From 986c4006a664b6d05ad334ec33387a68cdfabf58 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 20 Mar 2021 23:45:49 -0400
Subject: [PATCH] Corrected: PAL machines can now be overt in terms of odd/even
 colour burst.

---
 Outputs/CRT/CRT.cpp | 9 +++++----
 Outputs/CRT/CRT.hpp | 4 ++--
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/Outputs/CRT/CRT.cpp b/Outputs/CRT/CRT.cpp
index c72d98a39..ad1d3cf1c 100644
--- a/Outputs/CRT/CRT.cpp
+++ b/Outputs/CRT/CRT.cpp
@@ -32,7 +32,7 @@ void CRT::set_new_timing(int cycles_per_line, int height_of_display, Outputs::Di
 	phase_numerator_ = 0;
 	colour_cycle_numerator_ = int64_t(colour_cycle_numerator);
 	phase_alternates_ = should_alternate;
-	is_alernate_line_ &= phase_alternates_;
+	should_be_alternate_line_ &= phase_alternates_;
 	cycles_per_line_ = cycles_per_line;
 	const int multiplied_cycles_per_line = cycles_per_line * time_multiplier_;
 
@@ -275,7 +275,7 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_
 
 			// If retrace is starting, update phase if required and mark no colour burst spotted yet.
 			if(next_horizontal_sync_event == Flywheel::SyncEvent::StartRetrace) {
-				is_alernate_line_ ^= phase_alternates_;
+				should_be_alternate_line_ ^= phase_alternates_;
 				colour_burst_amplitude_ = 0;
 			}
 		}
@@ -408,18 +408,19 @@ void CRT::output_level(int number_of_cycles) {
 	output_scan(&scan);
 }
 
-void CRT::output_colour_burst(int number_of_cycles, uint8_t phase, uint8_t amplitude) {
+void CRT::output_colour_burst(int number_of_cycles, uint8_t phase, bool is_alternate_line, uint8_t amplitude) {
 	Scan scan;
 	scan.type = Scan::Type::ColourBurst;
 	scan.number_of_cycles = number_of_cycles;
 	scan.phase = phase;
 	scan.amplitude = amplitude >> 1;
+	is_alernate_line_ = is_alternate_line;
 	output_scan(&scan);
 }
 
 void CRT::output_default_colour_burst(int number_of_cycles, uint8_t amplitude) {
 	// TODO: avoid applying a rounding error here?
-	output_colour_burst(number_of_cycles, uint8_t((phase_numerator_ * 256) / phase_denominator_), amplitude);
+	output_colour_burst(number_of_cycles, uint8_t((phase_numerator_ * 256) / phase_denominator_), should_be_alternate_line_, amplitude);
 }
 
 void CRT::set_immediate_default_phase(float phase) {
diff --git a/Outputs/CRT/CRT.hpp b/Outputs/CRT/CRT.hpp
index 7ab9dbcf5..9749d5011 100644
--- a/Outputs/CRT/CRT.hpp
+++ b/Outputs/CRT/CRT.hpp
@@ -61,7 +61,7 @@ class CRT {
 		int64_t phase_denominator_ = 1;
 		int64_t phase_numerator_ = 0;
 		int64_t colour_cycle_numerator_ = 1;
-		bool is_alernate_line_ = false, phase_alternates_ = false;
+		bool is_alernate_line_ = false, phase_alternates_ = false, should_be_alternate_line_ = false;
 
 		void advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_requested, const Scan::Type type, int number_of_samples);
 		Flywheel::SyncEvent get_next_vertical_sync_event(bool vsync_is_requested, int cycles_to_run_for, int *cycles_advanced);
@@ -207,7 +207,7 @@ class CRT {
 			@param amplitude The amplitude of the colour burst in 1/255ths of the amplitude of the
 			positive portion of the wave.
 		*/
-		void output_colour_burst(int number_of_cycles, uint8_t phase, uint8_t amplitude = DefaultAmplitude);
+		void output_colour_burst(int number_of_cycles, uint8_t phase, bool is_alternate_line = false, uint8_t amplitude = DefaultAmplitude);
 
 		/*! Outputs a colour burst exactly in phase with CRT expectations using the idiomatic amplitude.