Brought monitor mode inside the pipeline and added an intermediate filter.

Outputs/CRT/CRT.cpp

@@ -45,7 +45,7 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
 	unsigned int real_clock_scan_period = (_cycles_per_line * height_of_display) / (_time_multiplier * _common_output_divisor);
 	_vertical_flywheel_output_divider = (uint16_t)(ceilf(real_clock_scan_period / 65536.0f) * (_time_multiplier * _common_output_divisor));
 
-	_openGL_output_builder->set_timing(_cycles_per_line, _height_of_display, _horizontal_flywheel->get_scan_period(), _vertical_flywheel->get_scan_period(), _vertical_flywheel_output_divider);
+	_openGL_output_builder->set_timing(cycles_per_line, _cycles_per_line, _height_of_display, _horizontal_flywheel->get_scan_period(), _vertical_flywheel->get_scan_period(), _vertical_flywheel_output_divider);
 }
 
 void CRT::set_new_display_type(unsigned int cycles_per_line, DisplayType displayType)
@@ -133,7 +133,7 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
 		uint8_t *next_run = nullptr;
 		if(is_output_segment)
 		{
-			next_run = (_openGL_output_builder->get_output_device() == Monitor) ? _openGL_output_builder->get_next_output_run() : _openGL_output_builder->get_next_source_run();
+			next_run = _openGL_output_builder->get_next_source_run();
 		}
 
 		//	Vertex output is arranged for triangle strips, as:
@@ -142,20 +142,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
 		//
 		//	[0/1]		3
 		if(next_run)
-		{
-			if(_openGL_output_builder->get_output_device() == Monitor)
-			{
-				// set the type, initial raster position and type of this run
-				output_position_x(0) = output_position_x(1) = output_position_x(2) = (uint16_t)_horizontal_flywheel->get_current_output_position();
-				output_position_y(0) = output_position_y(1) = output_position_y(2) = (uint16_t)(_vertical_flywheel->get_current_output_position() / _vertical_flywheel_output_divider);
-				output_tex_x(0) = output_tex_x(1) = output_tex_x(2) = tex_x;
-
-				// these things are constants across the line so just throw them out now
-				output_tex_y(0) = output_tex_y(1) = output_tex_y(2) = output_tex_y(3) = output_tex_y(4) = output_tex_y(5) = tex_y;
-				output_lateral(0) = output_lateral(1) = output_lateral(3) = 0;
-				output_lateral(2) = output_lateral(4) = output_lateral(5) = 1;
-			}
-			else
 		{
 			source_input_position_x(0) = tex_x;
 			source_input_position_y(0) = source_input_position_y(1) = tex_y;
@@ -167,7 +153,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
 			source_offset(0) = 0;
 			source_offset(1) = 255;
 		}
-		}
 
 		// decrement the number of cycles left to run for and increment the
 		// horizontal counter appropriately
@@ -188,27 +173,13 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
 			// if this is a data run then advance the buffer pointer
 			if(type == Scan::Type::Data && source_divider) tex_x += next_run_length / (_time_multiplier * source_divider);
 
-			if(_openGL_output_builder->get_output_device() == Monitor)
-			{
-				// store the final raster position
-				output_position_x(3) = output_position_x(4) = output_position_x(5) = (uint16_t)_horizontal_flywheel->get_current_output_position();
-				output_position_y(3) = output_position_y(4) = output_position_y(5) = (uint16_t)(_vertical_flywheel->get_current_output_position() / _vertical_flywheel_output_divider);
-				output_tex_x(3) = output_tex_x(4) = output_tex_x(5) = tex_x;
-
-				_openGL_output_builder->complete_output_run(6);
-			}
-			else
-			{
 			source_input_position_x(1) = tex_x;
 			source_output_position_x(1) = (uint16_t)_horizontal_flywheel->get_current_output_position();
 
