tentone.escher.js/source/math/Matrix3.js

"use strict";

function Matrix3()
{
	this.elements = [
		1, 0, 0,
		0, 1, 0,
		0, 0, 1
	];
}

Object.assign(Matrix3.prototype,
{
	isMatrix3: true,

	set: function(n11, n12, n13, n21, n22, n23, n31, n32, n33)
	{
		var te = this.elements;

		te[0] = n11;
		te[1] = n21;
		te[2] = n31;
		te[3] = n12;
		te[4] = n22;
		te[5] = n32;
		te[6] = n13;
		te[7] = n23;
		te[8] = n33;
	},

	identity: function()
	{
		this.set(
			1, 0, 0,
			0, 1, 0,
			0, 0, 1
		);
	},

	clone: function()
	{
		var m = new Matrix3();
		m.fromArray(this.elements);
		return m;
	},

	copy: function(m)
	{
		var te = this.elements;
		var me = m.elements;

		te[0] = me[0];
		te[1] = me[1];
		te[2] = me[2];
		te[3] = me[3];
		te[4] = me[4];
		te[5] = me[5];
		te[6] = me[6];
		te[7] = me[7];
		te[8] = me[8];
	},

	multiply: function(m)
	{
		return this.multiplyMatrices(this, m);
	},

	premultiply: function(m)
	{
		return this.multiplyMatrices(m, this);
	},

	multiplyMatrices: function(a, b)
	{
		var ae = a.elements;
		var be = b.elements;
		var te = this.elements;

		var a11 = ae[0],
			a12 = ae[3],
			a13 = ae[6];
		var a21 = ae[1],
			a22 = ae[4],
			a23 = ae[7];
		var a31 = ae[2],
			a32 = ae[5],
			a33 = ae[8];

		var b11 = be[0],
			b12 = be[3],
			b13 = be[6];
		var b21 = be[1],
			b22 = be[4],
			b23 = be[7];
		var b31 = be[2],
			b32 = be[5],
			b33 = be[8];

		te[0] = a11 * b11 + a12 * b21 + a13 * b31;
		te[3] = a11 * b12 + a12 * b22 + a13 * b32;
		te[6] = a11 * b13 + a12 * b23 + a13 * b33;

		te[1] = a21 * b11 + a22 * b21 + a23 * b31;
		te[4] = a21 * b12 + a22 * b22 + a23 * b32;
		te[7] = a21 * b13 + a22 * b23 + a23 * b33;

		te[2] = a31 * b11 + a32 * b21 + a33 * b31;
		te[5] = a31 * b12 + a32 * b22 + a33 * b32;
		te[8] = a31 * b13 + a32 * b23 + a33 * b33;
	},

	multiplyScalar: function(s)
	{
		var te = this.elements;

		te[0] *= s;
		te[3] *= s;
		te[6] *= s;
		te[1] *= s;
		te[4] *= s;
		te[7] *= s;
		te[2] *= s;
		te[5] *= s;
		te[8] *= s;
	},

	determinant: function()
	{
		var te = this.elements;

		var a = te[0],
			b = te[1],
			c = te[2],
			d = te[3],
			e = te[4],
			f = te[5],
			g = te[6],
			h = te[7],
			i = te[8];

		return a * e * i - a * f * h - b * d * i + b * f * g + c * d * h - c * e * g;
	},

	getInverse: function(matrix, throwOnDegenerate)
	{
		var me = matrix.elements,
			te = this.elements,

			n11 = me[0],
			n21 = me[1],
			n31 = me[2],
			n12 = me[3],
			n22 = me[4],
			n32 = me[5],
			n13 = me[6],
			n23 = me[7],
			n33 = me[8],

			t11 = n33 * n22 - n32 * n23,
			t12 = n32 * n13 - n33 * n12,
			t13 = n23 * n12 - n22 * n13,

			det = n11 * t11 + n21 * t12 + n31 * t13;

