AtlasGen: Separate pack and resolve steps

Common/Render/AtlasGen.cpp

@@ -100,12 +100,11 @@ inline bool CompareByArea(const Data& lhs, const Data& rhs) {
 	return lhs.w * lhs.h > rhs.w * rhs.h;
 }
 
-std::vector<Data> Bucket::Resolve(int image_width, Image *dest) {
+void Bucket::Pack(int image_width) {
 	// Place all the little images - whatever they are.
 	// Uses greedy fill algorithm. Slow but works surprisingly well, CPUs are fast.
 	ImageU8 masq;
 	masq.resize(image_width, 1);
-	dest->resize(image_width, 1);
 
 	// image_width is set to the square root of the total area of all images.
 	// We shouldn't need more than twice that in height (more likely much less).
@@ -120,11 +119,10 @@ std::vector<Data> Bucket::Resolve(int image_width, Image *dest) {
 		int idy = (int)data[i].h;
 		if (idx > 1 && idy > 1) {
 			assert(idx <= image_width);
-			for (int ty = 0; ty < maxHeight - 1; ty++) {  // TODO: Maybe remove this limit?
-				if (ty + idy + 1 > (int)dest->height()) {
+			for (int ty = 0; ty < maxHeight - 1; ty++) {
+				if (ty + idy + 1 > (int)masq.height()) {
 					// Every 16 lines of new space needed, grow the image.
 					masq.resize(image_width, ty + idy + 16);
-					dest->resize(image_width, ty + idy + 16);
 				}
 				// Brute force packing.
 				int sz = (int)data[i].w;
@@ -163,11 +161,16 @@ std::vector<Data> Bucket::Resolve(int image_width, Image *dest) {
 	// Sort the data back by ID.
 	std::sort(data.begin(), data.end(), CompareByID);
 
+	w = image_width;
+	h = masq.height();
+}
+
+std::vector<Data> Bucket::Resolve(Image *dest) {
+	dest->resize(w, h);
 	// Actually copy the image data in place, after doing the layout.
 	for (int i = 0; i < (int)data.size(); i++) {
 		dest->copyfrom(images[i], data[i].sx, data[i].sy, data[i].redToWhiteAlpha);
 	}
-
 	return data;
 }
 

Common/Render/AtlasGen.h

@@ -119,12 +119,17 @@ struct Data {
 struct Bucket {
 	std::vector<Image> images;
 	std::vector<Data> data;
+	int w = 0;
+	int h = 0;
+
 	void AddItem(Image &&img, const Data &dat) {
 		images.emplace_back(std::move(img));
 		data.emplace_back(dat);
 	}
 	void AddImage(Image &&img, int id);
-	std::vector<Data> Resolve(int image_width, Image *dest);
+
+	void Pack(int image_width);
+	std::vector<Data> Resolve(Image *dest);
 };
 
 AtlasImage ToAtlasImage(int id, std::string_view name, float tw, float th, const std::vector<Data> &results);

UI/UIAtlas.cpp

@@ -385,8 +385,12 @@ static bool GenerateUIAtlasImage(Atlas *atlas, float dpiScale, Image *dest, int
 	int imageWidth = RoundToNextPowerOf2((int)sqrtf(area));
 
 	Instant bucketStart = Instant::Now();
-	std::vector<Data> results = bucket.Resolve(imageWidth, dest);
-	INFO_LOG(Log::G3D, " - Bucketed %zu images in %.2f ms (final image size: %dx%d)", results.size(), bucketStart.ElapsedMs(), dest->width(), dest->height());
+	bucket.Pack(imageWidth);
+	INFO_LOG(Log::G3D, " - Packed in %.2f ms (image size: %dx%d)", bucketStart.ElapsedMs(), bucket.w, bucket.h);
+
+	Instant resolveStart = Instant::Now();
+	std::vector<Data> results = bucket.Resolve(dest);
+	INFO_LOG(Log::G3D, " - Resolved %zu images in %.2f ms (final image size: %dx%d)", results.size(), resolveStart.ElapsedMs(), dest->width(), dest->height());
 
 	_dbg_assert_(!results.empty());
 	// Fill out the atlas structure.

ext/native/tools/atlastool.cpp

@@ -652,9 +652,11 @@ int GenerateFromScript(const char *script_file, const char *atlas_name, bool hig
 	// Place the subimages onto the main texture. Also writes to png.
 	Image dest;
 	// Place things on the bitmap.
-	printf("Resolving...\n");
 
-	std::vector<Data> results = bucket.Resolve(image_width, &dest);
+	printf("Packing...\n");
+	bucket.Pack(image_width);
+	printf("Resolving...\n");
+	std::vector<Data> results = bucket.Resolve(&dest);
 	if (highcolor) {
 		printf("Writing .ZIM %ix%i RGBA8888...\n", dest.width(), dest.height());
 		dest.SaveZIM(image_name.c_str(), ZIM_RGBA8888 | ZIM_ZSTD_COMPRESSED);