d_a = 1
d_b = 0.5
feed = 0.055
k = 0.062
directNeighborWeight = 0.2
diagonalNeighborWeight = 0.05
function laplace([i, j], val, grid) {
let sum = 0;
const center = grid[i][j];
sum += -1 * center[val];
const directNeighbors = [
[i - 1 < 0 ? colSize - 1 : i - 1, j],
[(i + 1) % colSize, j],
[i, j - 1 < 0 ? colSize - 1 : j - 1],
[i, (j + 1) % colSize]
];
directNeighbors.forEach(
([x, y]) => (sum += directNeighborWeight * grid[x][y][val])
);
const diagonalNeighbors = [
[(i + 1) % colSize, j - 1 < 0 ? colSize - 1 : j - 1],
[(i + 1) % colSize, (j + 1) % colSize],
[i - 1 < 0 ? colSize - 1 : i - 1, (j + 1) % colSize],
[i - 1 < 0 ? colSize - 1 : i - 1, j - 1 < 0 ? colSize - 1 : j - 1]
];
diagonalNeighbors.forEach(
([x, y]) => (sum += diagonalNeighborWeight * grid[x][y][val])
);
return sum;
}
function nextGrid(grid) {
for (let i = 0; i < grid.length; ++i) {
for (let j = 0; j < grid[i].length; ++j) {
const { a, b } = grid[i][j];
grid[i][j] = {
a: a + (d_a * laplace([i, j], 'a', grid) - a * b * b + feed * (1 - a)),
b: b + d_b * laplace([i, j], 'b', grid) + a * b * b - (k + feed) * b
};
}
}
}
function drawGrid(grid, context) {
for (let i = 0; i < grid.length; ++i) {
for (let j = 0; j < grid[i].length; ++j) {
const { a, b } = grid[i][j];
const c = Math.abs(a - b) * 255;
context.fillStyle = `rgba(${c}, ${c}, ${c}, 1)`;
context.fillRect(i * step, j * step, step, step);
}
}
}
function makeGrid() {
const res = [];
for (let x = 0; x < colSize; ++x) {
const row = [];
for (let y = 0; y < colSize; ++y) {
row.push({
a: 0,
b: Math.floor(Math.random() * 2)
});
}
res.push(row);
}
return res;
}
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