 			_openGL_output_builder->complete_source_run();
 		}
-		}
 
 		// if this is horizontal retrace then advance the output line counter and bookend an output run
-		if(_openGL_output_builder->get_output_device() == Television)
-		{
 		Flywheel::SyncEvent honoured_event = Flywheel::SyncEvent::None;
 		if(next_run_length == time_until_vertical_sync_event && next_vertical_sync_event != Flywheel::SyncEvent::None) honoured_event = next_vertical_sync_event;
 		if(next_run_length == time_until_horizontal_sync_event && next_horizontal_sync_event != Flywheel::SyncEvent::None) honoured_event = next_horizontal_sync_event;
@@ -236,7 +207,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
 		{
 			_openGL_output_builder->increment_composite_output_y();
 		}
-		}
 
 		// if this is vertical retrace then adcance a field
 		if(next_run_length == time_until_vertical_sync_event && next_vertical_sync_event == Flywheel::SyncEvent::EndRetrace)

Outputs/CRT/Internals/CRTOpenGL.cpp

@@ -167,13 +167,13 @@ OpenGLOutputBuilder::~OpenGLOutputBuilder()
 void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int output_height, bool only_if_dirty)
 {
 	// establish essentials
-	if(!composite_input_shader_program && !rgb_shader_program)
+	if(!output_shader_program)
 	{
-		prepare_composite_input_shader();
+		prepare_composite_input_shaders();
+		prepare_rgb_input_shaders();
 		prepare_source_vertex_array();
 
-		prepare_composite_output_shader();
+		prepare_output_shader();
-		prepare_rgb_output_shader();
 		prepare_output_vertex_array();
 
 		set_timing_uniforms();
@@ -241,10 +241,30 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 		_buffer_builder->last_uploaded_line = _buffer_builder->_next_write_y_position;
 	}
 
-	// for television, update intermediate buffers and then draw; for a monitor, just draw
+	struct RenderStage {
-	if(_output_device == Television || !rgb_shader_program)
+		OpenGL::TextureTarget *const target;
+		OpenGL::Shader *const shader;
+		float clear_colour[3];
+	};
+
+	RenderStage composite_render_stages[] =
 	{
-		// decide how much to draw
+		{compositeTexture.get(),	composite_input_shader_program.get(),				{0.0, 0.0, 0.0}},
+		{filteredYTexture.get(),	composite_y_filter_shader_program.get(),			{0.0, 0.5, 0.5}},
+		{filteredTexture.get(),		composite_chrominance_filter_shader_program.get(),	{0.0, 0.0, 0.0}},
+		{nullptr}
+	};
+
+	RenderStage rgb_render_stages[] =
+	{
+		{compositeTexture.get(),	rgb_input_shader_program.get(),		{0.0, 0.0, 0.0}},
+		{filteredTexture.get(),		rgb_filter_shader_program.get(),	{0.0, 0.0, 0.0}},
+		{nullptr}
+	};
+
+	RenderStage *active_pipeline = (_output_device == Television || !rgb_input_shader_program) ? composite_render_stages : rgb_render_stages;
+
+	// for television, update intermediate buffers and then draw; for a monitor, just draw
 	if(_drawn_source_buffer_data_pointer != _source_buffer_data_pointer)
 	{
 		// determine how many lines are newly reclaimed; they'll need to be cleared
@@ -268,32 +288,17 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 			glFlushMappedBufferRange(GL_ARRAY_BUFFER, drawing_zones[c*2] / SourceVertexSize, drawing_zones[c*2 + 1] / SourceVertexSize);
 		}
 
-			OpenGL::TextureTarget *targets[] = {
+		while(active_pipeline->target)
-				compositeTexture.get(),
-				filteredYTexture.get(),
-				filteredTexture.get()
-			};
-			OpenGL::Shader *shaders[] = {
-				composite_input_shader_program.get(),
-				composite_y_filter_shader_program.get(),
-				composite_chrominance_filter_shader_program.get()
-			};
-			float clear_colours[][3] = {
-				{0.0, 0.0, 0.0},
-				{0.0, 0.5, 0.5},
-				{0.0, 0.0, 0.0}
-			};
-			for(int stage = 0; stage < 3; stage++)
 		{
 			// switch to the initial texture
-				targets[stage]->bind_framebuffer();
+			active_pipeline->target->bind_framebuffer();
-				shaders[stage]->bind();
+			active_pipeline->shader->bind();
 
