Merge pull request #42 from TomHarte/PaletteRotation

Fix palettisation, add manual hack for picking a good colour 0.

Author: TomHarte

preprocessor/Map Preprocessor/AppDelegate.mm

@@ -377,7 +377,8 @@ - (void)encode:(NSString *)directory {
 	NSArray<NSString *> *sprite_files = [self spriteFiles:directory];
 
 	// Build palette based on tiles and sprites.
-	Palettiser palettiser;
+	Palettiser palettiser(4);	// TODO: super-hack here; I'm supplying a rotation I picked to make sure that
+								// colour 0 is the background one. That needs to be automated.
 	for(NSString *file in [tile_files arrayByAddingObjectsFromArray:sprite_files]) {
 		NSData *fileData = [NSData dataWithContentsOfFile:file];
 		const PixelAccessor accessor([[NSImage alloc] initWithData:fileData]);

preprocessor/Map Preprocessor/Serialisers/Palettiser.h

@@ -18,6 +18,8 @@ struct Palette {
 template <size_t TargetCount = 16, size_t TargetOffset = 0>
 class Palettiser {
 public:
+	Palettiser(size_t rotation) : rotation_(rotation) {}
+
 	void add_colour(uint32_t colour) {
 		colours_.insert(colour);
 	}
@@ -60,6 +62,10 @@ class Palettiser {
 			Bucket *selected_bucket = nullptr;
 			int max_range = 0;
 			for(auto &bucket: buckets) {
+				if(bucket.colours.size() == 1) {
+					continue;
+				}
+
 				uint32_t max = 0, min = 255;
 				for(int index = 0; index < 24; index += 8) {
 					for(const auto colour: bucket.colours) {
@@ -101,10 +107,15 @@ class Palettiser {
 
 		// Build final palette.
 		Palette result;
+		result.sam_palette.resize(TargetCount);
+		uint8_t palette_index = rotation_;
 		for(const auto &bucket: buckets) {
+			const uint8_t index = palette_index + TargetOffset;
+			palette_index = (palette_index + 1) % TargetCount;
+
 			uint32_t sum[3]{};
 			for(const auto colour: bucket.colours) {
-				result.source_mapping[colour] = static_cast<uint8_t>(result.sam_palette.size());
+				result.source_mapping[colour] = index;
 				sum[0] += (colour >> 0) & 0xff;
 				sum[1] += (colour >> 8) & 0xff;
 				sum[2] += (colour >> 16) & 0xff;
@@ -137,12 +148,13 @@ class Palettiser {
 				// when there is meant to be none than it does to have the whole
 				// colour be slightly darker.
 				((bright >= 2 && red && green && blue) ? 0x01 : 0x00);
-			result.sam_palette.push_back(sam_colour);
+			result.sam_palette[index] = sam_colour;
 		}
 
 		return result;
 	}
 
 private:
 	std::unordered_set<uint32_t> colours_;
+	size_t rotation_;
 };

src/generated/palette.z80s

@@ -1,2 +1,2 @@
 	palette:
-		db 0x00, 0x20, 0x40, 0x08, 0x00, 0x28, 0x58, 0x52, 0x12, 0x7e, 0x6c, 0x64, 0x00, 0x00, 0x00, 0x00
+		db 0x5a, 0x1a, 0x63, 0x2c, 0x00, 0x20, 0x40, 0x08, 0x64, 0x24, 0x48, 0x52, 0x12, 0x7e, 0x6c, 0x0c