@smoud/tiny/src/math/Mat3.js

Fast and tiny JavaScript library for HTML5 game and playable ads creation.

import { Vec2 } from './Vec2';

var Mat3 = function () {
    this.a = 1;

    this.b = 0;

    this.c = 0;

    this.d = 1;

    this.tx = 0;

    this.ty = 0;
};

Mat3.prototype.fromArray = function (array) {
    this.a = array[0];
    this.b = array[1];
    this.c = array[3];
    this.d = array[4];
    this.tx = array[2];
    this.ty = array[5];
};

Mat3.prototype.toArray = function (transpose) {
    if (!this.array) {
        this.array = new Float32Array(9);
    }

    var array = this.array;

    if (transpose) {
        array[0] = this.a;
        array[1] = this.b;
        array[2] = 0;
        array[3] = this.c;
        array[4] = this.d;
        array[5] = 0;
        array[6] = this.tx;
        array[7] = this.ty;
        array[8] = 1;
    } else {
        array[0] = this.a;
        array[1] = this.c;
        array[2] = this.tx;
        array[3] = this.b;
        array[4] = this.d;
        array[5] = this.ty;
        array[6] = 0;
        array[7] = 0;
        array[8] = 1;
    }

    return array;
};

Mat3.prototype.apply = function (pos, newPos) {
    newPos = newPos || new Vec2();

    var x = pos.x;
    var y = pos.y;

    newPos.x = this.a * x + this.c * y + this.tx;
    newPos.y = this.b * x + this.d * y + this.ty;

    return newPos;
};

Mat3.prototype.applyInverse = function (pos, newPos) {
    newPos = newPos || new Vec2();

    var id = 1 / (this.a * this.d + this.c * -this.b);
    var x = pos.x;
    var y = pos.y;

    newPos.x = this.d * id * x + -this.c * id * y + (this.ty * this.c - this.tx * this.d) * id;
    newPos.y = this.a * id * y + -this.b * id * x + (-this.ty * this.a + this.tx * this.b) * id;

    return newPos;
};

Mat3.prototype.translate = function (x, y) {
    this.tx += x;
    this.ty += y;

    return this;
};

Mat3.prototype.scale = function (x, y) {
    this.a *= x;
    this.d *= y;
    this.c *= x;
    this.b *= y;
    this.tx *= x;
    this.ty *= y;

    return this;
};

Mat3.prototype.rotate = function (angle) {
    var cos = Math.cos(angle);
    var sin = Math.sin(angle);

    var a1 = this.a;
    var c1 = this.c;
    var tx1 = this.tx;

    this.a = a1 * cos - this.b * sin;
    this.b = a1 * sin + this.b * cos;
    this.c = c1 * cos - this.d * sin;
    this.d = c1 * sin + this.d * cos;
    this.tx = tx1 * cos - this.ty * sin;
    this.ty = tx1 * sin + this.ty * cos;

    return this;
};

Mat3.prototype.append = function (matrix) {
    var a1 = this.a;
    var b1 = this.b;
    var c1 = this.c;
    var d1 = this.d;

    this.a = matrix.a * a1 + matrix.b * c1;
    this.b = matrix.a * b1 + matrix.b * d1;
    this.c = matrix.c * a1 + matrix.d * c1;
    this.d = matrix.c * b1 + matrix.d * d1;

    this.tx = matrix.tx * a1 + matrix.ty * c1 + this.tx;
    this.ty = matrix.tx * b1 + matrix.ty * d1 + this.ty;

    return this;
};

Mat3.prototype.identity = function () {
    this.a = 1;
    this.b = 0;
    this.c = 0;
    this.d = 1;
    this.tx = 0;
    this.ty = 0;

    return this;
};

var identityMatrix = new Mat3();

export { Mat3, identityMatrix };