 			// clear as desired
 			if(number_of_clearing_zones)
 			{
 				glEnable(GL_SCISSOR_TEST);
-					glClearColor(clear_colours[stage][0], clear_colours[stage][1], clear_colours[stage][2], 1.0);
+				glClearColor(active_pipeline->clear_colour[0], active_pipeline->clear_colour[1], active_pipeline->clear_colour[2], 1.0);
 				for(int c = 0; c < number_of_clearing_zones; c++)
 				{
 					glScissor(0, clearing_zones[c*2], IntermediateBufferWidth, clearing_zones[c*2 + 1]);
@@ -307,39 +312,12 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 			{
 				glDrawArrays(GL_LINES, drawing_zones[c*2] / SourceVertexSize, drawing_zones[c*2 + 1] / SourceVertexSize);
 			}
+
+			active_pipeline++;
 		}
 	}
 
-		// transfer to screen
+	// transfer to framebuffer
-		perform_output_stage(output_width, output_height, composite_output_shader_program.get());
-	}
-	else
-		perform_output_stage(output_width, output_height, rgb_shader_program.get());
-
-	// copy framebuffer to the intended place
-	glDisable(GL_BLEND);
-	glBindFramebuffer(GL_FRAMEBUFFER, 0);
-	glViewport(0, 0, (GLsizei)output_width, (GLsizei)output_height);
-	glClear(GL_COLOR_BUFFER_BIT);
-	framebuffer->draw((float)output_width / (float)output_height);
-
-	// drawing commands having been issued, reclaim the array buffer pointer
-	glBindBuffer(GL_ARRAY_BUFFER, output_array_buffer);
-	_output_buffer_data = (uint8_t *)glMapBufferRange(GL_ARRAY_BUFFER, 0, OutputVertexBufferDataSize, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-
-	glBindBuffer(GL_ARRAY_BUFFER, source_array_buffer);
-	_source_buffer_data = (uint8_t *)glMapBufferRange(GL_ARRAY_BUFFER, 0, SourceVertexBufferDataSize, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-
-	_input_texture_data = (uint8_t *)glMapBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, _input_texture_array_size, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-
-	_output_mutex->unlock();
-}
-
-void OpenGLOutputBuilder::perform_output_stage(unsigned int output_width, unsigned int output_height, OpenGL::OutputShader *const shader)
-{
-	if(shader)
-	{
-		// bind the target
 	framebuffer->bind_framebuffer();
 
 	// draw all pending lines
@@ -367,11 +345,11 @@ void OpenGLOutputBuilder::perform_output_stage(unsigned int output_width, unsign
 		// update uniforms (implicitly binding the shader)
 		if(_last_output_width != output_width || _last_output_height != output_height)
 		{
-				shader->set_output_size(output_width, output_height, _visible_area);
+			output_shader_program->set_output_size(output_width, output_height, _visible_area);
 			_last_output_width = output_width;
 			_last_output_height = output_height;
 		}
-			shader->bind();
+		output_shader_program->bind();
 
