+// this is a full matrix inverter, it should be able to invert any matrix that
+// is possible to invert
+// (non-uniform scaling, rotation, shearing, and translation, possibly others)
+// warning: this function is SLOW
+int Matrix4x4_Invert_Full (matrix4x4_t *out, const matrix4x4_t *in1);
+// creates a matrix that does the opposite of the matrix provided