A 2×2 matrix can be constructed as an identity matrix or you can specify the values you'd like entered as floats.

The values of the matrix are stored in such a way that you can access them both by the [] operator, and as member variables.

As variables:

float ImpulsePhysics::Matrix2x2::Determinant() const {
	return asArray[0] * asArray[3] - asArray[1] * asArray[2];
}

As an array:

float ImpulsePhysics::Matrix2x2::Determinant() const {
	return _11 * _22 - _12 * _21;
}

2×2 matrices offer the following functions within their class:

• Transpose
• Determinant
• Inverse
• Adjugate (aka adjoint)

Note that none of these functions will modify the current matrix object, rather they return a new 2×2 matrix with the operation applied.

As part of the ImpulsePhysics::Matrices namespace, you also get access to these utility functions:

• Cut2x2, which 'cuts' a 2×2 matrix out of a 3x3 matrix
• Minor
• Cofactor