gltfpack: Display per-class image stats when -vv is set

We now display stats for embedded images that classify images by class.
Note that to do this we store the kind in BufferView::variant which is a
bit of a hack, but it works for now - we can rework this later if need
be.

gltf/gltfpack.cpp

@@ -157,6 +157,29 @@ static void printAttributeStats(const std::vector<BufferView>& views, BufferView
 	}
 }
 
+static void printImageStats(const std::vector<BufferView>& views, TextureKind kind, const char* name)
+{
+	size_t bytes = 0;
+	size_t count = 0;
+
+	for (size_t i = 0; i < views.size(); ++i)
+	{
+		const BufferView& view = views[i];
+
+		if (view.kind != BufferView::Kind_Image)
+			continue;
+
+		if (view.variant != -1 - kind)
+			continue;
+
+		count += 1;
+		bytes += view.data.size();
+	}
+
+	if (count)
+		printf("stats: image %s: %d bytes in %d images\n", name, int(bytes), int(count));
+}
+
 static bool printReport(const char* path, cgltf_data* data, const std::vector<BufferView>& views, const std::vector<Mesh>& meshes, size_t node_count, size_t mesh_count, size_t material_count, size_t animation_count, size_t json_size, size_t bin_size)
 {
 	size_t bytes[BufferView::Kind_Count] = {};
@@ -804,6 +827,11 @@ static void process(cgltf_data* data, const char* input_path, const char* output
 		printAttributeStats(views, BufferView::Kind_Index, "index");
 		printAttributeStats(views, BufferView::Kind_Keyframe, "keyframe");
 		printAttributeStats(views, BufferView::Kind_Instance, "instance");
+
+		printImageStats(views, TextureKind_Generic, "generic");
+		printImageStats(views, TextureKind_Color, "color");
+		printImageStats(views, TextureKind_Normal, "normal");
+		printImageStats(views, TextureKind_Attrib, "attrib");
 	}
 
 	if (report_path)

gltf/write.cpp

@@ -758,9 +758,9 @@ static bool parseDataUri(const char* uri, std::string& mime_type, std::string& r
 	return false;
 }
 
-static void writeEmbeddedImage(std::string& json, std::vector<BufferView>& views, const char* data, size_t size, const char* mime_type)
+static void writeEmbeddedImage(std::string& json, std::vector<BufferView>& views, const char* data, size_t size, const char* mime_type, TextureKind kind)
 {
-	size_t view = getBufferView(views, BufferView::Kind_Image, StreamFormat::Filter_None, BufferView::Compression_None, 1, -1);
+	size_t view = getBufferView(views, BufferView::Kind_Image, StreamFormat::Filter_None, BufferView::Compression_None, 1, -1 - kind);
 
 	assert(views[view].data.empty());
 	views[view].data.assign(data, size);
@@ -844,7 +844,7 @@ void writeImage(std::string& json, std::vector<BufferView>& views, const cgltf_i
 				if (!settings.texture_toktx)
 					encoded = basisToKtx(encoded, info.srgb, settings.texture_uastc);
 
-				writeEmbeddedImage(json, views, encoded.c_str(), encoded.size(), "image/ktx2");
+				writeEmbeddedImage(json, views, encoded.c_str(), encoded.size(), "image/ktx2", info.kind);
 			}
 			else
 			{
@@ -853,7 +853,7 @@ void writeImage(std::string& json, std::vector<BufferView>& views, const cgltf_i
 		}
 		else
 		{
-			writeEmbeddedImage(json, views, img_data.c_str(), img_data.size(), mime_type.c_str());
+			writeEmbeddedImage(json, views, img_data.c_str(), img_data.size(), mime_type.c_str(), info.kind);
 		}
 	}
 	else if (image.uri)