diff --git a/src/common/rendering/vulkan/renderer/vk_renderpass.cpp b/src/common/rendering/vulkan/renderer/vk_renderpass.cpp
index 257f35c16d..e445723d09 100644
--- a/src/common/rendering/vulkan/renderer/vk_renderpass.cpp
+++ b/src/common/rendering/vulkan/renderer/vk_renderpass.cpp
@@ -35,6 +35,7 @@
 #include "hw_viewpointuniforms.h"
 #include "v_2ddrawer.h"
 #include "i_specialpaths.h"
+#include "cmdlib.h"
 
 VkRenderPassManager::VkRenderPassManager(VulkanRenderDevice* fb) : fb(fb)
 {
diff --git a/src/common/utility/vectors.h b/src/common/utility/vectors.h
index f392f561fd..ea5cb5250c 100644
--- a/src/common/utility/vectors.h
+++ b/src/common/utility/vectors.h
@@ -44,23 +44,32 @@
 #include <math.h>
 #include <float.h>
 #include <string.h>
+
+// this is needed to properly normalize angles. We cannot do that with compiler provided conversions because they differ too much
 #include "xs_Float.h"
-#include "math/cmath.h"
-#include "basics.h"
-#include "cmdlib.h"
-
-
-#define EQUAL_EPSILON (1/65536.)
 
 // make this a local inline function to avoid any dependencies on other headers and not pollute the global namespace
 namespace pi
 {
 	inline constexpr double pi() { return 3.14159265358979323846; }
-	inline constexpr double pif() { return 3.14159265358979323846f; }
+	inline constexpr float pif() { return 3.14159265358979323846f; }
 }
 
+// optionally use reliable math routines if reproducability across hardware is important., but let this still compile without them.
+#if __has_include("math/cmath.h")
+#include "math/cmath.h"
+#else
+double g_cosdeg(double v) { return cos(v * (pi::pi() / 180.)); }
+double g_sindeg(double v) { return sin(v * (pi::pi() / 180.)); }
+double g_cos(double v) { return cos(v); }
+double g_sin(double v) { return sin(v); }
+double g_sqrt(double v) { return sqrt(v); }
+double g_atan2(double v, double w) { return atan2(v, w); }
+#endif
 
 
+#define EQUAL_EPSILON (1/65536.)
+
 template<class vec_t> struct TVector3;
 template<class vec_t> struct TRotator;
 template<class vec_t> struct TAngle;
@@ -1450,8 +1459,13 @@ public:
 
 	double Tan() const
 	{
+		// use an optimized approach if we have a sine table. If not just call the CRT's tan function.
+#if __has_include("math/cmath.h")
 		const auto bam = BAMs();
 		return g_sinbam(bam) / g_cosbam(bam);
+#else
+		return vec_t(tan(Radians()));
+#endif
 	}
 
 	// This is for calculating vertical velocity. For high pitches the tangent will become too large to be useful.
@@ -1460,9 +1474,11 @@ public:
 		return clamp(Tan(), -max, max);
 	}
 
+	// returns sign of the NORMALIZED angle.
 	int Sgn() const
 	{
-		return ::Sgn(int(BAMs()));
+		auto val = int(BAMs());
+		return (val > 0) - (val < 0);
 	}
 };