Merge pull request #97 from TomHarte/Icons

Introduces some file association icons

Components/AY38910/AY38910.cpp

@@ -84,7 +84,7 @@ void AY38910::set_clock_rate(double clock_rate)
 void AY38910::get_samples(unsigned int number_of_samples, int16_t *target)
 {
 	int c = 0;
-	while((master_divider_&15) && c < number_of_samples)
+	while((master_divider_&7) && c < number_of_samples)
 	{
 		target[c] = output_volume_;
 		master_divider_++;
@@ -131,7 +131,7 @@ void AY38910::get_samples(unsigned int number_of_samples, int16_t *target)
 
 		evaluate_output_volume();
 
-		for(int ic = 0; ic < 16 && c < number_of_samples; ic++)
+		for(int ic = 0; ic < 8 && c < number_of_samples; ic++)
 		{
 			target[c] = output_volume_;
 			c++;
@@ -139,7 +139,7 @@ void AY38910::get_samples(unsigned int number_of_samples, int16_t *target)
 		}
 	}
 
-	master_divider_ &= 15;
+	master_divider_ &= 7;
 }
 
 void AY38910::evaluate_output_volume()

Machines/Atari2600/Atari2600.cpp

@@ -71,7 +71,7 @@ void Machine::setup_output(float aspect_ratio)
 			"uint y = c & 14u;"
 			"uint iPhase = (c >> 4);"
 
-			"float phaseOffset = 6.283185308 * float(iPhase - 1u) / 13.0;"
+			"float phaseOffset = 6.283185308 * float(iPhase) / 13.0  + 5.074880441076923;"
 			"return mix(float(y) / 14.0, step(1, iPhase) * cos(phase + phaseOffset), amplitude);"
 		"}");
 	speaker_->set_input_rate((float)(get_clock_rate() / 38.0));
@@ -777,5 +777,6 @@ void Machine::update_audio()
 void Machine::synchronise()
 {
 	update_audio();
+	speaker_->flush();
 }
 

Machines/Electron/Electron.cpp

@@ -61,6 +61,7 @@ std::shared_ptr<Outputs::Speaker> Machine::get_speaker()
 void Machine::clear_all_keys()
 {
 	memset(key_states_, 0, sizeof(key_states_));
+	if(is_holding_shift_) set_key_state(KeyShift, true);
 }
 
 void Machine::set_key_state(uint16_t key, bool isPressed)
@@ -116,10 +117,9 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target)
 		set_typer_for_string(target.loadingCommand.c_str());
 	}
 
-	if(target.acorn.should_hold_shift)
+	if(target.acorn.should_shift_restart)
 	{
-		set_key_state(KeyShift, true);
-		is_holding_shift_ = true;
+		shift_restart_counter_ = 1000000;
 	}
 }
 
@@ -398,6 +398,17 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
 
 	if(typer_) typer_->update((int)cycles);
 	if(plus3_) plus3_->run_for_cycles(4*cycles);
+	if(shift_restart_counter_)
+	{
+		shift_restart_counter_ -= cycles;
+		if(shift_restart_counter_ <= 0)
+		{
+			shift_restart_counter_ = 0;
+			set_power_on(true);
+			set_key_state(KeyShift, true);
+			is_holding_shift_ = true;
+		}
+	}
 
 	return cycles;
 }

Machines/Electron/Electron.hpp

@@ -144,6 +144,7 @@ class Machine:
 		// Disk
 		std::unique_ptr<Plus3> plus3_;
 		bool is_holding_shift_;
+		int shift_restart_counter_;
 
 		// Outputs
 		std::unique_ptr<VideoOutput> video_output_;

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -20,6 +20,7 @@
 		4B1D08061E0F7A1100763741 /* TimeTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B1D08051E0F7A1100763741 /* TimeTests.mm */; };
 		4B1E85751D170228001EF87D /* Typer.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B1E85731D170228001EF87D /* Typer.cpp */; };
 		4B1E85811D176468001EF87D /* 6532Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B1E85801D176468001EF87D /* 6532Tests.swift */; };
+		4B1EDB451E39A0AC009D6819 /* chip.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B1EDB431E39A0AC009D6819 /* chip.png */; };
 		4B2409551C45AB05004DA684 /* Speaker.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2409531C45AB05004DA684 /* Speaker.cpp */; };
 		4B2A332A1DB8544D002876E3 /* MemoryFuzzer.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2A33281DB8544D002876E3 /* MemoryFuzzer.cpp */; };
 		4B2A332D1DB86821002876E3 /* OricOptions.xib in Resources */ = {isa = PBXBuildFile; fileRef = 4B2A332B1DB86821002876E3 /* OricOptions.xib */; };
@@ -31,6 +32,7 @@
 		4B2A53A31D117D36003C6002 /* CSVic20.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B2A539E1D117D36003C6002 /* CSVic20.mm */; };
 		4B2BFC5F1D613E0200BA3AA9 /* TapePRG.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2BFC5D1D613E0200BA3AA9 /* TapePRG.cpp */; };
 		4B2BFDB21DAEF5FF001A68B8 /* Video.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2BFDB01DAEF5FF001A68B8 /* Video.cpp */; };
+		4B2C45421E3C3896002A2389 /* cartridge.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B2C45411E3C3896002A2389 /* cartridge.png */; };
 		4B2E2D9A1C3A06EC00138695 /* Atari2600.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2E2D971C3A06EC00138695 /* Atari2600.cpp */; };
 		4B2E2D9D1C3A070400138695 /* Electron.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B2E2D9B1C3A070400138695 /* Electron.cpp */; };
 		4B30512D1D989E2200B4FED8 /* Drive.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B30512B1D989E2200B4FED8 /* Drive.cpp */; };
@@ -67,6 +69,9 @@
 		4B69FB461C4D950F00B5F0AA /* libz.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B69FB451C4D950F00B5F0AA /* libz.tbd */; };
 		4B6C73BD1D387AE500AFCFCA /* DiskController.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B6C73BB1D387AE500AFCFCA /* DiskController.cpp */; };
 		4B7913CC1DFCD80E00175A82 /* Video.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B7913CA1DFCD80E00175A82 /* Video.cpp */; };
+		4B79E4441E3AF38600141F11 /* cassette.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B79E4411E3AF38600141F11 /* cassette.png */; };
+		4B79E4451E3AF38600141F11 /* floppy35.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B79E4421E3AF38600141F11 /* floppy35.png */; };
+		4B79E4461E3AF38600141F11 /* floppy525.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B79E4431E3AF38600141F11 /* floppy525.png */; };
 		4B8805F01DCFC99C003085B1 /* Acorn.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8805EE1DCFC99C003085B1 /* Acorn.cpp */; };
 		4B8805F41DCFD22A003085B1 /* Commodore.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8805F21DCFD22A003085B1 /* Commodore.cpp */; };
 		4B8805F71DCFF6C9003085B1 /* Commodore.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8805F51DCFF6C9003085B1 /* Commodore.cpp */; };
@@ -447,6 +452,7 @@
 		4B1E85741D170228001EF87D /* Typer.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Typer.hpp; sourceTree = "<group>"; };
 		4B1E857B1D174DEC001EF87D /* 6532.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = 6532.hpp; sourceTree = "<group>"; };
 		4B1E85801D176468001EF87D /* 6532Tests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = 6532Tests.swift; sourceTree = "<group>"; };
+		4B1EDB431E39A0AC009D6819 /* chip.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = chip.png; sourceTree = "<group>"; };
 		4B2409531C45AB05004DA684 /* Speaker.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Speaker.cpp; path = ../../Outputs/Speaker.cpp; sourceTree = "<group>"; };
 		4B2409541C45AB05004DA684 /* Speaker.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = Speaker.hpp; path = ../../Outputs/Speaker.hpp; sourceTree = "<group>"; };
 		4B24095A1C45DF85004DA684 /* Stepper.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Stepper.hpp; sourceTree = "<group>"; };
@@ -471,6 +477,7 @@
 		4B2BFC5E1D613E0200BA3AA9 /* TapePRG.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = TapePRG.hpp; sourceTree = "<group>"; };
 		4B2BFDB01DAEF5FF001A68B8 /* Video.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Video.cpp; path = Oric/Video.cpp; sourceTree = "<group>"; };
 		4B2BFDB11DAEF5FF001A68B8 /* Video.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = Video.hpp; path = Oric/Video.hpp; sourceTree = "<group>"; };
+		4B2C45411E3C3896002A2389 /* cartridge.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = cartridge.png; sourceTree = "<group>"; };
 		4B2E2D971C3A06EC00138695 /* Atari2600.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Atari2600.cpp; sourceTree = "<group>"; };
 		4B2E2D981C3A06EC00138695 /* Atari2600.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Atari2600.hpp; sourceTree = "<group>"; };
 		4B2E2D991C3A06EC00138695 /* Atari2600Inputs.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Atari2600Inputs.h; sourceTree = "<group>"; };
@@ -538,6 +545,9 @@
 		4B6C73BC1D387AE500AFCFCA /* DiskController.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = DiskController.hpp; sourceTree = "<group>"; };
 		4B7913CA1DFCD80E00175A82 /* Video.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Video.cpp; path = Electron/Video.cpp; sourceTree = "<group>"; };
 		4B7913CB1DFCD80E00175A82 /* Video.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = Video.hpp; path = Electron/Video.hpp; sourceTree = "<group>"; };
+		4B79E4411E3AF38600141F11 /* cassette.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = cassette.png; sourceTree = "<group>"; };
+		4B79E4421E3AF38600141F11 /* floppy35.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = floppy35.png; sourceTree = "<group>"; };
+		4B79E4431E3AF38600141F11 /* floppy525.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = floppy525.png; sourceTree = "<group>"; };
 		4B8805EE1DCFC99C003085B1 /* Acorn.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Acorn.cpp; path = Parsers/Acorn.cpp; sourceTree = "<group>"; };
 		4B8805EF1DCFC99C003085B1 /* Acorn.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = Acorn.hpp; path = Parsers/Acorn.hpp; sourceTree = "<group>"; };
 		4B8805F21DCFD22A003085B1 /* Commodore.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Commodore.cpp; path = Parsers/Commodore.cpp; sourceTree = "<group>"; };
@@ -1011,6 +1021,18 @@
 			path = 6532;
 			sourceTree = "<group>";
 		};
+		4B1EDB411E39A0AC009D6819 /* Icons */ = {
+			isa = PBXGroup;
+			children = (
+				4B2C45411E3C3896002A2389 /* cartridge.png */,
+				4B79E4411E3AF38600141F11 /* cassette.png */,
+				4B79E4421E3AF38600141F11 /* floppy35.png */,
+				4B79E4431E3AF38600141F11 /* floppy525.png */,
+				4B1EDB431E39A0AC009D6819 /* chip.png */,
+			);
+			path = Icons;
+			sourceTree = "<group>";
+		};
 		4B2409591C45DF85004DA684 /* SignalProcessing */ = {
 			isa = PBXGroup;
 			children = (
@@ -1899,6 +1921,7 @@
 		4BE5F85A1C3E1C2500C43F01 /* Resources */ = {
 			isa = PBXGroup;
 			children = (
+				4B1EDB411E39A0AC009D6819 /* Icons */,
 				4BC9DF441D044FCA00F44158 /* ROMImages */,
 			);
 			path = Resources;
@@ -2052,13 +2075,18 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				4B2C45421E3C3896002A2389 /* cartridge.png in Resources */,
 				4BB73EA91B587A5100552FC2 /* Assets.xcassets in Resources */,
+				4B79E4451E3AF38600141F11 /* floppy35.png in Resources */,
+				4B1EDB451E39A0AC009D6819 /* chip.png in Resources */,
 				4B2A332D1DB86821002876E3 /* OricOptions.xib in Resources */,
 				4B8FE21B1DA19D5F0090D3CE /* Atari2600Options.xib in Resources */,
 				4B8FE21C1DA19D5F0090D3CE /* MachineDocument.xib in Resources */,
+				4B79E4441E3AF38600141F11 /* cassette.png in Resources */,
 				4B8FE21E1DA19D5F0090D3CE /* Vic20Options.xib in Resources */,
 				4BB73EAC1B587A5100552FC2 /* MainMenu.xib in Resources */,
 				4B8FE21D1DA19D5F0090D3CE /* ElectronOptions.xib in Resources */,
+				4B79E4461E3AF38600141F11 /* floppy525.png in Resources */,
 				4BC9DF451D044FCA00F44158 /* ROMImages in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

