fury-js
Version:
WebGL Game Engine
470 lines (434 loc) • 10.9 kB
JavaScript
const { ARRAY_TYPE, EPSILON } = require("./common.js");
/**
* 2x2 Matrix
* @module mat2
*/
/**
* Creates a new identity mat2
*
* @returns {mat2} a new 2x2 matrix
*/
exports.create = function() {
let out = new ARRAY_TYPE(4);
out[1] = 0;
out[2] = 0;
out[0] = 1;
out[3] = 1;
return out;
};
/**
* Creates a new mat2 initialized with values from an existing matrix
*
* @param {ReadonlyMat2} a matrix to clone
* @returns {mat2} a new 2x2 matrix
*/
exports.clone = function(a) {
let out = new ARRAY_TYPE(4);
out[0] = a[0];
out[1] = a[1];
out[2] = a[2];
out[3] = a[3];
return out;
};
/**
* Copy the values from one mat2 to another
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the source matrix
* @returns {mat2} out
*/
exports.copy = function(out, a) {
out[0] = a[0];
out[1] = a[1];
out[2] = a[2];
out[3] = a[3];
return out;
};
/**
* Set a mat2 to the identity matrix
*
* @param {mat2} out the receiving matrix
* @returns {mat2} out
*/
exports.identity = function(out) {
out[0] = 1;
out[1] = 0;
out[2] = 0;
out[3] = 1;
return out;
};
/**
* Create a new mat2 with the given values
*
* @param {Number} m00 Component in column 0, row 0 position (index 0)
* @param {Number} m01 Component in column 0, row 1 position (index 1)
* @param {Number} m10 Component in column 1, row 0 position (index 2)
* @param {Number} m11 Component in column 1, row 1 position (index 3)
* @returns {mat2} out A new 2x2 matrix
*/
exports.fromValues = function(m00, m01, m10, m11) {
let out = new ARRAY_TYPE(4);
out[0] = m00;
out[1] = m01;
out[2] = m10;
out[3] = m11;
return out;
};
/**
* Set the components of a mat2 to the given values
*
* @param {mat2} out the receiving matrix
* @param {Number} m00 Component in column 0, row 0 position (index 0)
* @param {Number} m01 Component in column 0, row 1 position (index 1)
* @param {Number} m10 Component in column 1, row 0 position (index 2)
* @param {Number} m11 Component in column 1, row 1 position (index 3)
* @returns {mat2} out
*/
exports.set = function(out, m00, m01, m10, m11) {
out[0] = m00;
out[1] = m01;
out[2] = m10;
out[3] = m11;
return out;
};
/**
* Transpose the values of a mat2
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the source matrix
* @returns {mat2} out
*/
exports.transpose = function(out, a) {
// If we are transposing ourselves we can skip a few steps but have to cache
// some values
if (out === a) {
let a1 = a[1];
out[1] = a[2];
out[2] = a1;
} else {
out[0] = a[0];
out[1] = a[2];
out[2] = a[1];
out[3] = a[3];
}
return out;
};
/**
* Inverts a mat2
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the source matrix
* @returns {mat2} out
*/
exports.invert = function(out, a) {
let a0 = a[0],
a1 = a[1],
a2 = a[2],
a3 = a[3];
// Calculate the determinant
let det = a0 * a3 - a2 * a1;
if (!det) {
return null;
}
det = 1.0 / det;
out[0] = a3 * det;
out[1] = -a1 * det;
out[2] = -a2 * det;
out[3] = a0 * det;
return out;
};
/**
* Calculates the adjugate of a mat2
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the source matrix
* @returns {mat2} out
*/
exports.adjoint = function(out, a) {
// Caching this value is necessary if out == a
let a0 = a[0];
out[0] = a[3];
out[1] = -a[1];
out[2] = -a[2];
out[3] = a0;
return out;
};
/**
* Calculates the determinant of a mat2
*
* @param {ReadonlyMat2} a the source matrix
* @returns {Number} determinant of a
*/
exports.determinant = function(a) {
return a[0] * a[3] - a[2] * a[1];
};
/**
* Multiplies two mat2's
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the first operand
* @param {ReadonlyMat2} b the second operand
* @returns {mat2} out
*/
exports.multiply = function(out, a, b) {
