X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=gamma_expansion_effect.cpp;h=95437906f4c63134232e7775ba630016b2b6748f;hp=5f9423f7c749081f965d57bbb8ba06901381ca08;hb=95edbfccb0843da3cc105dadc5bc6d8e102f6071;hpb=b912dbaa253ed1f091fd7201efd366c6f3154257

diff --git a/gamma_expansion_effect.cpp b/gamma_expansion_effect.cpp
index 5f9423f..9543790 100644
--- a/gamma_expansion_effect.cpp
+++ b/gamma_expansion_effect.cpp
@@ -1,17 +1,20 @@
-#include <math.h>
 #include <assert.h>
 
 #include "effect_util.h"
 #include "gamma_expansion_effect.h"
 #include "util.h"
 
+using namespace std;
+
+namespace movit {
+
 GammaExpansionEffect::GammaExpansionEffect()
 	: source_curve(GAMMA_LINEAR)
 {
 	register_int("source_curve", (int *)&source_curve);
 }
 
-std::string GammaExpansionEffect::output_fragment_shader()
+string GammaExpansionEffect::output_fragment_shader()
 {
 	if (source_curve == GAMMA_LINEAR) {
 		return read_file("identity.frag");
@@ -24,7 +27,7 @@ std::string GammaExpansionEffect::output_fragment_shader()
 	assert(false);
 }
 
-void GammaExpansionEffect::set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num)
+void GammaExpansionEffect::set_gl_state(GLuint glsl_program_num, const string &prefix, unsigned *sampler_num)
 {
 	Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
 
@@ -37,7 +40,7 @@ void GammaExpansionEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 	// However, pow() is relatively slow in GLSL, so we approximate this
 	// part by a minimax polynomial, whose coefficients are precalculated
 	// in Maple. (It is very hard to accurately model the curve as a whole
-	// using minimax polynomials; both Maple and Mathematically generally
+	// using minimax polynomials; both Maple and Mathematica generally
 	// just error out if you ask them to optimize over 0..1 with a higher-degree
 	// polynomial.)
 	//
@@ -74,6 +77,9 @@ void GammaExpansionEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 		// maxerror      = 0.000094
 		// error at beta = 0.000012
 		// error at 1.0  = 0.000012
+		//
+		// Note that the worst _relative_ error by far is just at the beginning
+		// of the exponential curve, ie., just around β.
 		set_uniform_float(glsl_program_num, prefix, "linear_scale", 1.0 / 12.92);
 		set_uniform_float(glsl_program_num, prefix, "c0", 0.001324469581);
 		set_uniform_float(glsl_program_num, prefix, "c1", 0.02227416690);
@@ -117,3 +123,5 @@ void GammaExpansionEffect::set_gl_state(GLuint glsl_program_num, const std::stri
 		set_uniform_float(glsl_program_num, prefix, "beta", 0.0181 * 4.5);
 	}
 }
+
+}  // namespace movit