X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=gamma_expansion_effect.cpp;h=696815ed40273ea9fb8daab2e2a1d29bff30684b;hb=f8e636666b3d36f97b125bc1a0f0f582c5026c7f;hp=5f9423f7c749081f965d57bbb8ba06901381ca08;hpb=b912dbaa253ed1f091fd7201efd366c6f3154257;p=movit

diff --git a/gamma_expansion_effect.cpp b/gamma_expansion_effect.cpp
index 5f9423f..696815e 100644
--- a/gamma_expansion_effect.cpp
+++ b/gamma_expansion_effect.cpp
@@ -1,17 +1,18 @@
-#include <math.h>
 #include <assert.h>
 
 #include "effect_util.h"
 #include "gamma_expansion_effect.h"
 #include "util.h"
 
+using namespace std;
+
 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 +25,7 @@ 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);
 
@@ -74,6 +75,9 @@ 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);