Data commit

Task/Plasma-effect/Rust/plasma-effect.rust

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+extern crate image;
+
+use image::ColorType;
+use std::path::Path;
+
+// Framebuffer dimensions
+const WIDTH: usize = 640;
+const HEIGHT: usize = 480;
+
+/// Formula for plasma at any particular address
+fn plasma_pixel(x: f64, y: f64) -> f64 {
+    ((x / 16.0).sin()
+        + (y / 8.0).sin()
+        + ((x + y) / 16.0).sin()
+        + ((x * x + y * y).sqrt() / 8.0).sin()
+        + 4.0)
+        / 8.0
+}
+
+/// Precalculate plasma field lookup-table for performance
+fn create_plasma_lut() -> Vec<f64> {
+    let mut plasma: Vec<f64> = vec![0.0; WIDTH * HEIGHT];
+    for y in 0..HEIGHT {
+        for x in 0..WIDTH {
+            plasma[(y * WIDTH) + x] = plasma_pixel(x as f64, y as f64);
+        }
+    }
+    plasma
+}
+
+/// Convert from HSV float(1.0,1.0,1.0) to RGB u8 tuple (255,255,255).
+/// From https://crates.io/crates/palette 0.5.0 rgb.rs, simplified for example
+fn hsv_to_rgb(hue: f64, saturation: f64, value: f64) -> (u8, u8, u8) {
+    let c = value * saturation;
+    let h = hue * 6.0;
+    let x = c * (1.0 - (h % 2.0 - 1.0).abs());
+    let m = value - c;
+    let (red, green, blue) = match (h % 6.0).floor() as u32 {
+        0 => (c, x, 0.0),
+        1 => (x, c, 0.0),
+        2 => (0.0, c, x),
+        3 => (0.0, x, c),
+        4 => (x, 0.0, c),
+        _ => (c, 0.0, x),
+    };
+    // Convert back to RGB (where components are integers from 0 to 255)
+    (
+        ((red + m) * 255.0).round() as u8,
+        ((green + m) * 255.0).round() as u8,
+        ((blue + m) * 255.0).round() as u8,
+    )
+}
+fn main() {
+    // The bitmap/framebuffer for our application. 3 u8 elements per output pixel
+    let mut framebuffer: Vec<u8> = vec![0; WIDTH * HEIGHT * 3];
+    // Generate a lookup table so we don't do too much math for every pixel.
+    // Do it in a function so that the local one can be immutable.
+    let plasma_lookup_table = create_plasma_lut();
+    // For each (r,g,b) pixel in our output buffer
+    for (index, rgb) in framebuffer.chunks_mut(3).enumerate() {
+        // Lookup the precalculated plasma value
+        let hue_lookup = plasma_lookup_table[index] % 1.0;
+        let (red, green, blue) = hsv_to_rgb(hue_lookup, 1.0, 1.0);
+        rgb[0] = red;
+        rgb[1] = green;
+        rgb[2] = blue;
+    }
+    // Save our plasma image to out.png
+    let output_path = Path::new("out.png");
+    match image::save_buffer(
+        output_path,
+        framebuffer.as_slice(),
+        WIDTH as u32,
+        HEIGHT as u32,
+        ColorType::RGB(8),
+    ) {
+        Err(e) => println!("Error writing output image:\n{}", e),
+        Ok(_) => println!("Output written to:\n{}", output_path.to_str().unwrap()),
+    }
+}