Add FastMath utility header

src/core/math/FastMath.hpp

@@ -0,0 +1,60 @@
+#ifndef FASTMATH_HPP_
+#define FASTMATH_HPP_
+
+#include "Vec.hpp"
+
+#include "sse/SimdFloat.hpp"
+
+#include <fmath/fmath.hpp>
+
+namespace Tungsten {
+
+namespace FastMath {
+
+static inline float exp(float f)
+{
+    return fmath::exp(f);
+}
+static inline Vec2f exp(Vec2f f)
+{
+    float4 result = fmath::exp_ps(float4(f[0], f[1], 0.0f, 0.0f).raw());
+    return Vec2f(result[0], result[1]);
+}
+static inline Vec3f exp(Vec3f f)
+{
+    float4 result = fmath::exp_ps(float4(f[0], f[1], f[2], 0.0f).raw());
+    return Vec3f(result[0], result[1], result[2]);
+}
+static inline Vec4f exp(Vec4f f)
+{
+    float4 result = fmath::exp_ps(float4(f[0], f[1], f[2], f[3]).raw());
+    return Vec4f(result[0], result[1], result[2], result[3]);
+}
+
+static inline float log(float f)
+{
+    return fmath::log(f);
+}
+static inline Vec2f log(Vec2f f)
+{
+    float4 result = fmath::log_ps(float4(f[0], f[1], 0.0f, 0.0f).raw());
+    return Vec2f(result[0], result[1]);
+}
+static inline Vec3f log(Vec3f f)
+{
+    float4 result = fmath::log_ps(float4(f[0], f[1], f[2], 0.0f).raw());
+    return Vec3f(result[0], result[1], result[2]);
+}
+static inline Vec4f log(Vec4f f)
+{
+    float4 result = fmath::log_ps(float4(f[0], f[1], f[2], f[3]).raw());
+    return Vec4f(result[0], result[1], result[2], result[3]);
+}
+
+}
+
+}
+
+
+
+#endif /* FASTMATH_HPP_ */

src/core/media/HomogeneousMedium.cpp

@@ -3,6 +3,7 @@
 #include "sampling/PathSampleGenerator.hpp"
 
 #include "math/TangentFrame.hpp"
+#include "math/FastMath.hpp"
 #include "math/Ray.hpp"
 
 #include "io/JsonObject.hpp"
@@ -73,7 +74,7 @@ bool HomogeneousMedium::sampleDistance(PathSampleGenerator &sampler, const Ray &
         if (maxT == Ray::infinity())
             return false;
         sample.t = maxT;
-        sample.weight = std::exp(-_sigmaT*maxT);
+        sample.weight = FastMath::exp(-_sigmaT*maxT);
         sample.pdf = 1.0f;
         sample.exited = true;
     } else {
@@ -82,7 +83,7 @@ bool HomogeneousMedium::sampleDistance(PathSampleGenerator &sampler, const Ray &
 
         float t = -std::log(1.0f - sampler.next1D())/sigmaTc;
         sample.t = min(t, maxT);
-        sample.weight = std::exp(-sample.t*_sigmaT);
+        sample.weight = FastMath::exp(-sample.t*_sigmaT);
         sample.exited = (t >= maxT);
         if (sample.exited) {
             sample.pdf = sample.weight.avg();
@@ -131,7 +132,7 @@ Vec3f HomogeneousMedium::transmittance(PathSampleGenerator &/*sampler*/, const R
     if (ray.farT() == Ray::infinity())
         return Vec3f(0.0f);
     else {
-        return std::exp(-_sigmaT*ray.farT());
+        return FastMath::exp(-_sigmaT*ray.farT());
     }
 }
 
@@ -141,9 +142,9 @@ float HomogeneousMedium::pdf(PathSampleGenerator &/*sampler*/, const Ray &ray, b
         return 1.0f;
     } else {
         if (onSurface)
-            return std::exp(-ray.farT()*_sigmaT).avg();
+            return FastMath::exp(-ray.farT()*_sigmaT).avg();
         else
-            return (_sigmaT*std::exp(-ray.farT()*_sigmaT)).avg();
+            return (_sigmaT*FastMath::exp(-ray.farT()*_sigmaT)).avg();
     }
 }
 
@@ -155,9 +156,9 @@ Vec3f HomogeneousMedium::transmittanceAndPdfs(PathSampleGenerator &/*sampler*/,
         return Vec3f(0.0f);
     } else if (_absorptionOnly) {
         pdfForward = pdfBackward = 1.0f;
-        return std::exp(-_sigmaT*ray.farT());
+        return FastMath::exp(-_sigmaT*ray.farT());
     } else {
-        Vec3f weight = std::exp(-_sigmaT*ray.farT());
+        Vec3f weight = FastMath::exp(-_sigmaT*ray.farT());
         pdfForward  =   endOnSurface ? weight.avg() : (_sigmaT*weight).avg();
         pdfBackward = startOnSurface ? weight.avg() : (_sigmaT*weight).avg();
         return weight;