@luma.gl/engine
Version:
3D Engine Components for luma.gl
40 lines • 1.67 kB
JavaScript
// luma.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
/**
* Flip rows (can be used on arrays returned from `Framebuffer.readPixels`)
* https: *stackoverflow.com/questions/41969562/
* how-can-i-flip-the-result-of-webglrenderingcontext-readpixels
* @param param0
*/
export function flipRows(options) {
const { data, width, height, bytesPerPixel = 4, temp } = options;
const bytesPerRow = width * bytesPerPixel;
// make a temp buffer to hold one row
const tempBuffer = temp || new Uint8Array(bytesPerRow);
for (let y = 0; y < height / 2; ++y) {
const topOffset = y * bytesPerRow;
const bottomOffset = (height - y - 1) * bytesPerRow;
// make copy of a row on the top half
tempBuffer.set(data.subarray(topOffset, topOffset + bytesPerRow));
// copy a row from the bottom half to the top
data.copyWithin(topOffset, bottomOffset, bottomOffset + bytesPerRow);
// copy the copy of the top half row to the bottom half
data.set(tempBuffer, bottomOffset);
}
}
export function scalePixels(options) {
const { data, width, height } = options;
const newWidth = Math.round(width / 2);
const newHeight = Math.round(height / 2);
const newData = new Uint8Array(newWidth * newHeight * 4);
for (let y = 0; y < newHeight; y++) {
for (let x = 0; x < newWidth; x++) {
for (let c = 0; c < 4; c++) {
newData[(y * newWidth + x) * 4 + c] = data[(y * 2 * width + x * 2) * 4 + c];
}
}
}
return { data: newData, width: newWidth, height: newHeight };
}
//# sourceMappingURL=pixel-data-utils.js.map