 		// draw
 		for(int c = 0; c < number_of_drawing_zones; c++)
@@ -379,6 +357,30 @@ void OpenGLOutputBuilder::perform_output_stage(unsigned int output_width, unsign
 			glDrawArrays(GL_TRIANGLE_STRIP, drawing_zones[c*2] / OutputVertexSize, drawing_zones[c*2 + 1] / OutputVertexSize);
 		}
 	}
+
+	// copy framebuffer to the intended place
+	glDisable(GL_BLEND);
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	glViewport(0, 0, (GLsizei)output_width, (GLsizei)output_height);
+	glClear(GL_COLOR_BUFFER_BIT);
+	framebuffer->draw((float)output_width / (float)output_height);
+
+	// drawing commands having been issued, reclaim the array buffer pointer
+	glBindBuffer(GL_ARRAY_BUFFER, output_array_buffer);
+	_output_buffer_data = (uint8_t *)glMapBufferRange(GL_ARRAY_BUFFER, 0, OutputVertexBufferDataSize, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
+
+	glBindBuffer(GL_ARRAY_BUFFER, source_array_buffer);
+	_source_buffer_data = (uint8_t *)glMapBufferRange(GL_ARRAY_BUFFER, 0, SourceVertexBufferDataSize, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
+
+	_input_texture_data = (uint8_t *)glMapBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, _input_texture_array_size, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
+
+	_output_mutex->unlock();
+}
+
+void OpenGLOutputBuilder::perform_output_stage(unsigned int output_width, unsigned int output_height, OpenGL::OutputShader *const shader)
+{
+	if(shader)
+	{
 	}
 }
 
@@ -398,7 +400,7 @@ void OpenGLOutputBuilder::set_rgb_sampling_function(const char *shader)
 
 #pragma mark - Program compilation
 
-void OpenGLOutputBuilder::prepare_composite_input_shader()
+void OpenGLOutputBuilder::prepare_composite_input_shaders()
 {
 	composite_input_shader_program = OpenGL::IntermediateShader::make_source_conversion_shader(_composite_shader, _rgb_shader);
 	composite_input_shader_program->set_source_texture_unit(source_data_texture_unit);
@@ -413,6 +415,20 @@ void OpenGLOutputBuilder::prepare_composite_input_shader()
 	composite_chrominance_filter_shader_program->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
 }
 
+void OpenGLOutputBuilder::prepare_rgb_input_shaders()
+{
+	if(_rgb_shader)
+	{
+		rgb_input_shader_program = OpenGL::IntermediateShader::make_rgb_source_shader(_rgb_shader);
+		rgb_input_shader_program->set_source_texture_unit(source_data_texture_unit);
+		rgb_input_shader_program->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
+
+		rgb_filter_shader_program = OpenGL::IntermediateShader::make_rgb_filter_shader();
+		rgb_filter_shader_program->set_source_texture_unit(composite_texture_unit);
+		rgb_filter_shader_program->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
+	}
+}
+
 void OpenGLOutputBuilder::prepare_source_vertex_array()
 {
 	if(composite_input_shader_program)
@@ -438,35 +454,19 @@ void OpenGLOutputBuilder::prepare_source_vertex_array()
 	}
 }
 
-void OpenGLOutputBuilder::prepare_rgb_output_shader()
+void OpenGLOutputBuilder::prepare_output_shader()
 {
-	const char *rgb_shader = _rgb_shader;
+	output_shader_program = OpenGL::OutputShader::make_shader("", "texture(texID, srcCoordinatesVarying).rgb", false);
-	if(!_rgb_shader)
+	output_shader_program->set_source_texture_unit(filtered_texture_unit);
-	{
-		rgb_shader =
-			"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
-			"{"
-				"return texture(sampler, coordinate).rgb / vec3(255.0);"
-			"}";
-	}
-
-	rgb_shader_program = OpenGL::OutputShader::make_shader(rgb_shader, "rgb_sample(texID, srcCoordinatesVarying, iSrcCoordinatesVarying)", true);
-	rgb_shader_program->set_source_texture_unit(source_data_texture_unit);
-}
-
-void OpenGLOutputBuilder::prepare_composite_output_shader()
-{
-	composite_output_shader_program = OpenGL::OutputShader::make_shader("", "texture(texID, srcCoordinatesVarying).rgb", false);
-	composite_output_shader_program->set_source_texture_unit(filtered_texture_unit);
 }
 
 void OpenGLOutputBuilder::prepare_output_vertex_array()
 {
-	if(rgb_shader_program)
+	if(output_shader_program)
 	{
-		GLint positionAttribute				= rgb_shader_program->get_attrib_location("position");
+		GLint positionAttribute				= output_shader_program->get_attrib_location("position");
-		GLint textureCoordinatesAttribute	= rgb_shader_program->get_attrib_location("srcCoordinates");
+		GLint textureCoordinatesAttribute	= output_shader_program->get_attrib_location("srcCoordinates");
-		GLint lateralAttribute				= rgb_shader_program->get_attrib_location("lateral");
+		GLint lateralAttribute				= output_shader_program->get_attrib_location("lateral");
 
 		glBindVertexArray(output_vertex_array);
 
