performance test for glm::fastCos

test/gtx/gtx_fast_trigonometry.cpp

@@ -9,10 +9,36 @@
 
 #include <glm/gtc/type_precision.hpp>
 #include <glm/gtx/fast_trigonometry.hpp>
+#include <ctime>
+#include <cstdio>
+
+namespace fastCos{
+	int perf()
+	{
+		const float begin = -glm::pi<float>();
+		const float end = glm::pi<float>();
+		float result = 0.f;
+		const std::clock_t timestamp1 = std::clock();
+		for(float i=begin; i<end; i = nextafterf(i, end))
+			result = glm::fastCos(i);
+		const std::clock_t timestamp2 = std::clock();
+		for(float i=begin; i<end; i = nextafterf(i, end))
+			result = glm::cos(i);
+		const std::clock_t timestamp3 = std::clock();
+		const std::clock_t time_fastCos = timestamp2 - timestamp1;
+		const std::clock_t time_cos = timestamp3 - timestamp2;
+		std::printf("fastCos Time %d clocks\n", static_cast<unsigned int>(time_fastCos));
+		std::printf("cos Time %d clocks\n", static_cast<unsigned int>(time_cos));
+		return time_fastCos < time_cos ? 0 : 1;
+	}
+}
+
 
 int main()
 {
 	int Error(0);
 
+	Error += ::fastCos::perf();
+
 	return Error;
 }