OSBindings/Mac/Clock Signal/Info.plist

@@ -13,7 +13,7 @@
 				<string>bin</string>
 			</array>
 			<key>CFBundleTypeIconFile</key>
-			<string></string>
+			<string>cartridge</string>
 			<key>CFBundleTypeName</key>
 			<string>Atari 2600 Cartridge</string>
 			<key>CFBundleTypeOSTypes</key>
@@ -27,27 +27,13 @@
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
 		</dict>
-		<dict>
-			<key>CFBundleTypeExtensions</key>
-			<array>
-				<string>uef</string>
-			</array>
-			<key>CFBundleTypeName</key>
-			<string>Electron/BBC Tape Image</string>
-			<key>CFBundleTypeRole</key>
-			<string>Viewer</string>
-			<key>LSItemContentTypes</key>
-			<array/>
-			<key>LSTypeIsPackage</key>
-			<integer>0</integer>
-			<key>NSDocumentClass</key>
-			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>rom</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>chip</string>
 			<key>CFBundleTypeName</key>
 			<string>ROM Image</string>
 			<key>CFBundleTypeRole</key>
@@ -65,6 +51,8 @@
 				<string>uef</string>
 				<string>uef.gz</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>cassette</string>
 			<key>CFBundleTypeName</key>
 			<string>Electron/BBC UEF Image</string>
 			<key>CFBundleTypeRole</key>
@@ -79,6 +67,8 @@
 			<array>
 				<string>prg</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy525</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore Program</string>
 			<key>CFBundleTypeRole</key>
@@ -93,6 +83,8 @@
 			<array>
 				<string>tap</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>cassette</string>
 			<key>CFBundleTypeName</key>
 			<string>Tape Image</string>
 			<key>CFBundleTypeRole</key>
@@ -107,6 +99,8 @@
 			<array>
 				<string>g64</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy525</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore Disk</string>
 			<key>CFBundleTypeRole</key>
@@ -121,6 +115,8 @@
 			<array>
 				<string>d64</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy525</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore 1540/1 Disk</string>
 			<key>CFBundleTypeRole</key>
@@ -139,6 +135,8 @@
 				<string>adl</string>
 				<string>adm</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy35</string>
 			<key>CFBundleTypeName</key>
 			<string>Electron/BBC Disk Image</string>
 			<key>CFBundleTypeRole</key>
@@ -151,6 +149,8 @@
 			<array>
 				<string>dsk</string>
 			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy35</string>
 			<key>CFBundleTypeName</key>
 			<string>Disk Image</string>
 			<key>CFBundleTypeRole</key>

Outputs/CRT/CRT.cpp

@@ -29,9 +29,9 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
 																//	for horizontal retrace and 500 to 750 µs for vertical retrace in NTSC and PAL TV."
 
 	time_multiplier_ = IntermediateBufferWidth / cycles_per_line;
-	phase_denominator_ = cycles_per_line * colour_cycle_denominator;
+	phase_denominator_ = cycles_per_line * colour_cycle_denominator * time_multiplier_;
 	phase_numerator_ = 0;
-	colour_cycle_numerator_ = colour_cycle_numerator * time_multiplier_;
+	colour_cycle_numerator_ = colour_cycle_numerator;
 	phase_alternates_ = should_alternate;
 	is_alernate_line_ &= phase_alternates_;
 	unsigned int multiplied_cycles_per_line = cycles_per_line * time_multiplier_;
@@ -112,7 +112,6 @@ Flywheel::SyncEvent CRT::get_next_horizontal_sync_event(bool hsync_is_requested,
 #define source_output_position_x2()	(*(uint16_t *)&next_run[SourceVertexOffsetOfEnds + 2])
 #define source_phase()				next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 0]
 #define source_amplitude()			next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 2]
-#define source_phase_time()			next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 1]
 
 void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bool vsync_requested, const bool vsync_charging, const Scan::Type type)
 {
@@ -149,7 +148,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bo
 			source_output_position_x1() = (uint16_t)horizontal_flywheel_->get_current_output_position();
 			source_phase() = colour_burst_phase_;
 			source_amplitude() = colour_burst_amplitude_;
-			source_phase_time() = (uint8_t)colour_burst_time_; // assumption: burst was within the first 1/16 of the line
 		}
 
