diff --git a/sprout/darkroom/coords/vector.hpp b/sprout/darkroom/coords/vector.hpp
index 0b5c24fb..a6952b19 100644
--- a/sprout/darkroom/coords/vector.hpp
+++ b/sprout/darkroom/coords/vector.hpp
@@ -171,18 +171,6 @@ namespace sprout {
 					sprout::darkroom::coords::scale(nor, sprout::darkroom::coords::dot(incid, nor) * 2)
 					);
 			}
-
-			//
-			// normal_to_color
-			//
-			template<typename Color, typename Normal>
-			inline SPROUT_CONSTEXPR Color normal_to_color(Normal const& nor) {
-				return sprout::tuples::make<Color>(
-					0.5 + sprout::darkroom::coords::x(nor) * 0.5,
-					0.5 + sprout::darkroom::coords::y(nor) * 0.5,
-					0.5 + sprout::darkroom::coords::z(nor) * 0.5
-					);
-			}
 		}	// namespace coords
 	}	// namespace darkroom
 }	// namespace sprout
diff --git a/sprout/darkroom/materials/interpolation.hpp b/sprout/darkroom/materials/interpolation.hpp
index 386b8eaa..81715bcf 100644
--- a/sprout/darkroom/materials/interpolation.hpp
+++ b/sprout/darkroom/materials/interpolation.hpp
@@ -32,17 +32,17 @@ namespace sprout {
 				return sprout::darkroom::colors::add(
 					sprout::darkroom::colors::mul(
 						sprout::darkroom::colors::add(
-							sprout::darkroom::colors::mul(c00, u),
-							sprout::darkroom::colors::mul(c01, 1 - u)
+							sprout::darkroom::colors::mul(c00, 1 - u),
+							sprout::darkroom::colors::mul(c01, u)
 							),
-						v
+						1 - v
 						),
 					sprout::darkroom::colors::mul(
 						sprout::darkroom::colors::add(
-							sprout::darkroom::colors::mul(c10, u),
-							sprout::darkroom::colors::mul(c11, 1 - u)
+							sprout::darkroom::colors::mul(c10, 1 - u),
+							sprout::darkroom::colors::mul(c11, u)
 							),
-						1 - v
+						v
 						)
 					);
 			}
diff --git a/sprout/darkroom/materials/texture_map.hpp b/sprout/darkroom/materials/texture_map.hpp
index d1ffcb72..342e27c4 100644
--- a/sprout/darkroom/materials/texture_map.hpp
+++ b/sprout/darkroom/materials/texture_map.hpp
@@ -90,7 +90,7 @@ namespace sprout {
 					return sprout::darkroom::materials::bilinear_interpolate(
 						get_color(x0, y0), get_color(x0 + 1, y0),
 						get_color(x0, y0 + 1), get_color(x0 + 1, y0 + 1),
-						1 - (x - x0), 1 - (y - y0)
+						x - x0, y - y0
 						);
 				}
 				template<typename Unit>
diff --git a/sprout/darkroom/renderers.hpp b/sprout/darkroom/renderers.hpp
index 9871c828..00e5825e 100644
--- a/sprout/darkroom/renderers.hpp
+++ b/sprout/darkroom/renderers.hpp
@@ -2,6 +2,7 @@
 #define SPROUT_DARKROOM_RENDERERS_HPP
 
 #include <sprout/config.hpp>
+#include <sprout/darkroom/renderers/infinity.hpp>
 #include <sprout/darkroom/renderers/whitted_style.hpp>
 
 #endif	// #ifndef SPROUT_DARKROOM_RENDERERS_HPP
diff --git a/sprout/darkroom/renderers/infinity.hpp b/sprout/darkroom/renderers/infinity.hpp
new file mode 100644
index 00000000..fc6ce33e
--- /dev/null
+++ b/sprout/darkroom/renderers/infinity.hpp
@@ -0,0 +1,80 @@
+#ifndef SPROUT_DARKROOM_RENDERERS_INFINITY_HPP
+#define SPROUT_DARKROOM_RENDERERS_INFINITY_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/tuple/functions.hpp>
