1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** Return value for {@linkcode getRowPadding}. */export interface Padding {  /** The number of bytes per row without padding calculated. */  unpadded: number;  /** The number of bytes per row with padding calculated. */  padded: number;}
/** Buffer-Texture copies must have [`bytes_per_row`] aligned to this number. */export const COPY_BYTES_PER_ROW_ALIGNMENT = 256;
/** Number of bytes per pixel. */export const BYTES_PER_PIXEL = 4;
/** * Calculates the number of bytes including necessary padding when passing a {@linkcode GPUImageCopyBuffer}. * * Ref: https://en.wikipedia.org/wiki/Data_structure_alignment#Computing_padding * * @example * ```ts * import { getRowPadding } from "https://deno.land/std@$STD_VERSION/webgpu/row_padding.ts"; * * getRowPadding(2); // { unpadded: 8, padded: 256 } * ``` */export function getRowPadding(width: number): Padding {  // It is a WebGPU requirement that  // GPUImageCopyBuffer.layout.bytesPerRow % COPY_BYTES_PER_ROW_ALIGNMENT == 0  // So we calculate paddedBytesPerRow by rounding unpaddedBytesPerRow  // up to the next multiple of COPY_BYTES_PER_ROW_ALIGNMENT.
  const unpaddedBytesPerRow = width * BYTES_PER_PIXEL;  const paddedBytesPerRowPadding = (COPY_BYTES_PER_ROW_ALIGNMENT -    (unpaddedBytesPerRow % COPY_BYTES_PER_ROW_ALIGNMENT)) %    COPY_BYTES_PER_ROW_ALIGNMENT;  const paddedBytesPerRow = unpaddedBytesPerRow + paddedBytesPerRowPadding;
  return {    unpadded: unpaddedBytesPerRow,    padded: paddedBytesPerRow,  };}
/** * Creates a new buffer while removing any unnecessary empty bytes. * Useful for when wanting to save an image as a specific format. * * @example * ```ts * import { resliceBufferWithPadding } from "https://deno.land/std@$STD_VERSION/webgpu/row_padding.ts"; * * const input = new Uint8Array([0, 255, 0, 255, 120, 120, 120]); * resliceBufferWithPadding(input, 1, 1); // Uint8Array(4) [ 0, 255, 0, 255 ] * ``` */export function resliceBufferWithPadding(  buffer: Uint8Array,  width: number,  height: number,): Uint8Array {  const { padded, unpadded } = getRowPadding(width);  const outputBuffer = new Uint8Array(unpadded * height);
  for (let i = 0; i < height; i++) {    const slice = buffer      .slice(i * padded, (i + 1) * padded)      .slice(0, unpadded);
    outputBuffer.set(slice, i * unpadded);  }
  return outputBuffer;}