From 01109d441b0e79b16d3fe52bf2fe2104ce7a39c5 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 27 Jul 2015 19:04:03 -0400
Subject: [PATCH] Made an attempt at NTSC colours. Hard coded in RGB, not
 composite. Short cuts, tsk.

---
 Machines/Atari2600.cpp                        | 37 +++++++++++++------
 Machines/Atari2600.hpp                        |  6 ++-
 .../Mac/Clock Signal/CSCathodeRayView.m       |  2 +-
 Outputs/CRT.cpp                               |  2 +-
 4 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/Machines/Atari2600.cpp b/Machines/Atari2600.cpp
index b81c4c986..9a9d15fa0 100644
--- a/Machines/Atari2600.cpp
+++ b/Machines/Atari2600.cpp
@@ -28,18 +28,28 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
 {
 	// get the playfield pixel
 	const int x = offset >> 2;
-	const int mirrored = (x / 20) & (_playFieldControl&1);
+	const int mirrored = (x / 20) & (_playfieldControl&1);
 	const int index = mirrored ? x - 20 : 19 - (x%20);
 	const int byte = 2 - (index >> 3);
 	const int lowestBit = (byte&1)^1;
 	const int bit = (index & 7)^(lowestBit | (lowestBit << 1) | (lowestBit << 2));
 
-	uint8_t playFieldPixel = (_playField[byte] >> bit)&1;
+	uint8_t playFieldPixel = (_playfield[byte] >> bit)&1;
+
+	const uint8_t palette[16][3] =
+	{
+		{255, 255, 255},	{253, 250, 115},	{236, 199, 125},	{252, 187, 151},
+		{252, 180, 181},	{235, 177, 223},	{211, 178, 250},	{187, 182, 250},
+		{164, 186, 250},	{166, 201, 250},	{164, 224, 251},	{165, 251, 213},
+		{185, 251, 187},	{201, 250, 168},	{225, 235, 160},	{252, 223, 145}
+	};
 
 	// TODO: almost everything!
-	pixel[0] = playFieldPixel ? 0xff : 0x00;
-	pixel[1] = playFieldPixel ? 0xff : 0x00;
-	pixel[2] = playFieldPixel ? 0xff : 0x00;
+	uint8_t outputColour = playFieldPixel ? _playfieldColour : _backgroundColour;
+	pixel[0] = palette[outputColour >> 4][0];
+	pixel[1] = palette[outputColour >> 4][1];
+	pixel[2] = palette[outputColour >> 4][2];
+	pixel[3] = (outputColour & 14) << 4;
 }
 
 void Machine::output_pixels(int count)
@@ -63,7 +73,7 @@ void Machine::output_pixels(int count)
 				if(_vBlankEnabled) {
 					output_state(OutputState::Blank, nullptr);
 				} else {
-					uint8_t outputPixel[3];
+					uint8_t outputPixel[4];
 					get_output_pixel(outputPixel, 159 - _horizontalTimer);
 					output_state(OutputState::Pixel, outputPixel);
 				}
@@ -104,7 +114,7 @@ void Machine::output_state(OutputState state, uint8_t *pixel)
 		_outputBuffer[(_lastOutputStateDuration * 4) + 0] = pixel[0];
 		_outputBuffer[(_lastOutputStateDuration * 4) + 1] = pixel[1];
 		_outputBuffer[(_lastOutputStateDuration * 4) + 2] = pixel[2];
-		_outputBuffer[(_lastOutputStateDuration * 4) + 3] = 0xff;
+		_outputBuffer[(_lastOutputStateDuration * 4) + 3] = pixel[3];
 	}
 }
 
@@ -147,10 +157,15 @@ int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t add
 				} break;
 				case 3: _horizontalTimer = 227; break;
 
-				case 0x0a: _playFieldControl = *value; break;
-				case 0x0d: _playField[0] = *value; break;
-				case 0x0e: _playField[1] = *value; break;
-				case 0x0f: _playField[2] = *value; break;
+				case 0x06: _player0Colour = *value;		break;
+				case 0x07: _player1Colour = *value;		break;
+				case 0x08: _playfieldColour = *value;	break;
+				case 0x09: _backgroundColour = *value;	break;
+
+				case 0x0a: _playfieldControl = *value;	break;
+				case 0x0d: _playfield[0] = *value;		break;
+				case 0x0e: _playfield[1] = *value;		break;
+				case 0x0f: _playfield[2] = *value;		break;
 			}
 		}
 //		printf("Uncaught TIA %04x\n", address);
diff --git a/Machines/Atari2600.hpp b/Machines/Atari2600.hpp
index 69be8cd9b..61443f9cd 100644
--- a/Machines/Atari2600.hpp
+++ b/Machines/Atari2600.hpp
@@ -38,7 +38,11 @@ class Machine: public CPU6502::Processor<Machine> {
 		unsigned int _piaTimerShift;
 
 		// graphics registers
-		uint8_t _playField[3], _playFieldControl;
+		uint8_t _playfield[3], _playfieldControl;
+		uint8_t _player0Colour;
+		uint8_t _player1Colour;
+		uint8_t _playfieldColour;
+		uint8_t _backgroundColour;
 
 		// graphics output
 		int32_t _horizontalTimer;
diff --git a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m
index 5d28f0e48..0231a64b4 100644
--- a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
+++ b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
@@ -49,7 +49,7 @@
 	CVDisplayLinkStart(displayLink);
 
 	glEnable(GL_BLEND);
-	glBlendFunc(GL_ONE, GL_ONE);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE);
 }
 
 static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp *now, const CVTimeStamp *outputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut, void *displayLinkContext)
diff --git a/Outputs/CRT.cpp b/Outputs/CRT.cpp
index 04ef64c36..c97fdc2e1 100644
--- a/Outputs/CRT.cpp
+++ b/Outputs/CRT.cpp
@@ -54,7 +54,7 @@ CRT::CRT(int cycles_per_line, int height_of_display, int number_of_buffers, ...)
 
 	// width should be 1.0 / _height_of_display, rotated to match the direction
 	float angle = atan2f(scanSpeedYfl, scanSpeedXfl);
-	float halfLineWidth = (float)_height_of_display * 1.9f;
+	float halfLineWidth = (float)_height_of_display * 2.0f;
 	_widths[0][0] = (sinf(angle) / halfLineWidth) * UINT32_MAX;
 	_widths[0][1] = (cosf(angle) / halfLineWidth) * UINT32_MAX;