Add SkScalarPow.

git-svn-id: http://skia.googlecode.com/svn/trunk@4754 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkFloatingPoint.h

@@ -16,10 +16,11 @@
 #include <float.h>
 #include "SkFloatBits.h"
 
-// If math.h had powf(float, float), I could remove this wrapper
+// C++98 cmath std::pow seems to be the earliest portable way to get float pow.
+// However, on Linux including cmath undefines isfinite.
+// http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14608
 static inline float sk_float_pow(float base, float exp) {
-    return static_cast<float>(pow(static_cast<double>(base),
-                                  static_cast<double>(exp)));
+    return powf(base, exp);
 }
 
 static inline float sk_float_copysign(float x, float y) {

include/core/SkScalar.h

@@ -182,6 +182,9 @@
     /** Returns the square root of the SkScalar
     */
     #define SkScalarSqrt(x)         sk_float_sqrt(x)
+    /** Returns b to the e
+    */
+    #define SkScalarPow(b, e)       sk_float_pow(b, e)
     /** Returns the average of two SkScalars (a+b)/2
     */
     #define SkScalarAve(a, b)       (((a) + (b)) * 0.5f)

src/effects/SkLightingImageFilter.cpp

@@ -23,9 +23,6 @@ class GrGLSpecularLightingEffect;
 typedef GrGLShaderBuilder::UniformHandle UniformHandle;
 static const UniformHandle kInvalidUniformHandle = GrGLShaderBuilder::kInvalidUniformHandle;
 
-// FIXME:  Eventually, this should be implemented properly, and put in
-// SkScalar.h.
-#define SkScalarPow(x, y) SkFloatToScalar(powf(SkScalarToFloat(x), SkScalarToFloat(y)))
 namespace {
 
 const SkScalar gOneThird = SkScalarInvert(SkIntToScalar(3));