a19b0"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f30b0abd723be7e2ffca1272140fac1a2f084c77ec3e123c192b66af1ee9e6c2"
+dependencies = [
+ "autocfg",
+ "libm",
+]
+
+[[package]]
+name = "paste"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de3145af08024dea9fa9914f381a17b8fc6034dfb00f3a84013f7ff43f29ed4c"
+
 [[package]]
 name = "pirates"
 version = "0.1.0"
+dependencies = [
+ "libm",
+ "nalgebra",
+]
+
+[[package]]
+name = "simba"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "061507c94fc6ab4ba1c9a0305018408e312e17c041eb63bef8aa726fa33aceae"
+dependencies = [
+ "approx",
+ "num-complex",
+ "num-traits",
+ "paste",
+]
+
+[[package]]
+name = "typenum"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497961ef93d974e23eb6f433eb5fe1b7930b659f06d12dec6fc44a8f554c0bba"

pirates/Cargo.toml

@@ -11,3 +11,9 @@ opt-level = 's'
 crate-type = ["cdylib"]
 
 [dependencies]
+libm = "0.2.7"
+
+[dependencies.nalgebra]
+version = "0.32.3"
+default-features = false
+features = ["libm"]

pirates/src/lib.rs

@@ -1,12 +1,16 @@
 #![no_std]
 
-use core::sync::atomic::{AtomicU32, Ordering};
-
 #[panic_handler]
 fn handle_panic(_: &core::panic::PanicInfo) -> ! {
     loop {}
 }
 
+
+use core::sync::atomic::{AtomicU32, Ordering};
+use libm::{self, Libm};
+extern crate nalgebra as na;
+use nalgebra::{Vector2};
+
 extern {
     fn blit_frame();
     fn blit_text(text: *const u8, len: u32, x: i32, y: i32, size: u8);
@@ -21,14 +25,16 @@ fn draw_text(text: &str, x: i32, y: i32, size: u8) {
     }
 }
 
-const WIDTH: usize = 256;
+const WIDTH: usize = 80;
-const HEIGHT: usize = 224;
+const HEIGHT: usize = 60;
 
 #[no_mangle]
 static mut BUFFER: [u32; WIDTH * HEIGHT] = [0; WIDTH * HEIGHT];
 
 static FRAME: AtomicU32 = AtomicU32::new(0);
 
+static mut RAND: noise::PerlinBuf = [0; 512];
+
 #[no_mangle]
 pub unsafe extern fn frame_entry() {
     // calling from multiple threads is ub
@@ -37,14 +43,30 @@ pub unsafe extern fn frame_entry() {
 
 fn render_frame(buffer: &mut [u32; WIDTH*HEIGHT]) {
     let frame = FRAME.fetch_add(1, Ordering::Relaxed);
+
+    if frame == 1 {
+        unsafe {
+            RAND = noise::generate();
+        }
+    }
+    let rand = unsafe {
+        RAND
+    };
+
     for y in 0..HEIGHT {
         for x in 0..WIDTH {
-            buffer[y*WIDTH + x] = frame.wrapping_add((x^y) as u32) | 0xFF000000;
+            let point = Vector2::new((x+frame as usize) as f32,y as f32)*100.0;
+            let mut n = noise::noise(point / 600.0, rand) * 2.0;
+            n += noise::noise(point / 300.0, rand) * 1.0;
+            n += noise::noise(point / 150.0, rand) * 0.5;
+            n += noise::noise(point / 75.0, rand) * 0.25;
+            n += noise::noise(point / 37.5, rand) * 0.125;
+            buffer[y*WIDTH + x] = (((n*0.5+0.5)*256.0) as u32) << 16| 0xFF005000;
         }
     }
     unsafe { blit_frame(); }
 
-    draw_text("hi from rust", 0,100,1);
+    draw_text("hi from rust", 0,100,3);
 }
 
 #[cfg(test)]
@@ -57,3 +79,74 @@ mod tests {
         assert_eq!(result, 64);
     }
 }
+
+mod noise {
+    use libm::Libm;
+    use nalgebra::Vector2;
+
+    pub type PerlinBuf = [u32; 512];
+
+    pub fn generate() -> PerlinBuf {
+        let mut rand = 42424242;
+        let mut data: PerlinBuf = [0; 512];
+        for item in data.iter_mut() {
+            rand = xorshift(rand);
+            *item = rand;
+        }
+
+        data
+    }
+
+    fn xorshift(state: u32) -> u32 {
+        // impl from wikipedia
+        let mut state = state;
+        state ^= state << 13;
+        state ^= state >> 17;
+        state ^= state << 5;
+        state
+    }
+
+    fn fade(t: f32) -> f32 {
+        t*t*t*(t*(t*6.0-15.0)+10.0)
+    }
+
+    fn lerp(a: f32, b:f32, d:f32) -> f32 {
+        a * (1.0-d) + b * d
+    }
+
+    fn grad(p: Vector2<f32>, b: PerlinBuf) -> Vector2<f32> {
+        const width: usize = 16;
+
+
+        let x = p.x as usize % width;
+        let y = p.y as usize % width;
+
+        let one = b[x*width + y] as f32;
+        let two = b[x*width + y + 256] as f32;
+
+        Vector2::new(one, two).normalize()
+    }
+
+    pub fn noise(p: Vector2<f32>, b: PerlinBuf) -> f32 {
+        let p0 = Vector2::new(libm::floorf(p.x), libm::floorf(p.y));
+        let p1 = p0 + Vector2::new(1.0, 0.0);
+        let p2 = p0 + Vector2::new(0.0, 1.0);
+        let p3 = p0 + Vector2::new(1.0, 1.0);
+
+        let g0 = grad(p0, b);
+        let g1 = grad(p1, b);
+        let g2 = grad(p2, b);
+        let g3 = grad(p3, b);
+
+        let tx = p.x - p0.x;
+        let ftx = fade(tx);
+        let ty = p.y - p0.y;
+        let fty = fade(ty);
+
+        let p0p1 = (1.0 - ftx) * g0.dot(&(p-p0)) + ftx * g1.dot(&(p-p1));
+        let p2p3 = (1.0 - ftx) * g2.dot(&(p-p2)) + ftx * g3.dot(&(p-p3));
+
+
+        (1.0 - fty) * p0p1 + fty * p2p3
+    }
+}