diff --git a/island.ts b/island.ts
index d278235..d7a3b95 100644
--- a/island.ts
+++ b/island.ts
@@ -5,6 +5,8 @@ const BLOWUP = 4;
const WIDTH = 240;
const HEIGHT = 135;
+const DEFAULT_SEED = 128;
+
type Lookup2d = (x: number, y: number) => number;
function dim(width: number, height: number): Lookup2d {
return function xy(x: number, y: number) {
@@ -21,10 +23,26 @@ class IslandGrid {
xy: Lookup2d;
+ basePos: number;
+ lobePos1: number;
+ lobePos2: number;
+
+ done = false;
+
constructor(public width: number, public height: number, seed: number) {
this.data = Array(width * height).fill(0);
this.rng = mulberry32(seed);
this.xy = dim(width, height);
+
+ this.basePos = this.data.length >> 1;
+ this.lobePos1 = this.xy(
+ (WIDTH >> 1) + (this.rng() % 48) - 24,
+ (HEIGHT >> 1) + (this.rng() % 48) - 24
+ );
+ this.lobePos2 = this.xy(
+ (WIDTH >> 1) + (this.rng() % 48) - 24,
+ (HEIGHT >> 1) + (this.rng() % 48) - 24
+ );
}
public get(x: number, y: number): number {
@@ -67,6 +85,80 @@ class IslandGrid {
return hitPositions;
}
+
+ public drop(pos: number): void {
+ const lowerNeighbors: number[] = [];
+
+ const check = (adjPos: number) => {
+ if (this.data[adjPos] < this.data[pos]) {
+ lowerNeighbors.push(adjPos);
+ }
+ };
+
+ // try to roll in cardinal directions
+
+ check((pos - this.width) % this.data.length);
+ check((pos - 1) % this.data.length);
+ check((pos + 1) % this.data.length);
+ check((pos + this.width) % this.data.length);
+
+ if (lowerNeighbors.length > 0) {
+ const downhill = lowerNeighbors[this.rng() % lowerNeighbors.length];
+ return this.drop(downhill);
+ }
+
+ // try to roll in diagonal directions
+
+ check((pos - this.width - 1) % this.data.length);
+ check((pos - this.width + 1) % this.data.length);
+ check((pos + this.width - 1) % this.data.length);
+ check((pos + this.width + 1) % this.data.length);
+
+ if (lowerNeighbors.length > 0) {
+ const downhill = lowerNeighbors[this.rng() % lowerNeighbors.length];
+ return this.drop(downhill);
+ }
+
+ // flat, increase elevation
+ const newValue = ++this.data[pos];
+ if (newValue == 9) {
+ this.done = true;
+ }
+ }
+
+ public dropWithin(tiles: number[]) {
+ if (tiles.length > 0) {
+ this.drop(tiles[this.rng() % tiles.length]);
+ }
+ }
+
+ public step() {
+ const lowlandTiles1 = this.floodSearch(this.lobePos1, (tile) => tile > 0);
+ const lowlandTiles2 = this.floodSearch(this.lobePos2, (tile) => tile > 0);
+
+ // grow shore
+ const shoreTiles1 = lowlandTiles1.filter((pos) => this.data[pos] == 0);
+ this.dropWithin(shoreTiles1);
+ const shoreTiles2 = lowlandTiles2.filter((pos) => this.data[pos] == 0);
+ this.dropWithin(shoreTiles2);
+
+ // seed beach
+ const beachTiles = lowlandTiles1.filter((pos) => this.data[pos] == 1);
+ this.dropWithin(beachTiles);
+
+ // expand forest
+ const forestTiles = lowlandTiles1.filter((pos) => this.data[pos] == 2);
+ this.dropWithin(forestTiles);
+ this.dropWithin(forestTiles);
+ this.dropWithin(forestTiles);
+
+ // form mountain
+ const mountainTiles = this.floodSearch(this.basePos, (tile) => tile > 4);
+ this.dropWithin(mountainTiles); // GENERATOR
+
+ // const erodePos = islandTiles[islands.rng() % islandTiles.length];
+ // islands.data[erodePos] = Math.max(islands.data[erodePos] - 1, 0);
+ }
}
function renderIslands(islands: IslandGrid, cx: CanvasRenderingContext2D) {
