plasma_height_map_render.js

// offsets for height maps
// for now, we leave them at upper left corner

let dx1 = 0;
let dy1 = 0;

let dx2 = 0;
let dy2 = 0;

// update our image data array with greyscale values
// as per our height maps
const updateImageData = () => {
  for (let u = 0; u < imgSize; u++) {
    for (let v = 0; v < imgSize; v++) {
      // indexes into height maps for pixel
      const i = (u + dy1) * mapSize + (v + dx1);
      const k = (u + dy2) * mapSize + (v + dx2);

      // index for pixel in image data
      // remember it's 4 bytes per pixel
      const j = u * imgSize * 4 + v * 4;

      // height value of 0..255
      let h = heightMap1[i] + heightMap2[k];

      // greyscale color according to height
      let c = { r: h, g: h, b: h };

      // set pixel data
      image.data[j] = c.r;
      image.data[j + 1] = c.g;
      image.data[j + 2] = c.b;
    }
  }
};