 		// decrement the number of cycles left to run for and increment the
@@ -242,7 +240,9 @@ void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bo
 				frames_since_last_delegate_call_++;
 				if(frames_since_last_delegate_call_ == 20)
 				{
+					output_lock.unlock();
 					delegate_->crt_did_end_batch_of_frames(this, frames_since_last_delegate_call_, vertical_flywheel_->get_and_reset_number_of_surprises());
+					output_lock.lock();
 					frames_since_last_delegate_call_ = 0;
 				}
 			}
@@ -286,9 +286,11 @@ void CRT::output_scan(const Scan *const scan)
 	{
 		if(horizontal_flywheel_->get_current_time() < (horizontal_flywheel_->get_standard_period() * 12) >> 6)
 		{
-			colour_burst_time_ = (uint16_t)horizontal_flywheel_->get_current_time();
-			colour_burst_phase_ = scan->phase;
+			unsigned int position_phase = (horizontal_flywheel_->get_current_time() * colour_cycle_numerator_ * 256) / phase_denominator_;
+			colour_burst_phase_ = (position_phase + scan->phase) & 255;
 			colour_burst_amplitude_ = scan->amplitude;
+
+			colour_burst_phase_ = (colour_burst_phase_ & ~63) + 32;
 		}
 	}
 
@@ -344,7 +346,7 @@ void CRT::output_default_colour_burst(unsigned int number_of_cycles)
 	Scan scan {
 		.type = Scan::Type::ColourBurst,
 		.number_of_cycles = number_of_cycles,
-		.phase = (uint8_t)((phase_numerator_ * 255) / phase_denominator_ + (is_alernate_line_ ? 128 : 0)),
+		.phase = (uint8_t)((phase_numerator_ * 256) / phase_denominator_ + (is_alernate_line_ ? 128 : 0)),
 		.amplitude = 32
 	};
 	output_scan(&scan);

Outputs/CRT/CRT.hpp

@@ -60,7 +60,6 @@ class CRT {
 		void output_scan(const Scan *scan);
 
 		uint8_t colour_burst_phase_, colour_burst_amplitude_;
-		uint16_t colour_burst_time_;
 		bool is_writing_composite_run_;
 
 		unsigned int phase_denominator_, phase_numerator_, colour_cycle_numerator_;

Outputs/CRT/Internals/CRTConstants.hpp

@@ -36,7 +36,7 @@ const GLsizei InputBufferBuilderWidth = 2048;
 const GLsizei InputBufferBuilderHeight = 512;
 
 // This is the size of the intermediate buffers used during composite to RGB conversion
-const GLsizei IntermediateBufferWidth = 4096;
+const GLsizei IntermediateBufferWidth = 2048;
 const GLsizei IntermediateBufferHeight = 512;
 
 // Some internal buffer sizes

Outputs/CRT/Internals/CRTOpenGL.cpp

@@ -6,8 +6,10 @@
 //
 
 #include "CRT.hpp"
-#include <stdlib.h>
-#include <math.h>
+
+#include <cstdlib>
+#include <cstring>
+#include <cmath>
 
 #include "CRTOpenGL.hpp"
 #include "../../../SignalProcessing/FIRFilter.hpp"
@@ -16,12 +18,14 @@
 using namespace Outputs::CRT;
 
 namespace {
-	static const GLenum composite_texture_unit			= GL_TEXTURE0;
-	static const GLenum separated_texture_unit			= GL_TEXTURE1;
-	static const GLenum filtered_y_texture_unit			= GL_TEXTURE2;
-	static const GLenum filtered_texture_unit			= GL_TEXTURE3;
-	static const GLenum source_data_texture_unit		= GL_TEXTURE4;
-	static const GLenum pixel_accumulation_texture_unit	= GL_TEXTURE5;
+	static const GLenum source_data_texture_unit		= GL_TEXTURE0;
+	static const GLenum pixel_accumulation_texture_unit	= GL_TEXTURE1;
+
+	static const GLenum composite_texture_unit			= GL_TEXTURE2;
+	static const GLenum separated_texture_unit			= GL_TEXTURE3;
+	static const GLenum filtered_texture_unit			= GL_TEXTURE4;
+
+	static const GLenum work_texture_unit				= GL_TEXTURE2;
 }
 
 OpenGLOutputBuilder::OpenGLOutputBuilder(size_t bytes_per_pixel) :
@@ -33,11 +37,7 @@ OpenGLOutputBuilder::OpenGLOutputBuilder(size_t bytes_per_pixel) :
 	last_output_height_(0),
 	fence_(nullptr),
 	texture_builder(bytes_per_pixel, source_data_texture_unit),
-	array_builder(SourceVertexBufferDataSize, OutputVertexBufferDataSize),
-	composite_texture_(IntermediateBufferWidth, IntermediateBufferHeight, composite_texture_unit),
-	separated_texture_(IntermediateBufferWidth, IntermediateBufferHeight, separated_texture_unit),
-	filtered_y_texture_(IntermediateBufferWidth, IntermediateBufferHeight, filtered_y_texture_unit),
-	filtered_texture_(IntermediateBufferWidth, IntermediateBufferHeight, filtered_texture_unit)
+	array_builder(SourceVertexBufferDataSize, OutputVertexBufferDataSize)
 {
 	glBlendFunc(GL_SRC_ALPHA, GL_CONSTANT_COLOR);
 	glBlendColor(0.6f, 0.6f, 0.6f, 1.0f);
@@ -47,6 +47,32 @@ OpenGLOutputBuilder::OpenGLOutputBuilder(size_t bytes_per_pixel) :
 
 	// create the source vertex array
 	glGenVertexArrays(1, &source_vertex_array_);
+
+	bool supports_texture_barrier = false;
+#ifdef GL_NV_texture_barrier
+	GLint number_of_extensions;
+	glGetIntegerv(GL_NUM_EXTENSIONS, &number_of_extensions);
+
+	for(GLuint c = 0; c < (GLuint)number_of_extensions; c++)
+	{
+		const char *extension_name = (const char *)glGetStringi(GL_EXTENSIONS, c);
+		if(!strcmp(extension_name, "GL_NV_texture_barrier"))
+		{
+			supports_texture_barrier = true;
+		}
+	}
+#endif
+
+//	if(supports_texture_barrier)
+//	{
+//		work_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight*2, work_texture_unit));
+//	}
+//	else
+	{
+		composite_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, composite_texture_unit, GL_NEAREST));
+		separated_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, separated_texture_unit, GL_NEAREST));
+		filtered_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, filtered_texture_unit, GL_LINEAR));
+	}
 }
 
 OpenGLOutputBuilder::~OpenGLOutputBuilder()
@@ -57,6 +83,11 @@ OpenGLOutputBuilder::~OpenGLOutputBuilder()
 	free(rgb_shader_);
 }
 
+bool OpenGLOutputBuilder::get_is_television_output()
+{
+	return output_device_ == Television || !rgb_input_shader_program_;
+}
+
 void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int output_height, bool only_if_dirty)
 {
 	// lock down any other draw_frames
@@ -91,7 +122,7 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 	// make sure there's a target to draw to
 	if(!framebuffer_ || framebuffer_->get_height() != output_height || framebuffer_->get_width() != output_width)
 	{
-		std::unique_ptr<OpenGL::TextureTarget> new_framebuffer(new OpenGL::TextureTarget((GLsizei)output_width, (GLsizei)output_height, pixel_accumulation_texture_unit));
+		std::unique_ptr<OpenGL::TextureTarget> new_framebuffer(new OpenGL::TextureTarget((GLsizei)output_width, (GLsizei)output_height, pixel_accumulation_texture_unit, GL_LINEAR));
 		if(framebuffer_)
 		{
 			new_framebuffer->bind_framebuffer();
@@ -123,30 +154,29 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 	output_mutex_.unlock();
 
 	struct RenderStage {
-		OpenGL::TextureTarget *const target;
 		OpenGL::Shader *const shader;
+		OpenGL::TextureTarget *const target;
 		float clear_colour[3];
 	};
 