let a0 = a[0],
a1 = a[1],
a2 = a[2],
a3 = a[3];
let b0 = b[0],
b1 = b[1],
b2 = b[2],
b3 = b[3];
out[0] = a0 * b0 + a2 * b1;
out[1] = a1 * b0 + a3 * b1;
out[2] = a0 * b2 + a2 * b3;
out[3] = a1 * b2 + a3 * b3;
return out;
};
/**
* Rotates a mat2 by the given angle
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the matrix to rotate
* @param {Number} rad the angle to rotate the matrix by
* @returns {mat2} out
*/
exports.rotate = function(out, a, rad) {
let a0 = a[0],
a1 = a[1],
a2 = a[2],
a3 = a[3];
let s = Math.sin(rad);
let c = Math.cos(rad);
out[0] = a0 * c + a2 * s;
out[1] = a1 * c + a3 * s;
out[2] = a0 * -s + a2 * c;
out[3] = a1 * -s + a3 * c;
return out;
};
/**
* Scales the mat2 by the dimensions in the given vec2
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the matrix to rotate
* @param {ReadonlyVec2} v the vec2 to scale the matrix by
* @returns {mat2} out
**/
exports.scale = function(out, a, v) {
let a0 = a[0],
a1 = a[1],
a2 = a[2],
a3 = a[3];
let v0 = v[0],
v1 = v[1];
out[0] = a0 * v0;
out[1] = a1 * v0;
out[2] = a2 * v1;
out[3] = a3 * v1;
return out;
};
/**
* Creates a matrix from a given angle
* This is equivalent to (but much faster than):
*
* mat2.identity(dest);
* mat2.rotate(dest, dest, rad);
*
* @param {mat2} out mat2 receiving operation result
* @param {Number} rad the angle to rotate the matrix by
* @returns {mat2} out
*/
exports.fromRotation = function(out, rad) {
let s = Math.sin(rad);
let c = Math.cos(rad);
out[0] = c;
out[1] = s;
out[2] = -s;
out[3] = c;
return out;
};
/**
* Creates a matrix from a vector scaling
* This is equivalent to (but much faster than):
*
* mat2.identity(dest);
* mat2.scale(dest, dest, vec);
*
* @param {mat2} out mat2 receiving operation result
* @param {ReadonlyVec2} v Scaling vector
* @returns {mat2} out
*/
exports.fromScaling = function(out, v) {
out[0] = v[0];
out[1] = 0;
out[2] = 0;
out[3] = v[1];
return out;
};
/**
* Returns a string representation of a mat2
*
* @param {ReadonlyMat2} a matrix to represent as a string
* @returns {String} string representation of the matrix
*/
exports.str = function(a) {
return "mat2(" + a[0] + ", " + a[1] + ", " + a[2] + ", " + a[3] + ")";
};
/**
* Returns Frobenius norm of a mat2
*
* @param {ReadonlyMat2} a the matrix to calculate Frobenius norm of
* @returns {Number} Frobenius norm
*/
exports.frob = function(a) {
return Math.sqrt(a[0] * a[0] + a[1] * a[1] + a[2] * a[2] + a[3] * a[3]);
};
/**
* Returns L, D and U matrices (Lower triangular, Diagonal and Upper triangular) by factorizing the input matrix
* @param {ReadonlyMat2} L the lower triangular matrix
* @param {ReadonlyMat2} D the diagonal matrix
* @param {ReadonlyMat2} U the upper triangular matrix
* @param {ReadonlyMat2} a the input matrix to factorize
*/
exports.LDU = function(L, D, U, a) {
L[2] = a[2] / a[0];
U[0] = a[0];
U[1] = a[1];
U[3] = a[3] - L[2] * U[1];
return [L, D, U];
};
/**
* Adds two mat2's
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the first operand
* @param {ReadonlyMat2} b the second operand
* @returns {mat2} out
*/
exports.add = function(out, a, b) {
out[0] = a[0] + b[0];
out[1] = a[1] + b[1];
out[2] = a[2] + b[2];
out[3] = a[3] + b[3];
return out;
};
/**
* Subtracts matrix b from matrix a
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the first operand
* @param {ReadonlyMat2} b the second operand
* @returns {mat2} out
*/
exports.subtract = function(out, a, b) {
out[0] = a[0] - b[0];
out[1] = a[1] - b[1];
out[2] = a[2] - b[2];
out[3] = a[3] - b[3];
return out;
};
/**
* Returns whether or not the matrices have exactly the same elements in the same position (when compared with ===)
*
* @param {ReadonlyMat2} a The first matrix.