@@ -495,8 +495,9 @@ void OpenGLOutputBuilder::set_output_device(OutputDevice output_device)
 	}
 }
 
-void OpenGLOutputBuilder::set_timing(unsigned int cycles_per_line, unsigned int height_of_display, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider)
+void OpenGLOutputBuilder::set_timing(unsigned int input_frequency, unsigned int cycles_per_line, unsigned int height_of_display, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider)
 {
+	_input_frequency = input_frequency;
 	_cycles_per_line = cycles_per_line;
 	_height_of_display = height_of_display;
 	_horizontal_scan_period = horizontal_scan_period;
@@ -540,6 +541,7 @@ void OpenGLOutputBuilder::set_colour_space_uniforms()
 void OpenGLOutputBuilder::set_timing_uniforms()
 {
 	_output_mutex->lock();
+
 	OpenGL::IntermediateShader *intermediate_shaders[] = {
 		composite_input_shader_program.get(),
 		composite_y_filter_shader_program.get(),
@@ -553,17 +555,12 @@ void OpenGLOutputBuilder::set_timing_uniforms()
 		extends = true;
 	}
 
-	OpenGL::OutputShader *output_shaders[] = {
+	if(output_shader_program) output_shader_program->set_timing(_height_of_display, _cycles_per_line, _horizontal_scan_period, _vertical_scan_period, _vertical_period_divider);
-		rgb_shader_program.get(),
-		composite_output_shader_program.get()
-	};
-	for(int c = 0; c < 2; c++)
-	{
-		if(output_shaders[c]) output_shaders[c]->set_timing(_height_of_display, _cycles_per_line, _horizontal_scan_period, _vertical_scan_period, _vertical_period_divider);
-	}
 
 	float colour_subcarrier_frequency = (float)_colour_cycle_numerator / (float)_colour_cycle_denominator;
-	if(composite_y_filter_shader_program) composite_y_filter_shader_program->set_filter_coefficients(_cycles_per_line, colour_subcarrier_frequency - 90.0f);
+	if(composite_y_filter_shader_program)			composite_y_filter_shader_program->set_separation_frequency(_cycles_per_line, colour_subcarrier_frequency);
 	if(composite_chrominance_filter_shader_program)	composite_chrominance_filter_shader_program->set_filter_coefficients(_cycles_per_line, colour_subcarrier_frequency * 0.5f);
+	if(rgb_filter_shader_program)					rgb_filter_shader_program->set_filter_coefficients(_cycles_per_line, (float)_input_frequency * 0.5f);
+
 	_output_mutex->unlock();
 }

Outputs/CRT/Internals/CRTOpenGL.hpp

@@ -33,6 +33,7 @@ class OpenGLOutputBuilder {
 		OutputDevice _output_device;
 
 		// timing information to allow reasoning about input information
+		unsigned int _input_frequency;
 		unsigned int _cycles_per_line;
 		unsigned int _height_of_display;
 		unsigned int _horizontal_scan_period;
@@ -47,9 +48,9 @@ class OpenGLOutputBuilder {
 		char *_rgb_shader;
 
 		// Methods used by the OpenGL code
-		void prepare_rgb_output_shader();
+		void prepare_output_shader();
-		void prepare_composite_output_shader();
+		void prepare_rgb_input_shaders();
-		void prepare_composite_input_shader();
+		void prepare_composite_input_shaders();
 
 		void prepare_output_vertex_array();
 		void prepare_source_vertex_array();
@@ -61,8 +62,9 @@ class OpenGLOutputBuilder {
 		// transient buffers indicating composite data not yet decoded
 		uint16_t _composite_src_output_y, _cleared_composite_output_y;
 
