diff --git a/include/Nazara/Math/Algorithm.hpp b/include/Nazara/Math/Algorithm.hpp
index 070d048aa..0d0776746 100644
--- a/include/Nazara/Math/Algorithm.hpp
+++ b/include/Nazara/Math/Algorithm.hpp
@@ -16,6 +16,10 @@
 #define M_PI 3.141592653589793238462643
 #endif
 
+#ifndef M_PI_2
+#define M_PI_2  1.5707963267948966192313217
+#endif
+
 #ifndef M_SQRT2
 #define M_SQRT2 1.4142135623730950488016887
 #endif
diff --git a/include/Nazara/Math/Matrix4.inl b/include/Nazara/Math/Matrix4.inl
index 694ef446a..6816bbd72 100644
--- a/include/Nazara/Math/Matrix4.inl
+++ b/include/Nazara/Math/Matrix4.inl
@@ -623,7 +623,7 @@ NzMatrix4<T>& NzMatrix4<T>::MakePerspective(T angle, T ratio, T zNear, T zFar)
 	angle = NzDegreeToRadian(angle/F(2.0));
 	#endif
 
-	T yScale = F(1.0) / std::tan(angle);
+	T yScale = std::tan(M_PI_2 - angle);
 
 	Set(yScale / ratio, F(0.0), F(0.0), F(0.0),
 	    F(0.0), yScale, F(0.0), F(0.0),