* @param {ReadonlyMat2} b The second matrix.
* @returns {Boolean} True if the matrices are equal, false otherwise.
*/
exports.exactEquals = function(a, b) {
return a[0] === b[0] && a[1] === b[1] && a[2] === b[2] && a[3] === b[3];
};
/**
* Returns whether or not the matrices have approximately the same elements in the same position.
*
* @param {ReadonlyMat2} a The first matrix.
* @param {ReadonlyMat2} b The second matrix.
* @returns {Boolean} True if the matrices are equal, false otherwise.
*/
exports.equals = function (a, b) {
let a0 = a[0],
a1 = a[1],
a2 = a[2],
a3 = a[3];
let b0 = b[0],
b1 = b[1],
b2 = b[2],
b3 = b[3];
return (
Math.abs(a0 - b0) <=
EPSILON * Math.max(1.0, Math.abs(a0), Math.abs(b0)) &&
Math.abs(a1 - b1) <=
EPSILON * Math.max(1.0, Math.abs(a1), Math.abs(b1)) &&
Math.abs(a2 - b2) <=
EPSILON * Math.max(1.0, Math.abs(a2), Math.abs(b2)) &&
Math.abs(a3 - b3) <=
EPSILON * Math.max(1.0, Math.abs(a3), Math.abs(b3))
);
};
/**
* Multiply each element of the matrix by a scalar.
*
* @param {mat2} out the receiving matrix
* @param {ReadonlyMat2} a the matrix to scale
* @param {Number} b amount to scale the matrix's elements by
* @returns {mat2} out
*/
exports.multiplyScalar = function(out, a, b) {
out[0] = a[0] * b;
out[1] = a[1] * b;
out[2] = a[2] * b;
out[3] = a[3] * b;
return out;
};
/**
* Adds two mat2's after multiplying each element of the second operand by a scalar value.
*
* @param {mat2} out the receiving vector
* @param {ReadonlyMat2} a the first operand
* @param {ReadonlyMat2} b the second operand
* @param {Number} scale the amount to scale b's elements by before adding
* @returns {mat2} out
*/
exports.multiplyScalarAndAdd = function(out, a, b, scale) {
out[0] = a[0] + b[0] * scale;
out[1] = a[1] + b[1] * scale;
out[2] = a[2] + b[2] * scale;
out[3] = a[3] + b[3] * scale;
return out;
};
/**
* Alias for {@link mat2.multiply}
* @function
*/
exports.mul = exports.multiply;
/**
* Alias for {@link mat2.subtract}
* @function
*/
exports.sub = exports.subtract;
/**
* mat2 pool for minimising garbage allocation
*/
exports.Pool = (function(){
let stack = [];
for (let i = 0; i < 5; i++) {
stack.push(exports.create());
}
return {
/**
* return a borrowed mat2 to the pool
* @param {mat2}
*/
return: (v) => { stack.push(exports.identity(v)); },
/**
* request a mat2 from the pool
* @returns {mat2}
*/
request: () => {
if (stack.length > 0) {
return stack.pop();
}
return exports.create();
}
}
})();
exports.IDENTITY = Object.freeze(exports.create());