Adds first_scan to LineMetadata.

Also reorders `Line` fields to match `Scan` fields, just for visual consistency.

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

@@ -5113,6 +5113,7 @@
 				);
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_OPTIMIZATION_LEVEL = 2;
+				GCC_PREPROCESSOR_DEFINITIONS = NDEBUG;
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};

OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm

@@ -142,6 +142,8 @@ using BufferingScanTarget = Outputs::Display::BufferingScanTarget;
 		_frameBufferRenderPass.colorAttachments[0].texture = _frameBuffer;
 		_frameBufferRenderPass.colorAttachments[0].loadAction = MTLLoadActionLoad;
 		_frameBufferRenderPass.colorAttachments[0].storeAction = MTLStoreActionStore;
+
+		// TODO: old framebuffer should be resized onto the new one.
 	}
 }
 

OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal

@@ -45,12 +45,12 @@ struct Scan {
 struct Line {
 	struct EndPoint {
 		uint16_t position[2];
-		uint16_t cyclesSinceRetrace;
 		uint16_t compositeAngle;
+		uint16_t cyclesSinceRetrace;
 	} endPoints[2];
 
-	uint16_t line;
 	uint8_t compositeAmplitude;
+	uint16_t line;
 };
 
 // MARK: - Intermediate structs.

Outputs/ScanTargets/BufferingScanTarget.cpp

@@ -131,19 +131,19 @@ Outputs::Display::ScanTarget::Scan *BufferingScanTarget::begin_scan() {
 		return nullptr;
 	}
 
-	const auto result = &scan_buffer_[write_pointers_.scan_buffer];
+	const auto result = &scan_buffer_[write_pointers_.scan];
 	const auto read_pointers = read_pointers_.load(std::memory_order::memory_order_relaxed);
 
 	// Advance the pointer.
-	const auto next_write_pointer = decltype(write_pointers_.scan_buffer)((write_pointers_.scan_buffer + 1) % scan_buffer_size_);
+	const auto next_write_pointer = decltype(write_pointers_.scan)((write_pointers_.scan + 1) % scan_buffer_size_);
 
 	// Check whether that's too many.
-	if(next_write_pointer == read_pointers.scan_buffer) {
+	if(next_write_pointer == read_pointers.scan) {
 		allocation_has_failed_ = true;
 		vended_scan_ = nullptr;
 		return nullptr;
 	}
-	write_pointers_.scan_buffer = next_write_pointer;
+	write_pointers_.scan = next_write_pointer;
 	++provided_scans_;
 
 	// Fill in extra OpenGL-specific details.
@@ -211,12 +211,18 @@ void BufferingScanTarget::announce(Event event, bool is_visible, const Outputs::
 	} else {
 		// Commit the most recent line only if any scans fell on it and all allocation was successful.
 		if(!allocation_has_failed_ && provided_scans_) {
+			const auto submit_pointers = submit_pointers_.load(std::memory_order::memory_order_relaxed);
+
 			// Store metadata.
 			LineMetadata &metadata = line_metadata_buffer_[size_t(write_pointers_.line)];
 			metadata.is_first_in_frame = is_first_in_frame_;
 			metadata.previous_frame_was_complete = previous_frame_was_complete_;
+			metadata.first_scan = submit_pointers.scan;
 			is_first_in_frame_ = false;
 
+			// Sanity check.
+			assert(((metadata.first_scan + provided_scans_) % scan_buffer_size_) == write_pointers_.scan);
+
 			// Store actual line data.
 			Line &active_line = line_buffer_[size_t(write_pointers_.line)];
 			active_line.end_points[1].x = location.x;
@@ -296,8 +302,8 @@ BufferingScanTarget::OutputArea BufferingScanTarget::get_output_area() {
 	area.start.line = read_ahead_pointers.line;
 	area.end.line = submit_pointers.line;
 
-	area.start.scan = read_ahead_pointers.scan_buffer;
+	area.start.scan = read_ahead_pointers.scan;
-	area.end.scan = submit_pointers.scan_buffer;
+	area.end.scan = submit_pointers.scan;
 
 	area.start.write_area_x = TextureAddressGetX(read_ahead_pointers.write_area);
 	area.start.write_area_y = TextureAddressGetY(read_ahead_pointers.write_area);
@@ -313,7 +319,7 @@ BufferingScanTarget::OutputArea BufferingScanTarget::get_output_area() {
 void BufferingScanTarget::complete_output_area(const OutputArea &area) {
 	PointerSet new_read_pointers;
 	new_read_pointers.line = uint16_t(area.end.line);
-	new_read_pointers.scan_buffer = uint16_t(area.end.scan);
+	new_read_pointers.scan = uint16_t(area.end.scan);
 	new_read_pointers.write_area = TextureAddress(area.end.write_area_x, area.end.write_area_y);
 	read_pointers_.store(new_read_pointers, std::memory_order::memory_order_relaxed);
 }

Outputs/ScanTargets/BufferingScanTarget.hpp

@@ -70,12 +70,12 @@ class BufferingScanTarget: public Outputs::Display::ScanTarget {
 		struct Line {
 			struct EndPoint {
 				uint16_t x, y;
-				uint16_t cycles_since_end_of_horizontal_retrace;
 				int16_t composite_angle;
+				uint16_t cycles_since_end_of_horizontal_retrace;
 			} end_points[2];
 
-			uint16_t line;
 			uint8_t composite_amplitude;
+			uint16_t line;
 		};
 
 		/// Provides additional metadata about lines; this is separate because it's unlikely to be of
@@ -88,6 +88,8 @@ class BufferingScanTarget: public Outputs::Display::ScanTarget {
 			/// from a frame if performance problems mean that the emulated machine is running
 			/// more quickly than complete frames can be generated.
 			bool previous_frame_was_complete;
+			/// The index of the first scan that will appear on this line.
+			size_t first_scan;
 		};
 
 		/// Sets the area of memory to use as a scan buffer.
@@ -205,7 +207,7 @@ class BufferingScanTarget: public Outputs::Display::ScanTarget {
 			int32_t write_area = 1;
 
 			// Points into the scan buffer.
-			uint16_t scan_buffer = 0;
+			uint16_t scan = 0;
 
 			// Points into the line buffer.
 			uint16_t line = 0;