diff -r 767592024ec5 -r 4c41bfe2ec6e src/invert.cpp
--- a/src/invert.cpp	Sun Jan 26 01:06:27 2020 +0200
+++ b/src/invert.cpp	Sun Jan 26 14:29:30 2020 +0200
@@ -18,7 +18,6 @@
 
 #include "main.h"
 #include "model.h"
-#include "matrix.h"
 #include "gl/common.h"
 #include "invert.h"
 
@@ -73,10 +72,11 @@
 /*
  * Returns a matrix that causes a flip on the given dimension.
  */
-Matrix4x4 math::flipmatrix(const Axis dimension)
+glm::mat4 math::flipmatrix(const Axis dimension)
 {
-	Matrix4x4 result = identity4x4;
-	result(static_cast<int>(dimension), static_cast<int>(dimension)) = -1;
+	glm::mat4 result = glm::mat4();
+	const int k = static_cast<int>(dimension);
+	result[k][k] = -1;
 	return result;
 }