Built in gamma conversion for all machines, assuming an output of 2.8 for PAL, 2.2 for NTSC.

OSBindings/Mac/Clock Signal/Machine/CSMachine.mm

@@ -116,6 +116,9 @@ struct MachineDelegate: CRTMachine::Machine::Delegate {
 
 - (void)setupOutputWithAspectRatio:(float)aspectRatio {
 	self.machine->setup_output(aspectRatio);
+
+	// Since OS X v10.6, Macs have had a gamma of 2.2.
+	self.machine->get_crt()->set_output_gamma(2.2f);
 }
 
 - (void)drawViewForPixelSize:(CGSize)pixelSize onlyIfDirty:(BOOL)onlyIfDirty {

Outputs/CRT/CRT.cpp

@@ -56,10 +56,12 @@ void CRT::set_new_display_type(unsigned int cycles_per_line, DisplayType display
 	switch(displayType) {
 		case DisplayType::PAL50:
 			set_new_timing(cycles_per_line, 312, ColourSpace::YUV, 709379, 2500, 5, true);	// i.e. 283.7516; 2.5 lines = vertical sync
+			set_input_gamma(2.8f);
 		break;
 
 		case DisplayType::NTSC60:
 			set_new_timing(cycles_per_line, 262, ColourSpace::YIQ, 455, 2, 6, false);	// i.e. 227.5, 3 lines = vertical sync
+			set_input_gamma(2.2f);
 		break;
 	}
 }
@@ -72,6 +74,21 @@ void CRT::set_composite_function_type(CompositeSourceType type, float offset_of_
 	}
 }
 
+void CRT::set_input_gamma(float gamma) {
+	input_gamma_ = gamma;
+	update_gamma();
+}
+
+void CRT::set_output_gamma(float gamma) {
+	output_gamma_ = gamma;
+	update_gamma();
+}
+
+void CRT::update_gamma() {
+	float gamma_ratio = output_gamma_ / input_gamma_;
+	openGL_output_builder_.set_gamma(gamma_ratio);
+}
+
 CRT::CRT(unsigned int common_output_divisor, unsigned int buffer_depth) :
 	is_receiving_sync_(false),
 	common_output_divisor_(common_output_divisor),

Outputs/CRT/CRT.hpp

@@ -97,6 +97,9 @@ class CRT {
 
 		unsigned int cycles_per_line_;
 
+		float input_gamma_, output_gamma_;
+		void update_gamma();
+
 	public:
 		/*!	Constructs the CRT with a specified clock rate, height and colour subcarrier frequency.
 			The requested number of buffers, each with the requested number of bytes per pixel,
@@ -238,6 +241,12 @@ class CRT {
 			openGL_output_builder_.draw_frame(output_width, output_height, only_if_dirty);
 		}
 
+		/*!	Sets the gamma exponent for the simulated screen. */
+		void set_input_gamma(float gamma);
+
+		/*!	Sets the gamma exponent for the real, tangible screen on which content will be drawn. */
+		void set_output_gamma(float gamma);
+
 		/*!	Tells the CRT that the next call to draw_frame will occur on a different OpenGL context than
 			the previous.
 

Outputs/CRT/Internals/CRTOpenGL.cpp

@@ -89,6 +89,7 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 
 		set_timing_uniforms();
 		set_colour_space_uniforms();
+		set_gamma();
 	}
 
 	if(fence_ != nullptr) {
@@ -375,6 +376,10 @@ void OpenGLOutputBuilder::set_colour_space_uniforms() {
 	if(composite_chrominance_filter_shader_program_)	composite_chrominance_filter_shader_program_->set_colour_conversion_matrices(fromRGB, toRGB);
 }
 
+void OpenGLOutputBuilder::set_gamma() {
+	if(output_shader_program_) output_shader_program_->set_gamma_ratio(gamma_);
+}
+
 float OpenGLOutputBuilder::get_composite_output_width() const {
 	return ((float)colour_cycle_numerator_ * 4.0f) / (float)(colour_cycle_denominator_ * IntermediateBufferWidth);
 }

Outputs/CRT/Internals/CRTOpenGL.hpp

@@ -34,6 +34,7 @@ class OpenGLOutputBuilder {
 		unsigned int colour_cycle_numerator_;
 		unsigned int colour_cycle_denominator_;
 		OutputDevice output_device_;
+		float gamma_;
 
 		// timing information to allow reasoning about input information
 		unsigned int input_frequency_;
@@ -89,6 +90,7 @@ class OpenGLOutputBuilder {
 
 		void set_timing_uniforms();
 		void set_colour_space_uniforms();
+		void set_gamma();
 
 		void establish_OpenGL_state();
 		void reset_all_OpenGL_state();
@@ -118,6 +120,11 @@ class OpenGLOutputBuilder {
 			visible_area_ = visible_area;
 		}
 
+		inline void set_gamma(float gamma) {
+			gamma_ = gamma;
+			set_gamma();
+		}
+
 		inline std::unique_lock<std::mutex> get_output_lock() {
 			return std::unique_lock<std::mutex>(output_mutex_);
 		}

Outputs/CRT/Internals/Shaders/OutputShader.cpp

@@ -74,12 +74,13 @@ std::unique_ptr<OutputShader> OutputShader::make_shader(const char *fragment_met
 		"out vec4 fragColour;"
 
 		"uniform %s texID;"
+		"uniform float gamma;"
 
 		"\n%s\n"
 
 		"void main(void)"
 		"{"
-			"fragColour = vec4(%s, 0.5);"//*cos(lateralVarying)
+			"fragColour = vec4(pow(%s, vec3(gamma)), 0.5);"//*cos(lateralVarying)
 		"}",
 	sampler_type, fragment_methods, colour_expression);
 
@@ -116,6 +117,10 @@ void OutputShader::set_timing(unsigned int height_of_display, unsigned int cycle
 	set_uniform("positionConversion", (GLfloat)horizontal_scan_period, (GLfloat)vertical_scan_period / (GLfloat)vertical_period_divider);
 }
 
+void OutputShader::set_gamma_ratio(float ratio) {
+	set_uniform("gamma", ratio);
+}
+
 void OutputShader::set_input_width_scaler(float input_scaler) {
 	set_uniform("inputScaler", input_scaler);
 }

Outputs/CRT/Internals/Shaders/OutputShader.hpp

@@ -63,6 +63,8 @@ public:
 	*/
 	void set_origin_is_double_height(bool is_double_height);
 
+	void set_gamma_ratio(float ratio);
+
 	/*!
 		Sets the proportion of the input area that should be considered the whole width — 1.0 means use all available
 		space, 0.5 means use half, etc.