+#include <sprout/darkroom/colors/rgb.hpp>
+#include <sprout/darkroom/coords/vector.hpp>
+
+namespace sprout {
+	namespace darkroom {
+		namespace renderers {
+			//
+			// normal_to_color
+			//
+			template<typename Color, typename Normal>
+			inline SPROUT_CONSTEXPR Color normal_to_color(Normal const& nor) {
+				return sprout::tuples::make<Color>(
+					0.5 + sprout::darkroom::coords::x(nor) * 0.5,
+					0.5 + sprout::darkroom::coords::y(nor) * 0.5,
+					0.5 + sprout::darkroom::coords::z(nor) * 0.5
+					);
+			}
+
+			//
+			// direction_gradation
+			//
+			class direction_gradation {
+			public:
+				template<typename TargetColor, typename Vector>
+				SPROUT_CONSTEXPR TargetColor operator()(Vector const& dir) const {
+					return sprout::darkroom::renderers::normal_to_color<TargetColor>(dir);
+				}
+			};
+			//
+			// make_direction_gradation
+			//
+			inline SPROUT_CONSTEXPR sprout::darkroom::renderers::direction_gradation
+			make_direction_gradation() {
+				return sprout::darkroom::renderers::direction_gradation();
+			}
+
+			//
+			// uniform_color
+			//
+			template<typename Color = sprout::darkroom::colors::rgb_f>
+			class uniform_color {
+			public:
+				typedef Color color_type;
+			private:
+				color_type color_;
+			public:
+				SPROUT_CONSTEXPR uniform_color()
+					: color_()
+				{}
+				SPROUT_CONSTEXPR uniform_color(uniform_color const&) = default;
+				explicit SPROUT_CONSTEXPR uniform_color(color_type const& color)
+					: color_(color)
+				{}
+				template<typename TargetColor, typename Vector>
+				SPROUT_CONSTEXPR TargetColor operator()(Vector const&) const {
+					return color_;
+				}
+			};
+			//
+			// make_uniform_color
+			//
+			inline SPROUT_CONSTEXPR sprout::darkroom::renderers::uniform_color<>
+			make_uniform_color() {
+				return sprout::darkroom::renderers::uniform_color<>();
+			}
+			template<typename Color>
+			inline SPROUT_CONSTEXPR sprout::darkroom::renderers::uniform_color<Color>
+			make_uniform_color(Color const& color) {
+				return sprout::darkroom::renderers::uniform_color<Color>(color);
+			}
+		}	// namespace renderers
+	}	// namespace darkroom
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_DARKROOM_RENDERERS_INFINITY_HPP
diff --git a/sprout/darkroom/renderers/whitted_style.hpp b/sprout/darkroom/renderers/whitted_style.hpp
index 0e4991db..407843b4 100644
--- a/sprout/darkroom/renderers/whitted_style.hpp
+++ b/sprout/darkroom/renderers/whitted_style.hpp
@@ -13,6 +13,7 @@
 #include <sprout/darkroom/materials/material.hpp>
 #include <sprout/darkroom/intersects/intersection.hpp>
 #include <sprout/darkroom/objects/intersect.hpp>
+#include <sprout/darkroom/renderers/infinity.hpp>
 
 namespace sprout {
 	namespace darkroom {
@@ -113,7 +114,12 @@ namespace sprout {
 			//
 			// whitted_style
 			//
+			template<typename InfinityColor = sprout::darkroom::renderers::direction_gradation>
 			class whitted_style {
+			public:
+				typedef InfinityColor infinity_color_type;
+			private:
+				infinity_color_type infinity_color_;
 			private:
 				template<
 					typename Color,
