Support reading palette arrays as well as palette images (#9)

* SpriteManifest::Format: support palette images as well as palette arrays

* Read palette arrays from JSON manifest files

Michael Steenbeek <1478678+Gymnasiast@users.noreply.github.com>

Author: AaronVanGeffen

tools/gxc/src/SpriteManifest.cpp

@@ -31,15 +31,17 @@ struct Range
     }
 };
 
-static SpriteManifest::Format parseFormat(const nlohmann::json& jFormat)
+static SpriteManifest::Format parseFormat(const nlohmann::json& jFormat, const bool hasImageFile)
 {
     auto value = jFormat.get<std::string>();
     if (value == "bmp" || value == "raw")
         return SpriteManifest::Format::bmp;
     else if (value == "rle")
         return SpriteManifest::Format::rle;
+    else if (value == "palette" && hasImageFile)
+        return SpriteManifest::Format::paletteImage;
     else if (value == "palette")
-        return SpriteManifest::Format::palette;
+        return SpriteManifest::Format::paletteArray;
     else
         throw std::runtime_error("Unknown format");
 }
@@ -115,6 +117,43 @@ static std::optional<Range> parseRange(std::string_view s)
     return std::nullopt;
 }
 
+static BGRColour parseJSONPaletteColour(const std::string& s)
+{
+    uint8_t r = 0;
+    uint8_t g = 0;
+    uint8_t b = 0;
+    if (s[0] == '#' && s.size() == 7)
+    {
+        // Expect #RRGGBB
+        r = std::stoul(s.substr(1, 2), nullptr, 16) & 0xFF;
+        g = std::stoul(s.substr(3, 2), nullptr, 16) & 0xFF;
+        b = std::stoul(s.substr(5, 2), nullptr, 16) & 0xFF;
+    }
+    return { b, g, r };
+}
+
+static std::vector<BGRColour> parseColours(const nlohmann::json& jPalette)
+{
+    if (!jPalette.is_object())
+        throw std::runtime_error("parseColours expects parameter jPalette to be an object");
+
+    auto jColours = jPalette["colours"];
+    std::vector<BGRColour> out;
+
+    auto numColours = jColours.size();
+    out.reserve(numColours * 3);
+
+    for (auto& jColour : jColours)
+    {
+        if (!jColour.is_string())
+            throw std::runtime_error("Encountered a value that is not a string!");
+
+        out.push_back(parseJSONPaletteColour(jColour.get<std::string>()));
+    }
+
+    return out;
+}
+
 static SpriteManifest::Entry parseEntry(const nlohmann::json& jEntry)
 {
     SpriteManifest::Entry result;
@@ -145,21 +184,33 @@ static SpriteManifest::Entry parseEntry(const nlohmann::json& jEntry)
     }
     else
     {
-        result.path = jEntry.at("path").get<std::string>();
+        if (jEntry.contains("path"))
+            result.path = jEntry.at("path").get<std::string>();
         if (jEntry.contains("format"))
-            result.format = parseFormat(jEntry["format"]);
+            result.format = parseFormat(jEntry["format"], result.path.empty());
+
         if (jEntry.contains("palette"))
             result.palette = parsePalette(jEntry["palette"]);
+        if (jEntry.contains("colours"))
+            result.colours = parseColours(jEntry);
+
+        if (result.format == SpriteManifest::Format::automatic && !result.colours.empty())
+            result.format = SpriteManifest::Format::paletteArray;
+
         if (jEntry.contains("x"))
             result.offsetX = jEntry["x"];
         else if (jEntry.contains("x_offset"))
             result.offsetX = jEntry["x_offset"];
+        else if (jEntry.contains("index"))    // palette startIndex
+            result.offsetX = jEntry["index"]; // palette startIndex
+
         if (jEntry.contains("y"))
             result.offsetY = jEntry["y"];
         else if (jEntry.contains("y_offset"))
             result.offsetY = jEntry["y_offset"];
         else if (jEntry.contains("zoom"))
             result.zoomOffset = jEntry["zoom"];
+
         if (jEntry.contains("srcX"))
             result.srcX = jEntry["srcX"];
         if (jEntry.contains("srcY"))

tools/gxc/src/SpriteManifest.h

@@ -7,6 +7,15 @@
 
 namespace gxc
 {
+    struct BGRColour
+    {
+        uint8_t blue{};
+        uint8_t green{};
+        uint8_t red{};
+    };
+
+    using ColourVector = std::vector<BGRColour>;
+
     class SpriteArchive;
 
     class SpriteManifest
@@ -17,7 +26,8 @@ namespace gxc
             automatic,
             bmp,
             rle,
-            palette,
+            paletteImage,
+            paletteArray,
             empty
         };
 
@@ -32,6 +42,7 @@ namespace gxc
             fs::path path;
             Format format{};
             PaletteKind palette{};
+            ColourVector colours{};
             int32_t offsetX{};
             int32_t offsetY{};
             int32_t zoomOffset{};

tools/gxc/src/gxc.cpp

@@ -32,7 +32,7 @@ static void convertPaletteToBmp(const GxEntry& entry, void* dst)
     }
 }
 
-static void encodePalette(Stream& stream, const Image& image)
+static void encodePaletteFromImage(Stream& stream, const Image& image)
 {
     const auto* src = image.pixels.data();
     for (uint32_t x = 0; x < image.width; x++)
@@ -60,6 +60,14 @@ static void encodePalette(Stream& stream, const Image& image)
     }
 }
 
+static void encodePaletteFromArray(Stream& stream, const std::vector<BGRColour>& colours)
+{
+    for (auto& colour : colours)
+    {
+        stream.write(&colour, 3);
+    }
+}
+
 static std::string stringifyFlags(uint16_t flags)
 {
     std::string result;
@@ -136,6 +144,21 @@ int runBuild(const CommandLineOptions& options)
         }
         try
         {
+            // Palette arrays don't have an image to load, so start with those
+            if (manifestEntry.format == SpriteManifest::Format::paletteArray)
+            {
+                MemoryStream ms;
+                encodePaletteFromArray(ms, manifestEntry.colours);
+
+                SpriteArchive::Entry entry;
+                entry.width = manifestEntry.colours.size();
+                entry.height = 1;
+                entry.offsetX = manifestEntry.offsetX;
+                entry.flags = GxFlags::isPalette;
+                archive.addEntry(entry, ms.asSpan<const std::byte>());
+                continue;
+            }
+
             auto imageCacheIterator = imageCache.find(manifestEntry.path);
             if (imageCacheIterator == imageCache.end())
             {
@@ -151,10 +174,10 @@ int runBuild(const CommandLineOptions& options)
                 img = img.crop(manifestEntry.srcX, manifestEntry.srcY, manifestEntry.srcWidth, manifestEntry.srcHeight);
             }
 
-            if (manifestEntry.format == SpriteManifest::Format::palette)
+            if (manifestEntry.format == SpriteManifest::Format::paletteImage)
             {
                 MemoryStream ms;
-                encodePalette(ms, img);
+                encodePaletteFromImage(ms, img);
 
                 SpriteArchive::Entry entry;
                 entry.width = img.width;