@@ -109,103 +201,13 @@ export function IslandApplet() {
});
cx.scale(BLOWUP, BLOWUP);
- const seedInput = h("input", { type: "number", valueAsNumber: 128 });
+ const seedInput = h("input", { type: "number", valueAsNumber: DEFAULT_SEED });
const seedLabel = h("label", {}, "Seed:", seedInput);
// STATE
let timerId: number;
- let islands = new IslandGrid(WIDTH, HEIGHT, 128);
-
- // GENERATOR
-
- const len = islands.data.length;
- const basePos = len >> 1;
- const lobePos1 = islands.xy(
- (WIDTH >> 1) + (islands.rng() % 48) - 24,
- (HEIGHT >> 1) + (islands.rng() % 48) - 24
- );
- const lobePos2 = islands.xy(
- (WIDTH >> 1) + (islands.rng() % 48) - 24,
- (HEIGHT >> 1) + (islands.rng() % 48) - 24
- );
- const width = islands.width;
-
- function drop(pos: number) {
- const lowerNeighbors: number[] = [];
-
- function check(adjPos: number) {
- if (islands.data[adjPos] < islands.data[pos]) {
- lowerNeighbors.push(adjPos);
- }
- }
-
- // try to roll in cardinal directions
-
- check((pos - width) % len);
- check((pos - 1) % len);
- check((pos + 1) % len);
- check((pos + width) % len);
-
- if (lowerNeighbors.length > 0) {
- const downhill = lowerNeighbors[islands.rng() % lowerNeighbors.length];
- return drop(downhill);
- }
-
- // try to roll in diagonal directions
-
- check((pos - width - 1) % len);
- check((pos - width + 1) % len);
- check((pos + width - 1) % len);
- check((pos + width + 1) % len);
-
- if (lowerNeighbors.length > 0) {
- const downhill = lowerNeighbors[islands.rng() % lowerNeighbors.length];
- return drop(downhill);
- }
-
- // flat, increase elevation
- const newValue = ++islands.data[pos];
- if (newValue == 9) {
- clearInterval(timerId);
- }
- }
-
- function dropWithin(tiles: number[]) {
- if (tiles.length > 0) {
- drop(tiles[islands.rng() % tiles.length]);
- }
- }
-
- function tick() {
- const lowlandTiles1 = islands.floodSearch(lobePos1, (tile) => tile > 0);
- const lowlandTiles2 = islands.floodSearch(lobePos2, (tile) => tile > 0);
-
- // grow shore
- const shoreTiles1 = lowlandTiles1.filter((pos) => islands.data[pos] == 0);
- dropWithin(shoreTiles1);
- const shoreTiles2 = lowlandTiles2.filter((pos) => islands.data[pos] == 0);
- dropWithin(shoreTiles2);
-
- // seed beach
- const beachTiles = lowlandTiles1.filter((pos) => islands.data[pos] == 1);
- dropWithin(beachTiles);
-
- // expand forest
- const forestTiles = lowlandTiles1.filter((pos) => islands.data[pos] == 2);
- dropWithin(forestTiles);
- dropWithin(forestTiles);
- dropWithin(forestTiles);
-
- // form mountain
- const mountainTiles = islands.floodSearch(basePos, (tile) => tile > 4);
- dropWithin(mountainTiles);
-
- // const erodePos = islandTiles[islands.rng() % islandTiles.length];
- // islands.data[erodePos] = Math.max(islands.data[erodePos] - 1, 0);
-
- renderIslands(islands, cx);
- }
+ let islands = new IslandGrid(WIDTH, HEIGHT, DEFAULT_SEED);
// CONTROLS
@@ -214,9 +216,19 @@ export function IslandApplet() {
{
onclick: () => {
clearInterval(timerId);
- console.log(seedInput.valueAsNumber);
+
islands = new IslandGrid(WIDTH, HEIGHT, seedInput.valueAsNumber);
- timerId = setInterval(tick, 1000 / 30);
+
+ timerId = setInterval(function tick() {
+ islands.step();
+ islands.step();
+ islands.step();
+ if (islands.done) {
+ clearInterval(timerId);
+ }
+
+ renderIslands(islands, cx);
+ }, 1000 / 30);
},
},
"Generate"