 	// for composite video, go through four steps to get to something that can be painted to the output
 	RenderStage composite_render_stages[] =
 	{
-		{&composite_texture_,	composite_input_shader_program_.get(),				{0.0, 0.0, 0.0}},
-		{&separated_texture_,	composite_separation_filter_program_.get(),			{0.0, 0.5, 0.5}},
-		{&filtered_y_texture_,	composite_y_filter_shader_program_.get(),			{0.0, 0.5, 0.5}},
-		{&filtered_texture_,	composite_chrominance_filter_shader_program_.get(),	{0.0, 0.0, 0.0}},
+		{composite_input_shader_program_.get(),					composite_texture_.get(),		{0.0, 0.0, 0.0}},
+		{composite_separation_filter_program_.get(),			separated_texture_.get(),		{0.0, 0.5, 0.5}},
+		{composite_chrominance_filter_shader_program_.get(),	filtered_texture_.get(),		{0.0, 0.0, 0.0}},
 		{nullptr}
 	};
 
 	// for RGB video, there's only two steps
 	RenderStage rgb_render_stages[] =
 	{
-		{&composite_texture_,	rgb_input_shader_program_.get(),	{0.0, 0.0, 0.0}},
-		{&filtered_texture_,	rgb_filter_shader_program_.get(),	{0.0, 0.0, 0.0}},
+		{rgb_input_shader_program_.get(),	composite_texture_.get(),	{0.0, 0.0, 0.0}},
+		{rgb_filter_shader_program_.get(),	filtered_texture_.get(),	{0.0, 0.0, 0.0}},
 		{nullptr}
 	};
 
-	RenderStage *active_pipeline = (output_device_ == Television || !rgb_input_shader_program_) ? composite_render_stages : rgb_render_stages;
+	RenderStage *active_pipeline = get_is_television_output() ? composite_render_stages : rgb_render_stages;
 
 	if(array_submission.input_size || array_submission.output_size)
 	{
@@ -154,24 +184,39 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 		glBindVertexArray(source_vertex_array_);
 		glDisable(GL_BLEND);
 
-		while(active_pipeline->target)
+#ifdef GL_NV_texture_barrier
+		if(work_texture_)
+		{
+			work_texture_->bind_framebuffer();
+			glClear(GL_COLOR_BUFFER_BIT);
+		}
+#endif
+
+		while(active_pipeline->shader)
 		{
 			// switch to the framebuffer and shader associated with this stage
 			active_pipeline->shader->bind();
-			active_pipeline->target->bind_framebuffer();
 
-			// if this is the final stage before painting to the CRT, clear the framebuffer before drawing in order to blank out
-			// those portions for which no input was provided
-			if(!active_pipeline[1].target)
+			if(!work_texture_)
 			{
-				glClearColor(active_pipeline->clear_colour[0], active_pipeline->clear_colour[1], active_pipeline->clear_colour[2], 1.0f);
-				glClear(GL_COLOR_BUFFER_BIT);
+				active_pipeline->target->bind_framebuffer();
+
+				// if this is the final stage before painting to the CRT, clear the framebuffer before drawing in order to blank out
+				// those portions for which no input was provided
+//				if(!active_pipeline[1].shader)
+//				{
+					glClearColor(active_pipeline->clear_colour[0], active_pipeline->clear_colour[1], active_pipeline->clear_colour[2], 1.0f);
+					glClear(GL_COLOR_BUFFER_BIT);
+//				}
 			}
 
 			// draw
-			glDrawArraysInstanced(GL_LINES, 0, 2, (GLsizei)array_submission.input_size / SourceVertexSize);
+			glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei)array_submission.input_size / SourceVertexSize);
 
 			active_pipeline++;
+#ifdef GL_NV_texture_barrier
+			glTextureBarrierNV();
+#endif
 		}
 
 		// prepare to transfer to framebuffer
@@ -194,6 +239,10 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 		glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei)array_submission.output_size / OutputVertexSize);
 	}
 
+#ifdef GL_NV_texture_barrier
+	glTextureBarrierNV();
+#endif
+
 	// copy framebuffer to the intended place
 	glDisable(GL_BLEND);
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
@@ -211,7 +260,6 @@ void OpenGLOutputBuilder::reset_all_OpenGL_state()
 {
 	composite_input_shader_program_ = nullptr;
 	composite_separation_filter_program_ = nullptr;
-	composite_y_filter_shader_program_ = nullptr;
 	composite_chrominance_filter_shader_program_ = nullptr;
 	rgb_input_shader_program_ = nullptr;
 	rgb_filter_shader_program_ = nullptr;
@@ -229,18 +277,16 @@ void OpenGLOutputBuilder::set_openGL_context_will_change(bool should_delete_reso
 
 void OpenGLOutputBuilder::set_composite_sampling_function(const char *shader)
 {
-	output_mutex_.lock();
+	std::lock_guard<std::mutex> lock_guard(output_mutex_);
 	composite_shader_ = strdup(shader);
 	reset_all_OpenGL_state();
-	output_mutex_.unlock();
 }
 
 void OpenGLOutputBuilder::set_rgb_sampling_function(const char *shader)
 {
-	output_mutex_.lock();
+	std::lock_guard<std::mutex> lock_guard(output_mutex_);
 	rgb_shader_ = strdup(shader);
 	reset_all_OpenGL_state();
-	output_mutex_.unlock();
 }
 
 #pragma mark - Program compilation
@@ -252,16 +298,25 @@ void OpenGLOutputBuilder::prepare_composite_input_shaders()
 	composite_input_shader_program_->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
 
 	composite_separation_filter_program_ = OpenGL::IntermediateShader::make_chroma_luma_separation_shader();
-	composite_separation_filter_program_->set_source_texture_unit(composite_texture_unit);
+	composite_separation_filter_program_->set_source_texture_unit(work_texture_ ? work_texture_unit : composite_texture_unit);
 	composite_separation_filter_program_->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
 
-	composite_y_filter_shader_program_ = OpenGL::IntermediateShader::make_luma_filter_shader();
-	composite_y_filter_shader_program_->set_source_texture_unit(separated_texture_unit);
-	composite_y_filter_shader_program_->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
-
 	composite_chrominance_filter_shader_program_ = OpenGL::IntermediateShader::make_chroma_filter_shader();
-	composite_chrominance_filter_shader_program_->set_source_texture_unit(filtered_y_texture_unit);
+	composite_chrominance_filter_shader_program_->set_source_texture_unit(work_texture_ ? work_texture_unit : separated_texture_unit);
 	composite_chrominance_filter_shader_program_->set_output_size(IntermediateBufferWidth, IntermediateBufferHeight);
+
+	if(work_texture_)
+	{
+		composite_input_shader_program_->set_is_double_height(true, 0.0f, 0.0f);
+		composite_separation_filter_program_->set_is_double_height(true, 0.0f, 0.5f);
+		composite_chrominance_filter_shader_program_->set_is_double_height(true, 0.5f, 0.0f);
+	}
+	else
+	{
+		composite_input_shader_program_->set_is_double_height(false);
+		composite_separation_filter_program_->set_is_double_height(false);
+		composite_chrominance_filter_shader_program_->set_is_double_height(false);
+	}
 }
 
 void OpenGLOutputBuilder::prepare_rgb_input_shaders()
@@ -295,7 +350,9 @@ void OpenGLOutputBuilder::prepare_source_vertex_array()
 void OpenGLOutputBuilder::prepare_output_shader()
 {
 	output_shader_program_ = OpenGL::OutputShader::make_shader("", "texture(texID, srcCoordinatesVarying).rgb", false);
-	output_shader_program_->set_source_texture_unit(filtered_texture_unit);
+	output_shader_program_->set_source_texture_unit(work_texture_ ? work_texture_unit : filtered_texture_unit);
+//	output_shader_program_->set_source_texture_unit(composite_texture_unit);
+	output_shader_program_->set_origin_is_double_height(!!work_texture_);
 }
 
 void OpenGLOutputBuilder::prepare_output_vertex_array()
@@ -319,6 +376,7 @@ void OpenGLOutputBuilder::set_output_device(OutputDevice output_device)
 		composite_src_output_y_ = 0;
 		last_output_width_ = 0;
 		last_output_height_ = 0;
+		set_output_shader_width();
 	}
 }
 
