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Make the mandelbrot example a bit more fun as well

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dcodeIO
2018-04-20 15:36:01 +02:00
parent b53b3e08ec
commit 4eade0f319
9 changed files with 1348 additions and 1333 deletions
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70
examples/mandelbrot/assembly/index.ts
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@ -1,41 +1,47 @@
// see: https://en.wikipedia.org/wiki/Mandelbrot_set
/** Computes the number of iterations in the rectangle `width` x `height`, limited to `max`. */
export function compute(width: u32, height: u32, limit: u32): void {
/** Number of discrete color values on the JS side. */
const NUM_COLORS = 2048;
/** Computes a single line in the rectangle `width` x `height`. */
export function computeLine(y: u32, width: u32, height: u32, limit: u32): void {
var translateX = width / 1.6;
var translateY = height / 2.0;
var scale = 10.0 / min(3 * width, 4 * height);
for (let y: u32 = 0; y < height; ++y) {
let imaginary = (y - translateY) * scale;
for (let x: u32 = 0; x < width; ++x) {
let real = (x - translateX) * scale;
var imaginary = (y - translateY) * scale;
for (let x: u32 = 0; x < width; ++x) {
let real = (x - translateX) * scale;
// Iterate until either the escape radius or iteration limit is exceeded
let ix = 0.0, iy = 0.0, ixsq: f64, iysq: f64;
let iteration: u32 = 0;
while ((ixsq = ix * ix) + (iysq = iy * iy) <= 4.0) {
let t = ixsq - iysq + real;
iy = 2.0 * ix * iy + imaginary;
ix = t;
if (iteration >= limit) break;
++iteration;
}
// Do a few extra iterations to reduce error margin
for (let i = 0; i < 4; ++i) {
let t = (ixsq = ix * ix) - (iysq = iy * iy) + real;
iy = 2.0 * ix * iy + imaginary;
ix = t;
}
// Renormalize, see: http://linas.org/art-gallery/escape/escape.html
let frac: f64 = JSMath.log(JSMath.log(sqrt(ix * ix + iy * iy))) / JSMath.LN2;
if (frac > 0) {
let norm: f64 = max<f64>(min<f64>((<f64>(iteration + 1) - frac) / limit, 1.0), 0.0);
store<u16>((y * width + x) << 1, <u32>(2047 * norm));
} else {
store<u16>((y * width + x) << 1, iteration * 2047 / limit);
}
// Iterate until either the escape radius or iteration limit is exceeded
let ix = 0.0, iy = 0.0, ixsq: f64, iysq: f64;
let iteration: u32 = 0;
while ((ixsq = ix * ix) + (iysq = iy * iy) <= 4.0) {
let ix_new = ixsq - iysq + real;
iy = 2.0 * ix * iy + imaginary;
ix = ix_new;
if (iteration >= limit) break;
++iteration;
}
// Do a few extra iterations to reduce error margin
for (let i = 0; i < 5 && iteration < limit; ++i, ++iteration) {
let ix_new = ix * ix - iy * iy + real;
iy = 2.0 * ix * iy + imaginary;
ix = ix_new;
}
// Renormalize, see: http://linas.org/art-gallery/escape/escape.html
let frac: f64 = JSMath.log(JSMath.log(sqrt(ix * ix + iy * iy))) / JSMath.LN2;
store<u16>((y * width + x) << 1,
isFinite(frac)
? <u32>((NUM_COLORS - 1) * clamp((iteration + 1 - frac) / limit, 0.0, 1.0))
: (NUM_COLORS - 1) * iteration / limit
);
}
}
/** Clamps a value between the given minimum and maximum. */
@inline
function clamp<T>(value: T, minValue: T, maxValue: T): T {
return min(max(value, minValue), maxValue);
}