101 lines
2.7 KiB
JavaScript
101 lines
2.7 KiB
JavaScript
import {createCanvas, drawRect, clipCanvas, drawCircle} from './gfx.js';
|
|
import {coords2index, random, randomInt, clamp} from './math.js';
|
|
import {sample} from './utils.js';
|
|
|
|
let cachedImageData;
|
|
|
|
function cacheImageData(ctx) {
|
|
const {width, height} = ctx.canvas;
|
|
cachedImageData = ctx.getImageData(0, 0, width, height);
|
|
}
|
|
|
|
export function createTerrain(width, height) {
|
|
const terrain = createCanvas(width, height);
|
|
const generateTerrain = sample(Object.values(TERRAIN_TYPES));
|
|
generateTerrain(terrain);
|
|
return terrain;
|
|
}
|
|
|
|
const TERRAIN_TYPES = {
|
|
mountain(ctx) {
|
|
ctx.color = sample(['palegreen', 'white']); // FIXME
|
|
const {width, height} = ctx.canvas;
|
|
const stepCount = 8;
|
|
const stepSize = width / stepCount;
|
|
|
|
let cy = random(.3, .7) * height;
|
|
let dy = 0;
|
|
|
|
for (let x=0; x<width; x++) {
|
|
if (x % stepSize === 0) dy = ((random(.3, .7)*height)-cy)/stepSize;
|
|
if (x % (stepSize/16) === 0) dy = dy - random(-1, 1);
|
|
cy = clamp(0, Math.round(cy + dy), height);
|
|
drawRect(ctx, x, cy, 1, height-cy, ctx.color);
|
|
}
|
|
|
|
cacheImageData(ctx);
|
|
},
|
|
|
|
sand(ctx) {
|
|
ctx.color = 'burlywood'; // FIXME
|
|
const {width, height} = ctx.canvas;
|
|
const stepCount = 16;
|
|
const stepSize = width / stepCount;
|
|
|
|
for (let s=0; s<=stepCount; s++) {
|
|
drawCircle(ctx, s*stepSize, height, randomInt(stepSize, stepSize*2), ctx.color);
|
|
if (s % 3 === 0) drawCircle(ctx, s*stepSize, 0, randomInt(0, stepSize*4), ctx.color);
|
|
}
|
|
|
|
cacheImageData(ctx);
|
|
collapseTerrain(ctx, width/2, width/2);
|
|
}
|
|
};
|
|
|
|
export function collapseTerrain(ctx, ox, r) {
|
|
const {height} = ctx.canvas;
|
|
const width = r * 2 + 10;
|
|
const left = ox-r-5;
|
|
const imageData = ctx.getImageData(left, 0, width, height);
|
|
|
|
for (let x=0; x<width; x++) {
|
|
let land = 0;
|
|
for (let y=0; y<height; y++) {
|
|
const index = y*width*4 + x*4 +3;
|
|
if (imageData.data[index] > 0) land++;
|
|
}
|
|
|
|
ctx.clearRect(left+x, 0, 1, height);
|
|
drawRect(ctx, left+x, height-land, 1, land, ctx.color);
|
|
}
|
|
|
|
cacheImageData(ctx);
|
|
}
|
|
|
|
export function isTerrain(ctx, x, y) {
|
|
const index = coords2index(ctx.canvas.width, x, y) * 4;
|
|
return cachedImageData.data[index+3] > 0;
|
|
}
|
|
|
|
export function closestLand(ctx, x, y) {
|
|
const {width, height} = ctx.canvas;
|
|
for (let i=y; i<height; i++) {
|
|
const index = coords2index(width, x, i) * 4;
|
|
if (cachedImageData.data[index+3] !== 0) return i;
|
|
}
|
|
return height-1;
|
|
}
|
|
|
|
export function landHeight(ctx, x) {
|
|
const {width, height} = ctx.canvas;
|
|
for (let i=height-1; i>=0; i--) {
|
|
const index = coords2index(width, x, i) * 4;
|
|
if (cachedImageData.data[index+3] === 0) return i;
|
|
}
|
|
}
|
|
|
|
export function clipTerrain(ctx, fn) {
|
|
clipCanvas(ctx, fn);
|
|
cacheImageData(ctx);
|
|
}
|