@@ -362,30 +420,58 @@ void OpenGLOutputBuilder::set_colour_space_uniforms()
 	}
 
 	if(composite_input_shader_program_)					composite_input_shader_program_->set_colour_conversion_matrices(fromRGB, toRGB);
+	if(composite_separation_filter_program_)			composite_separation_filter_program_->set_colour_conversion_matrices(fromRGB, toRGB);
 	if(composite_chrominance_filter_shader_program_)	composite_chrominance_filter_shader_program_->set_colour_conversion_matrices(fromRGB, toRGB);
 }
 
+float OpenGLOutputBuilder::get_composite_output_width() const
+{
+	return ((float)colour_cycle_numerator_ * 4.0f) / (float)(colour_cycle_denominator_ * IntermediateBufferWidth);
+}
+
+void OpenGLOutputBuilder::set_output_shader_width()
+{
+	if(output_shader_program_)
+	{
+		const float width = get_is_television_output() ? get_composite_output_width() : 1.0f;
+		output_shader_program_->set_input_width_scaler(width);
+	}
+}
+
 void OpenGLOutputBuilder::set_timing_uniforms()
 {
-	OpenGL::IntermediateShader *intermediate_shaders[] = {
-		composite_input_shader_program_.get(),
-		composite_separation_filter_program_.get(),
-		composite_y_filter_shader_program_.get(),
-		composite_chrominance_filter_shader_program_.get()
-	};
-	bool extends = false;
-	float phaseCyclesPerTick = (float)colour_cycle_numerator_ / (float)(colour_cycle_denominator_ * cycles_per_line_);
-	for(int c = 0; c < 3; c++)
+	const float colour_subcarrier_frequency = (float)colour_cycle_numerator_ / (float)colour_cycle_denominator_;
+	const float output_width = get_composite_output_width();
+	const float sample_cycles_per_line = cycles_per_line_ / output_width;
+
+	if(composite_separation_filter_program_)
 	{
-		if(intermediate_shaders[c]) intermediate_shaders[c]->set_phase_cycles_per_sample(phaseCyclesPerTick, extends);
-		extends = true;
+		composite_separation_filter_program_->set_width_scalers(output_width, output_width);
+		composite_separation_filter_program_->set_separation_frequency(sample_cycles_per_line, colour_subcarrier_frequency);
+		composite_separation_filter_program_->set_extension(6.0f);
+	}
+	if(composite_chrominance_filter_shader_program_)
+	{
+		composite_chrominance_filter_shader_program_->set_width_scalers(output_width, output_width);
+		composite_chrominance_filter_shader_program_->set_extension(5.0f);
+	}
+	if(rgb_filter_shader_program_)
+	{
+		rgb_filter_shader_program_->set_width_scalers(1.0f, 1.0f);
+		rgb_filter_shader_program_->set_filter_coefficients(sample_cycles_per_line, (float)input_frequency_ * 0.5f);
+	}
+	if(output_shader_program_)
+	{
+		set_output_shader_width();
+		output_shader_program_->set_timing(height_of_display_, cycles_per_line_, horizontal_scan_period_, vertical_scan_period_, vertical_period_divider_);
+	}
+	if(composite_input_shader_program_)
+	{
+		composite_input_shader_program_->set_width_scalers(1.0f, output_width);
+		composite_input_shader_program_->set_extension(0.0f);
+	}
+	if(rgb_input_shader_program_)
+	{
+		rgb_input_shader_program_->set_width_scalers(1.0f, 1.0f);
 	}
-
-	if(output_shader_program_) output_shader_program_->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_separation_filter_program_)			composite_separation_filter_program_->set_separation_frequency(cycles_per_line_, colour_subcarrier_frequency);
-	if(composite_y_filter_shader_program_)				composite_y_filter_shader_program_->set_filter_coefficients(cycles_per_line_, colour_subcarrier_frequency * 0.25f);
-	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);
 }

Outputs/CRT/Internals/CRTOpenGL.hpp

@@ -66,13 +66,19 @@ class OpenGLOutputBuilder {
 		GLsizei composite_src_output_y_;
 
 		std::unique_ptr<OpenGL::OutputShader> output_shader_program_;
-		std::unique_ptr<OpenGL::IntermediateShader> composite_input_shader_program_, composite_separation_filter_program_, composite_y_filter_shader_program_, composite_chrominance_filter_shader_program_;
-		std::unique_ptr<OpenGL::IntermediateShader> rgb_input_shader_program_, rgb_filter_shader_program_;
 
-		OpenGL::TextureTarget composite_texture_;	// receives raw composite levels
-		OpenGL::TextureTarget separated_texture_;	// receives unfiltered Y in the R channel plus unfiltered but demodulated chrominance in G and B
-		OpenGL::TextureTarget filtered_y_texture_;	// receives filtered Y in the R channel plus unfiltered chrominance in G and B
-		OpenGL::TextureTarget filtered_texture_;	// receives filtered YIQ or YUV
+		std::unique_ptr<OpenGL::IntermediateShader> composite_input_shader_program_;
+		std::unique_ptr<OpenGL::IntermediateShader> composite_separation_filter_program_;
+		std::unique_ptr<OpenGL::IntermediateShader> composite_chrominance_filter_shader_program_;
+
+		std::unique_ptr<OpenGL::IntermediateShader> rgb_input_shader_program_;
+		std::unique_ptr<OpenGL::IntermediateShader> rgb_filter_shader_program_;
+
+		std::unique_ptr<OpenGL::TextureTarget> composite_texture_;	// receives raw composite levels
+		std::unique_ptr<OpenGL::TextureTarget> separated_texture_;	// receives filtered Y in the R channel plus unfiltered but demodulated chrominance in G and B
+		std::unique_ptr<OpenGL::TextureTarget> filtered_texture_;	// receives filtered YIQ or YUV
+
+		std::unique_ptr<OpenGL::TextureTarget> work_texture_;		// used for all intermediate rendering if texture fences are supported
 
 		std::unique_ptr<OpenGL::TextureTarget> framebuffer_;		// the current pixel output
 
@@ -88,6 +94,9 @@ class OpenGLOutputBuilder {
 		void reset_all_OpenGL_state();
 
 		GLsync fence_;
+		float get_composite_output_width() const;
+		void set_output_shader_width();
+		bool get_is_television_output();
 
 	public:
 		// These two are protected by output_mutex_.

Outputs/CRT/Internals/OpenGL.hpp

@@ -15,6 +15,7 @@
 	#else
 		#include <OpenGL/OpenGL.h>
 		#include <OpenGL/gl3.h>
+		#include <OpenGL/gl3ext.h>
 	#endif
 #endif
 

Outputs/CRT/Internals/Shaders/IntermediateShader.cpp

@@ -40,11 +40,14 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_shader(const char *
 		"in vec2 ends;"
 		"in vec3 phaseTimeAndAmplitude;"
 
-		"uniform float phaseCyclesPerTick;"
 		"uniform ivec2 outputTextureSize;"
 		"uniform float extension;"
 		"uniform %s texID;"
 		"uniform float offsets[5];"
+		"uniform vec2 widthScalers;"
+		"uniform float inputVerticalOffset;"
+		"uniform float outputVerticalOffset;"
+		"uniform float textureHeightDivisor;"
 
 		"out vec2 phaseAndAmplitudeVarying;"
 		"out vec2 inputPositionsVarying[11];"
@@ -53,35 +56,51 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_shader(const char *
 
 		"void main(void)"
 		"{"
+			// odd vertices are on the left, even on the right
 			"float extent = float(gl_VertexID & 1);"
+			"float longitudinal = float((gl_VertexID & 2) >> 1);"
 
