mirror of
https://github.com/fluencelabs/assemblyscript
synced 2025-04-25 07:02:13 +00:00
91 lines
2.9 KiB
TypeScript
91 lines
2.9 KiB
TypeScript
// see: https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
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const RGB_ALIVE = 0xE692D3;
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const RGB_DEAD = 0x851BA6;
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var w: i32, h: i32, s: i32;
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/** Gets an input pixel in the range [0, s]. */
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@inline
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function get(x: u32, y: u32): u32 {
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return load<u32>((y * w + x) << 2);
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}
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/** Sets an output pixel in the range [s, 2*s]. */
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@inline
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function set(x: u32, y: u32, v: u32): void {
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store<u32>((s + y * w + x) << 2, v);
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}
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/** Sets an output pixel in the range [s, 2*s] while fading it out. */
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@inline
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function set_fade(x: u32, y: u32, v: u32): void {
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var a = max<i32>((v >>> 24) - 7, 0);
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set(x, y, (a << 24) | (v & 0x00ffffff));
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}
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/** Initializes width and height. Called once from JS. */
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export function init(width: i32, height: i32, seed: f64): void {
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w = width;
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h = height;
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s = width * height;
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// Start by filling output with random live cells.
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for (let y = 0; y < h; ++y) {
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for (let x = 0; x < w; ++x) {
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set(x, y, JSMath.random() > 0.15 ? RGB_DEAD & 0x00ffffff : RGB_ALIVE | 0xff000000);
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}
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}
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}
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/** Performs one step. Called about 30 times a second from JS. */
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export function step(): void {
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var hm1 = h - 1, // h - 1
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wm1 = w - 1; // w - 1
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// The universe of the Game of Life is an infinite two-dimensional orthogonal grid of square
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// "cells", each of which is in one of two possible states, alive or dead.
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for (let y = 0; y < h; ++y) {
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let ym1 = y == 0 ? hm1 : y - 1,
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yp1 = y == hm1 ? 0 : y + 1;
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for (let x = 0; x < w; ++x) {
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let xm1 = x == 0 ? wm1 : x - 1,
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xp1 = x == wm1 ? 0 : x + 1;
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// Every cell interacts with its eight neighbours, which are the cells that are horizontally,
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// vertically, or diagonally adjacent:
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let tl = get(xm1, ym1);
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let tm = get(x , ym1);
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let tr = get(xp1, ym1);
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let ml = get(xm1, y );
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let mm = get(x , y );
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let mr = get(xp1, y );
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let bl = get(xm1, yp1);
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let bm = get(x , yp1);
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let br = get(xp1, yp1);
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// Least significant bit indicates alive or dead, others are ARGB.
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let aliveNeighbors = (
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(tl & 1) + (tm & 1) + (tr & 1) +
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(ml & 1) + (mr & 1) +
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(bl & 1) + (bm & 1) + (br & 1)
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);
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let alive = mm & 1;
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if (alive) {
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// A live cell with fewer than 2 live neighbors dies, as if caused by underpopulation.
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// A live cell with more than 3 live neighbors dies, as if by overpopulation.
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if (aliveNeighbors < 2 || aliveNeighbors > 3) set(x, y, RGB_DEAD | 0xff000000);
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// A live cell with 2 or 3 live neighbors lives on to the next generation.
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else set_fade(x, y, mm);
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} else {
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// A dead cell with exactly 3 live neighbors becomes a live cell, as if by reproduction.
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if (aliveNeighbors == 3) set(x, y, RGB_ALIVE | 0xff000000);
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// Otherwise the dead cell remains dead.
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else set_fade(x, y, mm);
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}
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}
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}
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}
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