162 lines
4.7 KiB
JavaScript
162 lines
4.7 KiB
JavaScript
import vec2 from './vec2';
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import { epsilon } from './constants';
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export default class mat2 {
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constructor(values) {
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this.values = new Float32Array(4);
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if (values !== undefined) {
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this.init(values);
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}
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}
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at(index) {
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return this.values[index];
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}
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init(values) {
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for (let i = 0; i < 4; i++) {
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this.values[i] = values[i];
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}
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return this;
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}
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reset() {
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for (let i = 0; i < 4; i++) {
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this.values[i] = 0;
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}
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}
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copy(dest) {
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if (!dest) {
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dest = new mat2();
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}
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for (let i = 0; i < 4; i++) {
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dest.values[i] = this.values[i];
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}
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return dest;
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}
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all() {
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const data = [];
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for (let i = 0; i < 4; i++) {
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data[i] = this.values[i];
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}
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return data;
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}
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row(index) {
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return [this.values[index * 2 + 0], this.values[index * 2 + 1]];
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}
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col(index) {
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return [this.values[index], this.values[index + 2]];
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}
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equals(matrix, threshold = epsilon) {
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for (let i = 0; i < 4; i++) {
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if (Math.abs(this.values[i] - matrix.at(i)) > threshold) {
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return false;
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}
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}
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return true;
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}
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determinant() {
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return this.values[0] * this.values[3] - this.values[2] * this.values[1];
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}
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setIdentity() {
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this.values[0] = 1;
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this.values[1] = 0;
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this.values[2] = 0;
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this.values[3] = 1;
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return this;
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}
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transpose() {
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const temp = this.values[1];
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this.values[1] = this.values[2];
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this.values[2] = temp;
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return this;
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}
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inverse() {
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let det = this.determinant();
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if (!det) {
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return null;
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}
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det = 1.0 / det;
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const a11 = this.values[0];
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this.values[0] = det * this.values[3];
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this.values[1] = det * -this.values[1];
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this.values[2] = det * -this.values[2];
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this.values[3] = det * a11;
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return this;
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}
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multiply(matrix) {
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const a11 = this.values[0];
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const a12 = this.values[1];
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const a21 = this.values[2];
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const a22 = this.values[3];
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this.values[0] = a11 * matrix.at(0) + a12 * matrix.at(2);
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this.values[1] = a11 * matrix.at(1) + a12 * matrix.at(3);
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this.values[2] = a21 * matrix.at(0) + a22 * matrix.at(2);
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this.values[3] = a21 * matrix.at(1) + a22 * matrix.at(3);
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return this;
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}
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rotate(angle) {
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const a11 = this.values[0];
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const a12 = this.values[1];
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const a21 = this.values[2];
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const a22 = this.values[3];
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const sin = Math.sin(angle);
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const cos = Math.cos(angle);
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this.values[0] = a11 * cos + a12 * sin;
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this.values[1] = a11 * -sin + a12 * cos;
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this.values[2] = a21 * cos + a22 * sin;
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this.values[3] = a21 * -sin + a22 * cos;
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return this;
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}
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multiplyVec2(vector, result) {
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const x = vector.x;
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const y = vector.y;
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if (result) {
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result.xy = [
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x * this.values[0] + y * this.values[1],
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x * this.values[2] + y * this.values[3]
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];
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return result;
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}
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else {
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return new vec2([
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x * this.values[0] + y * this.values[1],
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x * this.values[2] + y * this.values[3]
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]);
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}
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}
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scale(vector) {
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const a11 = this.values[0];
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const a12 = this.values[1];
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const a21 = this.values[2];
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const a22 = this.values[3];
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const x = vector.x;
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const y = vector.y;
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this.values[0] = a11 * x;
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this.values[1] = a12 * y;
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this.values[2] = a21 * x;
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this.values[3] = a22 * y;
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return this;
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}
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static product(m1, m2, result) {
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const a11 = m1.at(0);
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const a12 = m1.at(1);
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const a21 = m1.at(2);
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const a22 = m1.at(3);
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if (result) {
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result.init([
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a11 * m2.at(0) + a12 * m2.at(2),
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a11 * m2.at(1) + a12 * m2.at(3),
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a21 * m2.at(0) + a22 * m2.at(2),
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a21 * m2.at(1) + a22 * m2.at(3)
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]);
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return result;
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}
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else {
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return new mat2([
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a11 * m2.at(0) + a12 * m2.at(2),
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a11 * m2.at(1) + a12 * m2.at(3),
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a21 * m2.at(0) + a22 * m2.at(2),
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a21 * m2.at(1) + a22 * m2.at(3)
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]);
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}
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}
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}
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mat2.identity = new mat2().setIdentity();
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