(Legacy): GEM images.

Legacy/Legacy.csproj

@@ -138,6 +138,7 @@
     <Compile Include="Unknown\ArcAQA.cs" />
     <Compile Include="Unknown\AudioMSF.cs" />
     <Compile Include="Unknown\ImageCTF.cs" />
+    <Compile Include="Wing\ImageGEM.cs" />
     <Compile Include="Witch\ArcDAT.cs" />
     <Compile Include="Witch\ArcPCD.cs" />
     <Compile Include="Witch\ArcVBD.cs" />

Legacy/Wing/ImageGEM.cs

@@ -0,0 +1,143 @@
+//! \file       ImageGEM.cs
+//! \date       2018 Sep 04
+//! \brief      Wing image format.
+//
+// Copyright (C) 2018 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Windows.Media;
+using GameRes.Compression;
+
+// [030912][Wing] Minato Gensou ~Venice Fantastica~
+
+namespace GameRes.Formats.Wing
+{
+    internal class GemMetaData : ImageMetaData
+    {
+        public int  Method;
+        public int  Alpha;
+    }
+
+    [Export(typeof(ImageFormat))]
+    public class GemFormat : ImageFormat
+    {
+        public override string         Tag { get { return "GEM"; } }
+        public override string Description { get { return "Wing image format"; } }
+        public override uint     Signature { get { return 0; } }
+
+        public GemFormat ()
+        {
+            Signatures = new uint[] { 0x14000A, 0x32000A };
+        }
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            var header = file.ReadHeader (0x10);
+            int alpha = header.ToInt16 (2);
+            int method = header.ToInt16 (4);
+            if (method != 0x64 && method != 0xE6)
+                return null;
+            int bpp = header.ToInt16 (6);
+            if (bpp != 32)
+                return null;
+            return new GemMetaData {
+                Width = header.ToUInt16 (10),
+                Height = header.ToUInt16 (8),
+                BPP = bpp,
+                Method = method,
+                Alpha = alpha,
+            };
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            var reader = new GemReader (file, (GemMetaData)info);
+            var pixels = reader.Unpack();
+            return ImageData.Create (info, reader.Format, null, pixels, reader.Stride);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("GemFormat.Write not implemented");
+        }
+    }
+
+    internal class GemReader
+    {
+        IBinaryStream   m_input;
+        GemMetaData     m_info;
+        int             m_stride;
+        int             m_height;
+
+        public PixelFormat Format { get; private set; }
+        public int         Stride { get { return m_stride; } }
+
+        public GemReader (IBinaryStream input, GemMetaData info)
+        {
+            m_input = input;
+            m_info = info;
+            m_stride = (int)info.Width * 4;
+            m_height = (int)info.Height;
+            Format = m_info.Alpha == 50 ? PixelFormats.Bgra32 : PixelFormats.Bgr32;
+        }
+
+        public byte[] Unpack ()
+        {
+            m_input.Position = 0x10;
+            var pixels = new byte[m_stride * m_height];
+            using (var input = new LzssStream (m_input.AsStream, LzssMode.Decompress, true))
+                input.Read (pixels, 0, pixels.Length);
+            if (0x64 == m_info.Method)
+                RestoreRGB (pixels);
+            if (50 == m_info.Alpha)
+                RestoreAlpha (pixels);
+            return pixels;
+        }
+
+        void RestoreRGB (byte[] pixels)
+        {
+            for (int y = 1; y < m_height; ++y)
+            {
+                int dst = y * m_stride + 4;
+                for (int x = 4; x < m_stride; x += 4)
+                {
+                    int b = pixels[dst - 4] + pixels[dst - m_stride    ] - pixels[dst - m_stride - 4];
+                    int g = pixels[dst - 3] + pixels[dst - m_stride + 1] - pixels[dst - m_stride - 3];
+                    int r = pixels[dst - 2] + pixels[dst - m_stride + 2] - pixels[dst - m_stride - 2];
+                    pixels[dst  ] += (byte)b;
+                    pixels[dst+1] += (byte)g;
+                    pixels[dst+2] += (byte)r;
+                    dst += 4;
+                }
+            }
+        }
+
+        void RestoreAlpha (byte[] pixels)
+        {
+            for (int src = 3; src < pixels.Length; src += 4)
+            {
+                pixels[src] ^= 0xFF;
+            }
+        }
+    }
+}