-			"vec2 inputPosition = vec2(mix(inputStart.x, ends.x, extent), inputStart.y);"
-			"vec2 outputPosition = vec2(mix(outputStart.x, ends.y, extent), outputStart.y);"
+			// inputPosition.x is either inputStart.x or ends.x, depending on whether it is on the left or the right;
+			// outputPosition.x is either outputStart.x or ends.y;
+			// .ys are inputStart.y and outputStart.y respectively
+			"vec2 inputPosition = vec2(mix(inputStart.x, ends.x, extent)*widthScalers[0], inputStart.y + inputVerticalOffset);"
+			"vec2 outputPosition = vec2(mix(outputStart.x, ends.y, extent)*widthScalers[1], outputStart.y + outputVerticalOffset);"
+
+			"inputPosition.y += longitudinal;"
+			"outputPosition.y += longitudinal;"
+
+			// extension is the amount to extend both the input and output by to add a full colour cycle at each end
 			"vec2 extensionVector = vec2(extension, 0.0) * 2.0 * (extent - 0.5);"
 
+			// extended[Input/Output]Position are [input/output]Position with the necessary applied extension
 			"vec2 extendedInputPosition = %s + extensionVector;"
 			"vec2 extendedOutputPosition = outputPosition + extensionVector;"
 
+			// keep iInputPositionVarying in whole source pixels, scale mappedInputPosition to the ordinary normalised range
 			"vec2 textureSize = vec2(textureSize(texID, 0));"
 			"iInputPositionVarying = extendedInputPosition;"
-			"vec2 mappedInputPosition = (extendedInputPosition + vec2(0.0, 0.5)) / textureSize;"
+			"vec2 mappedInputPosition = extendedInputPosition / textureSize;"	//  + vec2(0.0, 0.5)
 
-			"inputPositionsVarying[0] = mappedInputPosition - (vec2(offsets[0], 0.0) / textureSize);"
-			"inputPositionsVarying[1] = mappedInputPosition - (vec2(offsets[1], 0.0) / textureSize);"
-			"inputPositionsVarying[2] = mappedInputPosition - (vec2(offsets[2], 0.0) / textureSize);"
-			"inputPositionsVarying[3] = mappedInputPosition - (vec2(offsets[3], 0.0) / textureSize);"
-			"inputPositionsVarying[4] = mappedInputPosition - (vec2(offsets[4], 0.0) / textureSize);"
+			// setup input positions spaced as per the supplied offsets; these are for filtering where required
+			"inputPositionsVarying[0] = mappedInputPosition - (vec2(5.0, 0.0) / textureSize);"
+			"inputPositionsVarying[1] = mappedInputPosition - (vec2(4.0, 0.0) / textureSize);"
+			"inputPositionsVarying[2] = mappedInputPosition - (vec2(3.0, 0.0) / textureSize);"
+			"inputPositionsVarying[3] = mappedInputPosition - (vec2(2.0, 0.0) / textureSize);"
+			"inputPositionsVarying[4] = mappedInputPosition - (vec2(1.0, 0.0) / textureSize);"
 			"inputPositionsVarying[5] = mappedInputPosition;"
-			"inputPositionsVarying[6] = mappedInputPosition + (vec2(offsets[4], 0.0) / textureSize);"
-			"inputPositionsVarying[7] = mappedInputPosition + (vec2(offsets[3], 0.0) / textureSize);"
-			"inputPositionsVarying[8] = mappedInputPosition + (vec2(offsets[2], 0.0) / textureSize);"
-			"inputPositionsVarying[9] = mappedInputPosition + (vec2(offsets[1], 0.0) / textureSize);"
-			"inputPositionsVarying[10] = mappedInputPosition + (vec2(offsets[0], 0.0) / textureSize);"
+			"inputPositionsVarying[6] = mappedInputPosition + (vec2(1.0, 0.0) / textureSize);"
+			"inputPositionsVarying[7] = mappedInputPosition + (vec2(2.0, 0.0) / textureSize);"
+			"inputPositionsVarying[8] = mappedInputPosition + (vec2(3.0, 0.0) / textureSize);"
+			"inputPositionsVarying[9] = mappedInputPosition + (vec2(4.0, 0.0) / textureSize);"
+			"inputPositionsVarying[10] = mappedInputPosition + (vec2(5.0, 0.0) / textureSize);"
 			"delayLinePositionVarying = mappedInputPosition - vec2(0.0, 1.0);"
 
-			"phaseAndAmplitudeVarying.x = (phaseCyclesPerTick * (extendedOutputPosition.x - phaseTimeAndAmplitude.y) + (phaseTimeAndAmplitude.x / 256.0)) * 2.0 * 3.141592654;"
+			// setup phaseAndAmplitudeVarying.x as colour burst subcarrier phase, in radians;
+			// setup phaseAndAmplitudeVarying.x as colour burst amplitude
+			"phaseAndAmplitudeVarying.x = (extendedOutputPosition.x + (phaseTimeAndAmplitude.x / 64.0)) * 0.5 * 3.141592654;"
 			"phaseAndAmplitudeVarying.y = 0.33;" // TODO: reinstate connection with (phaseTimeAndAmplitude.y/256.0)
 
+			// determine output position by scaling the output position according to the texture size
 			"vec2 eyePosition = 2.0*(extendedOutputPosition / outputTextureSize) - vec2(1.0) + vec2(1.0)/outputTextureSize;"
 			"gl_Position = vec4(eyePosition, 0.0, 1.0);"
 		"}", sampler_type, input_variable);
@@ -172,7 +191,6 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_luma_separat
 
 		"in vec2 phaseAndAmplitudeVarying;"
 		"in vec2 inputPositionsVarying[11];"
-		"uniform vec4 weights[3];"
 
 		"out vec3 fragColour;"
 
@@ -180,37 +198,20 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_luma_separat
 
 		"void main(void)"
 		"{"
-			"vec4 samples[3] = vec4[]("
-				"vec4("
-					"texture(texID, inputPositionsVarying[0]).r,"
-					"texture(texID, inputPositionsVarying[1]).r,"
-					"texture(texID, inputPositionsVarying[2]).r,"
-					"texture(texID, inputPositionsVarying[3]).r"
-				"),"
-				"vec4("
-					"texture(texID, inputPositionsVarying[4]).r,"
-					"texture(texID, inputPositionsVarying[5]).r,"
-					"texture(texID, inputPositionsVarying[6]).r,"
-					"texture(texID, inputPositionsVarying[7]).r"
-				"),"
-				"vec4("
-					"texture(texID, inputPositionsVarying[8]).r,"
-					"texture(texID, inputPositionsVarying[9]).r,"
-					"texture(texID, inputPositionsVarying[10]).r,"
-					"0.0"
-				")"
+			"vec4 samples = vec4("
+				"texture(texID, inputPositionsVarying[3]).r,"
+				"texture(texID, inputPositionsVarying[4]).r,"
+				"texture(texID, inputPositionsVarying[5]).r,"
+				"texture(texID, inputPositionsVarying[6]).r"
 			");"
+			"float luminance = dot(samples, vec4(0.25));"
 
-			"float luminance = "
-				"dot(vec3("
-					"dot(samples[0], weights[0]),"
-					"dot(samples[1], weights[1]),"
-					"dot(samples[2], weights[2])"
-				"), vec3(1.0));"
-
-			"float chrominance = 0.5 * (samples[1].y - luminance) / phaseAndAmplitudeVarying.y;"
+			// define chroma to be whatever was here, minus luma
+			"float chrominance = 0.5 * (samples.z - luminance) / phaseAndAmplitudeVarying.y;"
 			"luminance /= (1.0 - phaseAndAmplitudeVarying.y);"
 
+			// split choma colours here, as the most direct place, writing out
+			// RGB = (luma, chroma.x, chroma.y)
 			"vec2 quadrature = vec2(cos(phaseAndAmplitudeVarying.x), -sin(phaseAndAmplitudeVarying.x));"
 			"fragColour = vec3(luminance, vec2(0.5) + (chrominance * quadrature));"
 		"}",false, false);
@@ -232,41 +233,18 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_filter_shade
 		"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"
+				"texture(texID, inputPositionsVarying[6]).rgb"
 			");"
 
-			"vec4 chromaChannel1[] = 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 chromaChannel2[] = 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)"
-			");"
+			"vec4 chromaChannel1 = vec4(samples[0].g, samples[1].g, samples[2].g, samples[3].g);"
+			"vec4 chromaChannel2 = vec4(samples[0].b, samples[1].b, samples[2].b, samples[3].b);"
 