		if(det === 0)
		{
			if(throwOnDegenerate === true)
			{
				throw new Error(".getInverse() cant invert matrix, determinant is 0");
			}

			return this.identity();
		}

		var detInv = 1 / det;

		te[0] = t11 * detInv;
		te[1] = (n31 * n23 - n33 * n21) * detInv;
		te[2] = (n32 * n21 - n31 * n22) * detInv;

		te[3] = t12 * detInv;
		te[4] = (n33 * n11 - n31 * n13) * detInv;
		te[5] = (n31 * n12 - n32 * n11) * detInv;

		te[6] = t13 * detInv;
		te[7] = (n21 * n13 - n23 * n11) * detInv;
		te[8] = (n22 * n11 - n21 * n12) * detInv;
	},

	transpose: function()
	{
		var tmp, m = this.elements;

		tmp = m[1];
		m[1] = m[3];
		m[3] = tmp;
		tmp = m[2];
		m[2] = m[6];
		m[6] = tmp;
		tmp = m[5];
		m[5] = m[7];
		m[7] = tmp;
	},

	getNormalMatrix: function(matrix4)
	{
		return this.setFromMatrix4(matrix4).getInverse(this).transpose();
	},

	transposeIntoArray: function(r)
	{
		var m = this.elements;

		r[0] = m[0];
		r[1] = m[3];
		r[2] = m[6];
		r[3] = m[1];
		r[4] = m[4];
		r[5] = m[7];
		r[6] = m[2];
		r[7] = m[5];
		r[8] = m[8];
	},

	setUvTransform: function(tx, ty, sx, sy, rotation, cx, cy)
	{
		var c = Math.cos(rotation);
		var s = Math.sin(rotation);

		this.set(
			sx * c, sx * s, -sx * (c * cx + s * cy) + cx + tx,
			-sy * s, sy * c, -sy * (-s * cx + c * cy) + cy + ty,
			0, 0, 1
		);
	},

	scale: function(sx, sy)
	{
		var te = this.elements;

		te[0] *= sx;
		te[3] *= sx;
		te[6] *= sx;
		te[1] *= sy;
		te[4] *= sy;
		te[7] *= sy;
	},

	rotate: function(theta)
	{
		var c = Math.cos(theta);
		var s = Math.sin(theta);

		var te = this.elements;

		var a11 = te[0],
			a12 = te[3],
			a13 = te[6];
		var a21 = te[1],
			a22 = te[4],
			a23 = te[7];

		te[0] = c * a11 + s * a21;
		te[3] = c * a12 + s * a22;
		te[6] = c * a13 + s * a23;

		te[1] = -s * a11 + c * a21;
		te[4] = -s * a12 + c * a22;
		te[7] = -s * a13 + c * a23;
	},

	translate: function(tx, ty)
	{
		var te = this.elements;

		te[0] += tx * te[2];
		te[3] += tx * te[5];
		te[6] += tx * te[8];
		te[1] += ty * te[2];
		te[4] += ty * te[5];
		te[7] += ty * te[8];
	},

	equals: function(matrix)
	{
		var te = this.elements;
		var me = matrix.elements;

		for(var i = 0; i < 9; i++)
		{

			if(te[i] !== me[i]) return false;

		}

		return true;
	},

	fromArray: function(array, offset)
	{
		if(offset === undefined) offset = 0;

		for(var i = 0; i < 9; i++)
		{
			this.elements[i] = array[i + offset];
		}
	},

	toArray: function(array, offset)
	{
		if(array === undefined) array = [];
		if(offset === undefined) offset = 0;

		var te = this.elements;

		array[offset] = te[0];
		array[offset + 1] = te[1];
		array[offset + 2] = te[2];

		array[offset + 3] = te[3];
		array[offset + 4] = te[4];
		array[offset + 5] = te[5];

		array[offset + 6] = te[6];
		array[offset + 7] = te[7];
		array[offset + 8] = te[8];

		return array;
	}
});

export {Matrix3};