public static void SkewMatrix(ref Matrix4x4 matrix, float skewX, float skewY)
{
skewX = -skewX * Mathf.Deg2Rad;
skewY = -skewY * Mathf.Deg2Rad;
float sinX = Mathf.Sin(skewX);
float cosX = Mathf.Cos(skewX);
float sinY = Mathf.Sin(skewY);
float cosY = Mathf.Cos(skewY);
float m00 = matrix.m00 * cosY - matrix.m10 * sinX;
float m10 = matrix.m00 * sinY + matrix.m10 * cosX;
float m01 = matrix.m01 * cosY - matrix.m11 * sinX;
float m11 = matrix.m01 * sinY + matrix.m11 * cosX;
float m02 = matrix.m02 * cosY - matrix.m12 * sinX;
float m12 = matrix.m02 * sinY + matrix.m12 * cosX;
matrix.m00 = m00;
matrix.m10 = m10;
matrix.m01 = m01;
matrix.m11 = m11;
matrix.m02 = m02;
matrix.m12 = m12;
}