-			"vec3 lumaChromaColour = vec3(samples[5].r,"
-				"dot(vec3("
-					"dot(chromaChannel1[0], weights[0]),"
-					"dot(chromaChannel1[1], weights[1]),"
-					"dot(chromaChannel1[2], weights[2])"
-				"), vec3(1.0)),"
-				"dot(vec3("
-					"dot(chromaChannel2[0], weights[0]),"
-					"dot(chromaChannel2[1], weights[1]),"
-					"dot(chromaChannel2[2], weights[2])"
-				"), vec3(1.0))"
+			"vec3 lumaChromaColour = vec3(samples[2].r,"
+				"dot(chromaChannel1, vec4(0.25)),"
+				"dot(chromaChannel2, vec4(0.25))"
 			");"
 
 			"vec3 lumaChromaColourInRange = (lumaChromaColour - vec3(0.0, 0.5, 0.5)) * vec3(1.0, 2.0, 2.0);"
@@ -274,52 +252,6 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_filter_shade
 		"}", false, false);
 }
 
-std::unique_ptr<IntermediateShader> IntermediateShader::make_luma_filter_shader()
-{
-	return make_shader(
-		"#version 150\n"
-
-		"in vec2 inputPositionsVarying[11];"
-		"uniform vec4 weights[3];"
-
-		"out vec3 fragColour;"
-
-		"uniform sampler2D texID;"
-		"uniform mat3 lumaChromaToRGB;"
-
-		"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 luminance[] = 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)"
-			");"
-
-			"fragColour = vec3("
-				"dot(vec3("
-					"dot(luminance[0], weights[0]),"
-					"dot(luminance[1], weights[1]),"
-					"dot(luminance[2], weights[2])"
-				"), vec3(1.0)),"
-				"samples[5].gb"
-			");"
-		"}", false, false);
-}
-
 std::unique_ptr<IntermediateShader> IntermediateShader::make_rgb_filter_shader()
 {
 	return make_shader(
@@ -404,44 +336,53 @@ void IntermediateShader::set_filter_coefficients(float sampling_rate, float cuto
 	// Perform a linear search for the highest number of taps we can use with 11 samples.
 	GLfloat weights[12];
 	GLfloat offsets[5];
-	unsigned int taps = 21;
+	unsigned int taps = 11;
+//	unsigned int taps = 21;
 	while(1)
 	{
 		float coefficients[21];
 		SignalProcessing::FIRFilter luminance_filter(taps, sampling_rate, 0.0f, cutoff_frequency, SignalProcessing::FIRFilter::DefaultAttenuation);
 		luminance_filter.get_coefficients(coefficients);
 
-		int sample = 0;
-		int c = 0;
+//		int sample = 0;
+//		int c = 0;
 		memset(weights, 0, sizeof(float)*12);
 		memset(offsets, 0, sizeof(float)*5);
 
 		int halfSize = (taps >> 1);
-		while(c < halfSize && sample < 5)
+		for(int c = 0; c < taps; c++)
 		{
-			offsets[sample] = (float)(halfSize - c);
-			if((coefficients[c] < 0.0f) == (coefficients[c+1] < 0.0f) && c+1 < (taps >> 1))
-			{
-				weights[sample] = coefficients[c] + coefficients[c+1];
-				offsets[sample] -= (coefficients[c+1] / weights[sample]);
-				c += 2;
-			}
-			else
-			{
-				weights[sample] = coefficients[c];
-				c++;
-			}
-			sample ++;
-		}
-		if(c == halfSize)	// i.e. we finished combining inputs before we ran out of space
-		{
-			weights[sample] = coefficients[c];
-			for(int c = 0; c < sample; c++)
-			{
-				weights[sample+c+1] = weights[sample-c-1];
-			}
-			break;
+			if(c < 5) offsets[c] = (halfSize - c);
+			weights[c] = coefficients[c];
 		}
+		break;
+
+//		int halfSize = (taps >> 1);
+//		while(c < halfSize && sample < 5)
+//		{
+//			offsets[sample] = (float)(halfSize - c);
+//			if((coefficients[c] < 0.0f) == (coefficients[c+1] < 0.0f) && c+1 < (taps >> 1))
+//			{
+//				weights[sample] = coefficients[c] + coefficients[c+1];
+//				offsets[sample] -= (coefficients[c+1] / weights[sample]);
+//				c += 2;
+//			}
+//			else
+//			{
+//				weights[sample] = coefficients[c];
+//				c++;
+//			}
+//			sample ++;
+//		}
+//		if(c == halfSize)	// i.e. we finished combining inputs before we ran out of space
+//		{
+//			weights[sample] = coefficients[c];
+//			for(int c = 0; c < sample; c++)
+//			{
+//				weights[sample+c+1] = weights[sample-c-1];
+//			}
+//			break;
+//		}
 		taps -= 2;
 	}
 
@@ -454,10 +395,9 @@ void IntermediateShader::set_separation_frequency(float sampling_rate, float col
 	set_filter_coefficients(sampling_rate, colour_burst_frequency);
 }
 
-void IntermediateShader::set_phase_cycles_per_sample(float phase_cycles_per_sample, bool extend_runs_to_full_cycle)
+void IntermediateShader::set_extension(float extension)
 {
-	set_uniform("phaseCyclesPerTick", (GLfloat)phase_cycles_per_sample);
-	set_uniform("extension", extend_runs_to_full_cycle ? ceilf(1.0f / phase_cycles_per_sample) : 0.0f);
+	set_uniform("extension", extension);
 }
 
 void IntermediateShader::set_colour_conversion_matrices(float *fromRGB, float *toRGB)
@@ -465,3 +405,15 @@ void IntermediateShader::set_colour_conversion_matrices(float *fromRGB, float *t
 	set_uniform_matrix("lumaChromaToRGB", 3, false, toRGB);
 	set_uniform_matrix("rgbToLumaChroma", 3, false, fromRGB);
 }
+
+void IntermediateShader::set_width_scalers(float input_scaler, float output_scaler)
+{
+	set_uniform("widthScalers", input_scaler, output_scaler);
+}
+
+void IntermediateShader::set_is_double_height(bool is_double_height, float input_offset, float output_offset)
+{
+	set_uniform("textureHeightDivisor", is_double_height ? 2.0f : 1.0f);
+	set_uniform("inputVerticalOffset", input_offset);
+	set_uniform("outputVerticalOffset", output_offset);
+}

Outputs/CRT/Internals/Shaders/IntermediateShader.hpp

@@ -44,11 +44,6 @@ public:
 	*/
 	static std::unique_ptr<IntermediateShader> make_chroma_filter_shader();
 
-	/*!
-		Constructs and returns an intermediate shader that will filter R while passing through G and B unchanged.
-	*/
-	static std::unique_ptr<IntermediateShader> make_luma_filter_shader();
-
 	/*!
 		Constructs and returns an intermediate shader that will filter R, G and B.
 	*/
@@ -81,13 +76,24 @@ public:
 		geometry should be extended so that a complete colour cycle is included at both the beginning and end,
 		to occur upon the next `bind`.
 	*/
-	void set_phase_cycles_per_sample(float phase_cycles_per_sample, bool extend_runs_to_full_cycle);
+	void set_extension(float extension);
 
 	/*!
 		Queues setting the matrices that convert between RGB and chrominance/luminance to occur on the next `bind`.
 	*/
 	void set_colour_conversion_matrices(float *fromRGB, float *toRGB);
 
+	/*!
+		Sets the proportions of the input and output areas that should be considered the whole width — 1.0 means use all available
+		space, 0.5 means use half, etc.
+	*/
+	void set_width_scalers(float input_scaler, float output_scaler);
+
+	/*!
+		Sets source and target vertical offsets.
+	*/
+	void set_is_double_height(bool is_double_height, float input_offset = 0.0f, float output_offset = 0.0f);
+
 private:
 	static std::unique_ptr<IntermediateShader> make_shader(const char *fragment_shader, bool use_usampler, bool input_is_inputPosition);
 };

Outputs/CRT/Internals/Shaders/OutputShader.cpp

@@ -38,6 +38,8 @@ std::unique_ptr<OutputShader> OutputShader::make_shader(const char *fragment_met
 		"uniform vec2 positionConversion;"
 		"uniform vec2 scanNormal;"
 		"uniform %s texID;"
+		"uniform float inputScaler;"
+		"uniform int textureHeightDivisor;"
 
