shithub: rgbds

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Fix transparency handling

Ensure that the color count is properly used, and that
transparency is not counted as a color when packing palettes

--- a/include/gfx/proto_palette.hpp

+++ b/include/gfx/proto_palette.hpp

@@ -34,6 +34,7 @@

 	ComparisonResult compare(ProtoPalette const &other) const;

 	size_t size() const;

+	bool empty() const;

 	decltype(_colorIndices)::const_iterator begin() const;

 	decltype(_colorIndices)::const_iterator end() const;

--- a/src/gfx/convert.cpp

+++ b/src/gfx/convert.cpp

@@ -441,6 +441,8 @@

 	bool bank;

 	bool yFlip;

 	bool xFlip;

+

+	static constexpr decltype(protoPaletteID) transparent = SIZE_MAX;

 };

 static std::tuple<DefaultInitVec<size_t>, std::vector<Palette>>

@@ -459,6 +461,13 @@

 	}

 	std::vector<Palette> palettes(nbPalettes);

+	// If the image contains at least one transparent pixel, force transparency in the first slot of

+	// all palettes

+	if (options.hasTransparentPixels) {

+		for (Palette &pal : palettes) {

+			pal.colors[0] = Rgba::transparent;

+		}

+	}

 	// Generate the actual palettes from the mappings

 	for (size_t protoPalID = 0; protoPalID < mappings.size(); ++protoPalID) {

 		auto &pal = palettes[mappings[protoPalID]];

@@ -676,7 +685,9 @@

 	auto iter = attrmap.begin();

 	for (auto tile : png.visitAsTiles(options.columnMajor)) {

-		Palette const &palette = palettes[mappings[iter->protoPaletteID]];

+		size_t protoPaletteID = iter->protoPaletteID;

+		// If the tile is fully transparent, default to palette 0

+		Palette const &palette = palettes[protoPaletteID != AttrmapEntry::transparent ? mappings[protoPaletteID] : 0];

 		for (uint32_t y = 0; y < 8; ++y) {

 			uint16_t bitplanes = TileData::rowBitplanes(tile, palette, y);

 			output.sputc(bitplanes & 0xFF);

@@ -843,7 +854,7 @@

 	options.verbosePrint(Options::VERB_CFG, "Using libpng %s\n", png_get_libpng_ver(nullptr));

 	options.verbosePrint(Options::VERB_LOG_ACT, "Reading tiles...\n");

-	Png png(options.input);

+	Png png(options.input); // This also sets `hasTransparentPixels` as a side effect

 	ImagePalette const &colors = png.getColors();

 	// Now, we have all the image's colors in `colors`

@@ -851,13 +862,11 @@

 	if (options.verbosity >= Options::VERB_INTERM) {

 		fputs("Image colors: [ ", stderr);

-		size_t i = 0;

 		for (auto const &slot : colors) {

 			if (!slot.has_value()) {

 				continue;

 			}

-			fprintf(stderr, "#%08x%s", slot->toCSS(), i != colors.size() - 1 ? ", " : "");

-			++i;

+			fprintf(stderr, "#%08x, ", slot->toCSS());

 		}

 		fputs("]\n", stderr);

 	}

@@ -875,10 +884,19 @@

 		for (uint32_t y = 0; y < 8; ++y) {

 			for (uint32_t x = 0; x < 8; ++x) {

-				tileColors.add(tile.pixel(x, y).cgbColor());

+				Rgba color = tile.pixel(x, y);

+				if (!color.isTransparent()) { // Do not count transparency in for packing

+					tileColors.add(color.cgbColor());

+				}

 			}

 		}

+		if (tileColors.empty()) {

+			// "Empty" proto-palettes screw with the packing process, so discard those

+			attrs.protoPaletteID = AttrmapEntry::transparent;

+			continue;

+		}

+

 		// Insert the proto-palette, making sure to avoid overlaps

 		for (size_t n = 0; n < protoPalettes.size(); ++n) {

 			switch (tileColors.compare(protoPalettes[n])) {

@@ -909,6 +927,9 @@

 			}

 		}

 		attrs.protoPaletteID = protoPalettes.size();

+		if (protoPalettes.size() == AttrmapEntry::transparent) {

+			abort(); // TODO: nice error message

+		}

 		protoPalettes.push_back(tileColors);

 contained:;

 	}

@@ -915,6 +936,15 @@

 	options.verbosePrint(Options::VERB_INTERM, "Image contains %zu proto-palette%s\n",

 	                     protoPalettes.size(), protoPalettes.size() != 1 ? "s" : "");

+	if (options.verbosity >= Options::VERB_INTERM) {

+		for (auto const &protoPal : protoPalettes) {

+			fputs("[ ", stderr);

+			for (uint16_t color : protoPal) {

+				fprintf(stderr, "$%04x, ", color);

+			}

+			fputs("]\n", stderr);

+		}

+	}

 	// Sort the proto-palettes by size, which improves the packing algorithm's efficiency

 	// We sort after all insertions to avoid moving items: https://stackoverflow.com/a/2710332

--- a/src/gfx/pal_packing.cpp

+++ b/src/gfx/pal_packing.cpp

@@ -401,7 +401,7 @@

 				continue;

 			}

-			options.verbosePrint(Options::VERB_DEBUG, "%zu/%zu: Rel size: %f (size = %zu)\n", i,

+			options.verbosePrint(Options::VERB_DEBUG, "%zu/%zu: Rel size: %f (size = %zu)\n", i + 1,

 			                     assignments.size(), assignments[i].relSizeOf(protoPal),

 			                     protoPal.size());

 			if (assignments[i].relSizeOf(protoPal) < bestRelSize) {

--- a/src/gfx/proto_palette.cpp

+++ b/src/gfx/proto_palette.cpp

@@ -66,6 +66,10 @@

 	return std::distance(begin(), end());

 }

+bool ProtoPalette::empty() const {

+	return _colorIndices[0] == UINT16_MAX;

+}

+

 auto ProtoPalette::begin() const -> decltype(_colorIndices)::const_iterator {

 	return _colorIndices.begin();

 }