@thi.ng/pixel-convolve/normal-map.js

Extensible bitmap image convolution, kernel presets, normal map & image pyramid generation

import { ensureChannel } from "@thi.ng/pixel/checks";
import { FloatBuffer } from "@thi.ng/pixel/float";
import { FLOAT_NORMAL } from "@thi.ng/pixel/format/float-norm";
import { __asVec } from "@thi.ng/pixel/internal/utils";
import { convolveChannel } from "./convolve.js";
const normalMap = (src, opts = {}) => {
  const { channel = 0, step = 0, scale = 1, z = 1 } = opts;
  ensureChannel(src.format, channel);
  const spec = [-1, ...new Array(step).fill(0), 1];
  const [sx, sy] = __asVec(scale);
  const dest = new FloatBuffer(src.width, src.height, FLOAT_NORMAL);
  dest.setChannel(
    0,
    convolveChannel(src, {
      kernel: { spec, size: [step + 2, 1] },
      scale: sx,
      channel
    })
  );
  dest.setChannel(
    1,
    convolveChannel(src, {
      kernel: { spec, size: [1, step + 2] },
      scale: sy,
      channel
    })
  );
  dest.setChannel(2, z);
  return dest;
};
export {
  normalMap
};