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mat3.ts 4.97 KiB
/**
* Copyright (c) 2017-2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
*
* @author David Sehnal <david.sehnal@gmail.com>
* @author Alexander Rose <alexander.rose@weirdbyte.de>
*/
/*
* This code has been modified from https://github.com/toji/gl-matrix/,
* copyright (c) 2015, Brandon Jones, Colin MacKenzie IV.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*/
import { Mat4 } from '../3d'
interface Mat3 extends Array<number> { [d: number]: number, '@type': 'mat3', length: 9 }
namespace Mat3 {
export function zero(): Mat3 {
// force double backing array by 0.1.
const ret = [0.1, 0, 0, 0, 0, 0, 0, 0, 0];
ret[0] = 0.0;
return ret as any;
}
export function identity(): Mat3 {
const out = zero();
out[0] = 1;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 1;
out[5] = 0;
out[6] = 0;
out[7] = 0;
out[8] = 1;
return out;
}
export function setIdentity(mat: Mat3): Mat3 {
mat[0] = 1;
mat[1] = 0;
mat[2] = 0;
mat[3] = 0;
mat[4] = 1;
mat[5] = 0;
mat[6] = 0;
mat[7] = 0;
mat[8] = 1;
return mat;
}
export function toArray(a: Mat3, out: Helpers.NumberArray, offset: number) {
out[offset + 0] = a[0];
out[offset + 1] = a[1];
out[offset + 2] = a[2];
out[offset + 3] = a[3];
out[offset + 4] = a[4];
out[offset + 5] = a[5];
out[offset + 6] = a[6];
out[offset + 7] = a[7];
out[offset + 8] = a[8];
}
export function fromArray(a: Mat3, array: Helpers.NumberArray, offset: number) {
a[0] = array[offset + 0]
a[1] = array[offset + 1]
a[2] = array[offset + 2]
a[3] = array[offset + 3]
a[4] = array[offset + 4]
a[5] = array[offset + 5]
a[6] = array[offset + 6]
a[7] = array[offset + 7]
a[8] = array[offset + 8]
return a
}
/**
* Copies the upper-left 3x3 values into the given mat3.
*/
export function fromMat4(out: Mat3, a: Mat4) {
out[0] = a[0];
out[1] = a[1];
out[2] = a[2];
out[3] = a[4];
out[4] = a[5];
out[5] = a[6];
out[6] = a[8];
out[7] = a[9];
out[8] = a[10];
return out;
}
/**
* Creates a new Mat3 initialized with values from an existing matrix
*/
export function clone(a: Mat3) {
return Mat3.copy(Mat3.zero(), a);
}
/**
* Copy the values from one Mat3 to another
*/
export function copy(out: Mat3, a: Mat3) {
out[0] = a[0];
out[1] = a[1];
out[2] = a[2];
out[3] = a[3];
out[4] = a[4];
out[5] = a[5];
out[6] = a[6];
out[7] = a[7];
out[8] = a[8];
return out;
}
/**
* Transpose the values of a Mat3
*/
export function transpose(out: Mat3, a: Mat3) {
// If we are transposing ourselves we can skip a few steps but have to cache some values
if (out === a) {
const a01 = a[1], a02 = a[2], a12 = a[5];
out[1] = a[3];
out[2] = a[6];
out[3] = a01;
out[5] = a[7];
out[6] = a02;
out[7] = a12;
} else {
out[0] = a[0];
out[1] = a[3];
out[2] = a[6];
out[3] = a[1]; out[4] = a[4];
out[5] = a[7];
out[6] = a[2];
out[7] = a[5];
out[8] = a[8];
}
return out;
}
/**
* Inverts a Mat3
*/
export function invert(out: Mat3, a: Mat3): Mat3 {
const a00 = a[0], a01 = a[1], a02 = a[2];
const a10 = a[3], a11 = a[4], a12 = a[5];
const a20 = a[6], a21 = a[7], a22 = a[8];
const b01 = a22 * a11 - a12 * a21;
const b11 = -a22 * a10 + a12 * a20;
const b21 = a21 * a10 - a11 * a20;
// Calculate the determinant
let det = a00 * b01 + a01 * b11 + a02 * b21;
if (!det) {
console.warn('non-invertible matrix.', a);
return out;
}
det = 1.0 / det;
out[0] = b01 * det;
out[1] = (-a22 * a01 + a02 * a21) * det;
out[2] = (a12 * a01 - a02 * a11) * det;
out[3] = b11 * det;
out[4] = (a22 * a00 - a02 * a20) * det;
out[5] = (-a12 * a00 + a02 * a10) * det;
out[6] = b21 * det;
out[7] = (-a21 * a00 + a01 * a20) * det;
out[8] = (a11 * a00 - a01 * a10) * det;
return out;
}
}
export default Mat3