-		std::unique_ptr<OpenGL::OutputShader> rgb_shader_program, composite_output_shader_program;
+		std::unique_ptr<OpenGL::OutputShader> output_shader_program;
 		std::unique_ptr<OpenGL::IntermediateShader> composite_input_shader_program, composite_y_filter_shader_program, composite_chrominance_filter_shader_program;
+		std::unique_ptr<OpenGL::IntermediateShader> rgb_input_shader_program, rgb_filter_shader_program;
 
 		GLuint output_array_buffer, output_vertex_array;
 		GLuint source_array_buffer, source_vertex_array;
@@ -168,7 +170,7 @@ class OpenGLOutputBuilder {
 		void set_composite_sampling_function(const char *shader);
 		void set_rgb_sampling_function(const char *shader);
 		void set_output_device(OutputDevice output_device);
-		void set_timing(unsigned int cycles_per_line, unsigned int height_of_display, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider);
+		void set_timing(unsigned int input_frequency, unsigned int cycles_per_line, unsigned int height_of_display, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider);
 
 		uint8_t *_input_texture_data;
 		GLuint _input_texture_array;

Outputs/CRT/Internals/Shaders/IntermediateShader.cpp

@@ -141,6 +141,34 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_source_conversion_s
 	return shader;
 }
 
+std::unique_ptr<IntermediateShader> IntermediateShader::make_rgb_source_shader(const char *rgb_shader)
+{
+	char *fragment_shader;
+	asprintf(&fragment_shader,
+		"#version 150\n"
+
+		"in vec2 inputPositionsVarying[11];"
+		"in vec2 iInputPositionVarying;"
+		"in vec2 phaseAndAmplitudeVarying;"
+
+		"out vec3 fragColour;"
+
+		"uniform usampler2D texID;"
+
+		"\n%s\n"
+
+		"void main(void)"
+		"{"
+			"fragColour = rgb_sample(texID, inputPositionsVarying[5], iInputPositionVarying);"
+		"}"
+	, rgb_shader);
+
+	std::unique_ptr<IntermediateShader> shader = make_shader(fragment_shader, true, true);
+	free(fragment_shader);
+
+	return shader;
+}
+
 std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_luma_separation_shader()
 {
 	return make_shader(
@@ -250,6 +278,70 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_filter_shade
 		"}", false, false);
 }
 