 		"out float lateralVarying;"
 		"out vec2 srcCoordinatesVarying;"
@@ -52,9 +54,10 @@ std::unique_ptr<OutputShader> OutputShader::make_shader(const char *fragment_met
 			"lateralVarying = lateral - 0.5;"
 
 			"vec2 vSrcCoordinates = vec2(x, vertical.y);"
-			"ivec2 textureSize = textureSize(texID, 0);"
+			"ivec2 textureSize = textureSize(texID, 0) * ivec2(1, textureHeightDivisor);"
 			"iSrcCoordinatesVarying = vSrcCoordinates;"
-			"srcCoordinatesVarying = vec2(vSrcCoordinates.x / textureSize.x, (vSrcCoordinates.y + 0.5) / textureSize.y);"
+			"srcCoordinatesVarying = vec2(inputScaler * vSrcCoordinates.x / textureSize.x, (vSrcCoordinates.y + 0.5) / textureSize.y);"
+			"srcCoordinatesVarying.x = srcCoordinatesVarying.x - mod(srcCoordinatesVarying.x, 1.0 / textureSize.x);"
 
 			"vec2 vPosition = vec2(x, vertical.x);"
 			"vec2 floatingPosition = (vPosition / positionConversion) + lateral * scanNormal;"
@@ -117,3 +120,13 @@ void OutputShader::set_timing(unsigned int height_of_display, unsigned int cycle
 	set_uniform("scanNormal", scan_normal[0], scan_normal[1]);
 	set_uniform("positionConversion", (GLfloat)horizontal_scan_period, (GLfloat)vertical_scan_period / (GLfloat)vertical_period_divider);
 }
+
+void OutputShader::set_input_width_scaler(float input_scaler)
+{
+	set_uniform("inputScaler", input_scaler);
+}
+
+void OutputShader::set_origin_is_double_height(bool is_double_height)
+{
+	set_uniform("textureHeightDivisor", is_double_height ? 2 : 1);
+}

Outputs/CRT/Internals/Shaders/OutputShader.hpp

@@ -58,6 +58,16 @@ public:
 		to occur upon the next `bind`.
 	*/
 	void set_timing(unsigned int height_of_display, unsigned int cycles_per_line, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider);
+
+	/*!
+	*/
+	void set_origin_is_double_height(bool is_double_height);
+
+	/*!
+		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.
+	*/
+	void set_input_width_scaler(float input_scaler);
 };
 
 }

Outputs/CRT/Internals/Shaders/Shader.cpp

@@ -156,7 +156,8 @@ void Shader::set_uniform(const std::string &name, GLint value1, GLint value2)
 void Shader::set_uniform(const std::string &name, GLfloat value1, GLfloat value2)
 {
 	enqueue_function([name, value1, value2, this] {
-		glUniform2f(location(), value1, value2);
+		GLint location = location();
+		glUniform2f(location, value1, value2);
 	});
 }
 

Outputs/CRT/Internals/TextureTarget.cpp

@@ -12,7 +12,7 @@
 
 using namespace OpenGL;
 
-TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit) :
+TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit, GLint mag_filter) :
 	_width(width),
 	_height(height),
 	_pixel_shader(nullptr),
@@ -33,8 +33,8 @@ TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit)
 	uint8_t *blank_buffer = (uint8_t *)calloc((size_t)(_expanded_width * _expanded_height), 4);
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)_expanded_width, (GLsizei)_expanded_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, blank_buffer);
 	free(blank_buffer);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 
 	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, _texture, 0);
 

Outputs/CRT/Internals/TextureTarget.hpp

@@ -30,7 +30,7 @@ class TextureTarget {
 			@param height The height of target to create.
 			@param texture_unit A texture unit on which to bind the texture.
 		*/
-		TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit);
+		TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit, GLint mag_filter);
 		~TextureTarget();
 
 		/*!

README.md

@@ -24,12 +24,22 @@ The full process of loading a title — even if you've never used the emulated m
 
 ## Signal Processing
 
-Consider an ordinary, unmodified Commodore Vic-20. Its only video output is composite. Therefore the emulated machine's only video output is composite. In order to display the video output, your GPU then decodes composite video. Therefore all composite video artefacts are present and exactly correct, not because of a posthoc filter combining all the subjective effects that this author associates with composite video but because the real signal is really being processed.
+Consider an ordinary, unmodified Commodore Vic-20. Its only video output is composite. Therefore the emulated machine's only video output is composite. In order to display the video output, your GPU then decodes composite video. Therefore all composite video artefacts are present and exactly correct, not because of a post hoc filter combining all the subjective effects that this author associates with composite video but because the real signal is really being processed.
 
 Similar effort is put into audio generation. If the real machine normally generates audio at 192Khz then the emulator generates a 192Khz source signal and filters it down to whatever the host machine can output.
 
 If your machine has a 4k monitor and a 96Khz audio output? Then you'll get a 4k rendering of a composite display and, assuming the emulated machine produces source audio at or above 96Khz, 96,000 individual distinct audio samples a second. Interlaced video also works and looks much as it always did on those machines that produce it.
 
+### Samples
+
+| 1:1 Pixel Copying | Composite Decoded |
+|---|---|
+|![The Electron start screen, with a classic 1:1 pixel emulation](READMEImages/NaiveElectron.png)|![The Electron start screen, decoded from an interlaced composite feed](READMEImages/CompositeElectron.png)|
+|![Repton 3 in game, with a classic 1:1 pixel emulation](READMEImages/NaiveRepton3.png)|![Repton 3 in game, decoded from an interlaced composite feed](READMEImages/CompositeRepton3.png)|
+|![Stormlord with a classic 1:1 pixel emulation](READMEImages/NaiveStormlord.png)|![Stormlord decoded from an interlaced composite feed](READMEImages/CompositeStormlord.png)|
+
+<img src="READMEImages/ReptonInterlaced.gif" height=600 alt="Repton title screen, interlaced">
+
 ## Low Latency
 
 The display produced is an emulated CRT, with phosphor decay. Therefore if you have a 140Hz monitor it can produce 140 distinct frames per second. Latency is dictated by the output hardware, not the emulated machine.

StaticAnalyser/Acorn/StaticAnalyser.cpp

@@ -69,7 +69,7 @@ void StaticAnalyser::Acorn::AddTargets(
 	target.probability = 1.0; // TODO: a proper estimation
 	target.acorn.has_dfs = false;
 	target.acorn.has_adfs = false;
-	target.acorn.should_hold_shift = false;
+	target.acorn.should_shift_restart = false;
 
 	// strip out inappropriate cartridges
 	target.cartridges = AcornCartridgesFrom(cartridges);
@@ -126,20 +126,11 @@ void StaticAnalyser::Acorn::AddTargets(
 			target.acorn.has_dfs = !!dfs_catalogue;
 			target.acorn.has_adfs = !!adfs_catalogue;
 
-			std::string adfs_command;
 			Catalogue::BootOption bootOption = (dfs_catalogue ?: adfs_catalogue)->bootOption;
-			switch(bootOption)
-			{
-				case Catalogue::BootOption::None:		adfs_command = "*CAT\n";		break;
-				case Catalogue::BootOption::LoadBOOT:	adfs_command = "*LOAD !BOOT\n";	break;
-				case Catalogue::BootOption::RunBOOT:	adfs_command = "*RUN !BOOT\n";	break;
-				case Catalogue::BootOption::ExecBOOT:	adfs_command = "*EXEC !BOOT\n";	break;
-			}
-
-//			if(target.acorn.has_dfs && bootOption != Catalogue::BootOption::None)
-//				target.acorn.should_hold_shift = true;
-//			else
-				target.loadingCommand = (target.acorn.has_dfs ? "" : "*MOUNT\n") + adfs_command;
+			if(bootOption != Catalogue::BootOption::None)
+				target.acorn.should_shift_restart = true;
+			else
+				target.loadingCommand = "*CAT\n";
 		}
 	}
 

StaticAnalyser/StaticAnalyser.hpp

@@ -47,7 +47,7 @@ struct Target {
 		struct {
 			bool has_adfs;
 			bool has_dfs;
-			bool should_hold_shift;
+			bool should_shift_restart;
 		} acorn;
 
 		struct {