@@ -141,7 +147,7 @@ namespace sprout {
 								sprout::darkroom::materials::reflection(sprout::darkroom::intersects::material(inter))
 								)
 							)
-						: sprout::darkroom::coords::normal_to_color<Color>(sprout::darkroom::rays::direction(ray))
+						: infinity_color_.template operator()<Color>(sprout::darkroom::rays::direction(ray))
 						;
 				}
 				template<
@@ -205,6 +211,13 @@ namespace sprout {
 						);
 				}
 			public:
+				SPROUT_CONSTEXPR whitted_style()
+					: infinity_color_()
+				{}
+				SPROUT_CONSTEXPR whitted_style(whitted_style const&) = default;
+				explicit SPROUT_CONSTEXPR whitted_style(infinity_color_type const& infinity_color)
+					: infinity_color_(infinity_color)
+				{}
 				template<
 					typename Color,
 					typename Camera,
@@ -230,6 +243,18 @@ namespace sprout {
 						);
 				}
 			};
+			//
+			// make_whitted_style
+			//
+			inline SPROUT_CONSTEXPR sprout::darkroom::renderers::whitted_style<>
+			make_whitted_style() {
+				return sprout::darkroom::renderers::whitted_style<>();
+			}
+			template<typename InfinityColor>
+			inline SPROUT_CONSTEXPR sprout::darkroom::renderers::whitted_style<InfinityColor>
+			make_whitted_style(InfinityColor const& infinity_color) {
+				return sprout::darkroom::renderers::whitted_style<InfinityColor>(infinity_color);
+			}
 		}	// namespace renderers
 	}	// namespace darkroom
 }	// namespace sprout
diff --git a/sprout/darkroom/tracers/raytracer.hpp b/sprout/darkroom/tracers/raytracer.hpp
index 7b92036d..c41a6cfd 100644
--- a/sprout/darkroom/tracers/raytracer.hpp
+++ b/sprout/darkroom/tracers/raytracer.hpp
@@ -44,6 +44,18 @@ namespace sprout {
 						);
 				}
 			};
+			//
+			// make_raytracer
+			//
+			inline SPROUT_CONSTEXPR sprout::darkroom::tracers::raytracer<>
+			make_raytracer() {
+				return sprout::darkroom::tracers::raytracer<>();
+			}
+			template<typename Color>
+			inline SPROUT_CONSTEXPR sprout::darkroom::tracers::raytracer<Color>
+			make_raytracer() {
+				return sprout::darkroom::tracers::raytracer<Color>();
+			}
 		}	// namespace tracers
 	}	// namespace darkroom
 }	// namespace sprout
diff --git a/sprout/functional/bind/bind.hpp b/sprout/functional/bind/bind.hpp
index 44b9d888..e5e126fc 100644
--- a/sprout/functional/bind/bind.hpp
+++ b/sprout/functional/bind/bind.hpp
@@ -560,12 +560,12 @@ namespace sprout {
 	template<typename F, typename... BoundArgs>
 	inline SPROUT_CONSTEXPR typename sprout::detail::bind_helper<F, BoundArgs...>::type const
 	cbind(F&& f, BoundArgs&&... args) {
-		sprout::bind(sprout::forward<F>(f), sprout::forward<BoundArgs>(args)...);
+		return sprout::bind(sprout::forward<F>(f), sprout::forward<BoundArgs>(args)...);
 	}
 	template<typename R, typename F, typename... BoundArgs>
 	inline SPROUT_CONSTEXPR typename sprout::detail::bindres_helper<R, F, BoundArgs...>::type const
 	cbind(F&& f, BoundArgs&&... args) {
-		sprout::bind<R>(sprout::forward<F>(f), sprout::forward<BoundArgs>(args)...);
+		return sprout::bind<R>(sprout::forward<F>(f), sprout::forward<BoundArgs>(args)...);
 	}
 }	// namespace sprout