From 71035db795cc1f3953834948e7ad1fa858e95cf1 Mon Sep 17 00:00:00 2001
From: Christophe Riccio <mail@g-truc.net>
Date: Sat, 28 Dec 2013 03:45:18 +0100
Subject: [PATCH] Added ULP comparison between lowp and highp for inversesqrt

---
 test/core/core_func_exponential.cpp | 30 +++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/test/core/core_func_exponential.cpp b/test/core/core_func_exponential.cpp
index df83f67e..174e164f 100644
--- a/test/core/core_func_exponential.cpp
+++ b/test/core/core_func_exponential.cpp
@@ -7,12 +7,38 @@
 // File    : test/core/func_exponential.cpp
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
+#include <glm/common.hpp>
 #include <glm/exponential.hpp>
+#include <glm/gtc/ulp.hpp>
+
+namespace inversesqrt
+{
+	int test()
+	{
+		int Error(0);
+
+		glm::uint ulp(0);
+		float diff(0.0f);
+
+		for(float f = 0.001f; f < 10.f; f *= 1.001f)
+		{
+			glm::lowp_fvec1 lowp_v = glm::inversesqrt(glm::lowp_fvec1(f));
+			float defaultp_v = glm::inversesqrt(f);
+
+			ulp = glm::max(glm::float_distance(lowp_v.x, defaultp_v), ulp);
+			diff = glm::abs(lowp_v.x - defaultp_v);
+		}
+
+		return Error;
+	}
+}//namespace inversesqrt
 
 int main()
 {
-	int Failed = 0;
+	int Error(0);
+
+	Error += inversesqrt::test();
 
-	return Failed;
+	return Error;
 }