fast matrix math library for WebGPU
npm install webgpu-matrix[![NPM Package][npm]][npm-url]
Fast 3d math library for webgpu
``js
import {
vec3,
mat4,
} from 'https://wgpu-matrix.org/dist/0.x/wgpu-matrix.module.js';
const fov = 60 * Math.PI / 180
const aspect = width / height;
const near = 0.1;
const far = 1000;
const perspective = mat4.perspective(fov, aspect, near, far);
const eye = [3, 5, 10];
const target = [0, 4, 0];
const up = [0, 1, 0];
const camera = mat4.lookAt(eye, target, up);
const view = mat4.inverse(camera);
`
Note: for translation, rotation, and scaling there are 2 versions
of each function. One generates a translation, rotation, or scaling matrix.
The other translates, rotates, or scales a matrix.
`js`
const t = mat4.translation([1, 2, 3]); // a translation matrix
const r = mat4.rotationX(Math.PI * 0.5); // a rotation matrix
const s = mat4.scaling([1, 2, 3]); // a scaling matrix
`js`
const m = mat4.identity();
const t = mat4.translate(m, [1, 2, 3]); // m * translation([1, 2, 3])
const r = mat4.rotateX(m, Math.PI 0.5); // m rotationX(Math.PI * 0.5)
const s = mat4.scale(m, [1, 2, 3]); // m * scaling([1, 2, 3])
Functions take an optional destination to hold the result.
`js`
const m = mat4.identity();
mat4.translate(m, [1, 2, 3], m); // m = m * translation([1, 2, 3])
mat4.rotateX(m, Math.PI 0.5, m); // m = m rotationX(Math.PI * 0.5)
mat4.scale(m, [1, 2, 3], m); // m = m * scaling([1, 2, 3])
There is also the minified version
`js
import {
vec3,
mat4,
} from 'https://wgpu-matrix.org/dist/0.x/wgpu-matrix.module.min.js';
// ... etc ...
`
or via npm
`sh`
npm install --save wgpu-matrix
then using a build process
`js
import {vec3, mat3} from 'wgpu-matrix';
// ... etc ...
`
mat4.perspective,
mat4.ortho, and
mat4.frustum
all return matrices with Z clip space from 0 to 1 (unlike most WebGL matrix libraries which return -1 to 1)
mat4.lookAt
returns a matrix that makes an object look down the -Z axis. If you want
a view matrix take its inverse.
mat3 uses the space of 12 elements
`js`
// a mat3
[
xx, xy, xz, ?
yx, yy, yz, ?
zx, zy, zz, ?
]
This is because WebGPU requires mat3s to be in this format and since
this library is for WebGPU it makes sense to match so you can manipulate
mat3s in TypeArrays directly.
vec3 in this library uses 3 floats per but be aware that an array ofvec3 in a Uniform Block or other structure in WGSL, each vec3 is
padded to 4 floats! In other words, if you declare
`wgsl`
struct Foo {
bar: vec3
};
then bar[0] is at byte offset 0, bar[1] at byte offset 16, bar[2] at byte offset 32.
See the WGSL spec on alignment and size.
WebGPU follows the same conventions as OpenGL, Vulkan, Metal for matrices. Some people call this "column major". The issue is the columns of
a traditional "math" matrix are stored as rows when declaring a matrix in code.
`js`
[
x1, x2, x3, x4, // <- column 0
y1, y2, y3, y4, // <- column 1
z1, z2, z3, z4, // <- column 2
w1, w2, w3, w4, // <- column 3
]
To put it another way, the translation vector is in elements 12, 13, 14
`js`
[
xx, xy, xz, 0, // <- x-axis
yx, yy, yz, 0, // <- y-axis
zx, zy, zz, 0, // <- z-axis
tx, ty, tz, 1, // <- translation
]
This issue has confused programmers since at least the early 90s 😌
Most functions take an optional destination as the last argument.
If you don't supply it a new one (vector, matrix) will be created
for you.
`js
// convenient usage
const persp = mat4.perspective(fov, aspect, near, far);
const camera = mat4.target(eye, target, up);
const view = mat4.inverse(camera);
`
`js
// performant usage
const persp = mat4.create();
const camera = mat4.create();
const view = mat4.create();
mat4.perspective(fov, aspect, near, far, persp);
mat4.target(eye, target, up, camera);
mat4.inverse(camera, view);
`
For me, most of the stuff I do in WebGPU, the supposed performance I might lose
from using the convenient style is so small as to be unmeasurable. I'd prefer to
stay convenient and then, if and only if I find a performance issue, then I
might bother to switch to the performant style.
As the saying goes premature optimization is the root of all evil. 😉
`sh`
git clone https://github.com/greggman/wgpu-matrix.git
cd wgpu-matrix
npm i
npm run build
npm test
You can run tests in the browser by starting a local server
`sh`
npx servez
Now go to wherever your server serves pages. In the case of servez that's
probably http://localhost:8080/test/.
By default the tests test the minified version. To test the source use src=true
as in http://localhost:8080/test/?src=true.
To limit which tests are run use grep=. For examplemat3
http://localhost:8080/test/?src=true&grep=mat3.?translate
runs only tests with followed by translate` in the name of test.
[npm]: https://img.shields.io/npm/v/wgpu-matrix
[npm-url]: https://www.npmjs.com/package/wgpu-matrix