+std::unique_ptr<IntermediateShader> IntermediateShader::make_rgb_filter_shader()
+{
+	return make_shader(
+		"#version 150\n"
+
+		"in vec2 inputPositionsVarying[11];"
+		"uniform vec4 weights[3];"
+
+		"out vec3 fragColour;"
+
+		"uniform sampler2D texID;"
+
+		"void main(void)"
+		"{"
+			"vec3 samples[] = vec3[]("
+				"texture(texID, inputPositionsVarying[0]).rgb,"
+				"texture(texID, inputPositionsVarying[1]).rgb,"
+				"texture(texID, inputPositionsVarying[2]).rgb,"
+				"texture(texID, inputPositionsVarying[3]).rgb,"
+				"texture(texID, inputPositionsVarying[4]).rgb,"
+				"texture(texID, inputPositionsVarying[5]).rgb,"
+				"texture(texID, inputPositionsVarying[6]).rgb,"
+				"texture(texID, inputPositionsVarying[7]).rgb,"
+				"texture(texID, inputPositionsVarying[8]).rgb,"
+				"texture(texID, inputPositionsVarying[9]).rgb,"
+				"texture(texID, inputPositionsVarying[10]).rgb"
+			");"
+
+			"vec4 channel1[] = vec4[]("
+				"vec4(samples[0].r, samples[1].r, samples[2].r, samples[3].r),"
+				"vec4(samples[4].r, samples[5].r, samples[6].r, samples[7].r),"
+				"vec4(samples[8].r, samples[9].r, samples[10].r, 0.0)"
+			");"
+			"vec4 channel2[] = vec4[]("
+				"vec4(samples[0].g, samples[1].g, samples[2].g, samples[3].g),"
+				"vec4(samples[4].g, samples[5].g, samples[6].g, samples[7].g),"
+				"vec4(samples[8].g, samples[9].g, samples[10].g, 0.0)"
+			");"
+			"vec4 channel3[] = vec4[]("
+				"vec4(samples[0].b, samples[1].b, samples[2].b, samples[3].b),"
+				"vec4(samples[4].b, samples[5].b, samples[6].b, samples[7].b),"
+				"vec4(samples[8].b, samples[9].b, samples[10].b, 0.0)"
+			");"
+
+			"fragColour = vec3("
+				"dot(vec3("
+					"dot(channel1[0], weights[0]),"
+					"dot(channel1[1], weights[1]),"
+					"dot(channel1[2], weights[2])"
+				"), vec3(1.0)),"
+				"dot(vec3("
+					"dot(channel2[0], weights[0]),"
+					"dot(channel2[1], weights[1]),"
+					"dot(channel2[2], weights[2])"
+				"), vec3(1.0)),"
+				"dot(vec3("
+					"dot(channel3[0], weights[0]),"
+					"dot(channel3[1], weights[1]),"
+					"dot(channel3[2], weights[2])"
+				"), vec3(1.0))"
+			");"
+		"}", false, false);
+}
+
 void IntermediateShader::set_output_size(unsigned int output_width, unsigned int output_height)
 {
 	bind();
@@ -319,6 +411,12 @@ void IntermediateShader::set_filter_coefficients(float sampling_rate, float cuto
 	glUniform1fv(offsetsUniform, 5, offsets);
 }
 
+void IntermediateShader::set_separation_frequency(float sampling_rate, float colour_burst_frequency)
+{
+	// TODO: apply separately-formed filters for luminance and chrominance
+	set_filter_coefficients(sampling_rate, colour_burst_frequency - 50.0f);
+}
+
 void IntermediateShader::set_phase_cycles_per_sample(float phase_cycles_per_sample, bool extend_runs_to_full_cycle)
 {
 	bind();

Outputs/CRT/Internals/Shaders/IntermediateShader.hpp

@@ -27,6 +27,12 @@ public:
 	*/
 	static std::unique_ptr<IntermediateShader> make_source_conversion_shader(const char *composite_shader, const char *rgb_shader);
 
+	/*!
+		Constructs and returns an intermediate shader that will take runs from the inputPositions,
+		converting them to RGB values using @c rgb_shader.
+	*/
+	static std::unique_ptr<IntermediateShader> make_rgb_source_shader(const char *rgb_shader);
+
 	/*!
 		Constructs and returns an intermediate shader that will read composite samples from the R channel,
 		filter then to obtain luminance, stored to R, and to separate out unfiltered chrominance, store to G and B.
@@ -38,6 +44,11 @@ public:
 	*/
 	static std::unique_ptr<IntermediateShader> make_chroma_filter_shader();
 
+	/*!
+		Constructs and returns an intermediate shader that will filter R, G and B.
+	*/
+	static std::unique_ptr<IntermediateShader> make_rgb_filter_shader();
+
 	/*!
 		Binds this shader and configures it for output to an area of `output_width` and `output_height` pixels.
 	*/
@@ -53,6 +64,12 @@ public:
 	*/
 	void set_filter_coefficients(float sampling_rate, float cutoff_frequency);
 
+	/*!
+		Binds this shader and configures filtering to separate luminance and chrominance based on a colour
+		subcarrier of the given frequency.
+	*/
+	void set_separation_frequency(float sampling_rate, float colour_burst_frequency);
+
 	/*!
 		Binds this shader and sets the number of colour phase cycles per sample, indicating whether output
 		geometry should be extended so that a complete colour cycle is included at both the beginning and end.