[WzLib] WzPngProperty -- speed up the performance of decompressing bg…

…ra444 pixel data

MapleLib/WzLib/WzProperties/WzPngProperty.cs

@@ -27,6 +27,7 @@
 using MapleLib.Converters;
 using MapleLib.WzLib.Util;
 using Microsoft.Xna.Framework.Graphics;
+using Microsoft.Xna.Framework.Graphics.PackedVector;
 
 namespace MapleLib.WzLib.WzProperties
 {
@@ -556,25 +557,49 @@ public static Color RGB565ToColor(ushort val)
             return c;
         }
 
+        /// <summary>
+        /// For debugging: an example of this image may be found at "Effect.wz\\5skill.img\\character_delayed\\0"
+        /// </summary>
+        /// <param name="rawData"></param>
+        /// <param name="width"></param>
+        /// <param name="height"></param>
+        /// <param name="bmp"></param>
+        /// <param name="bmpData"></param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void DecompressImage_PixelDataBgra4444(byte[] rawData, int width, int height, Bitmap bmp, BitmapData bmpData)
+        public unsafe static void DecompressImage_PixelDataBgra4444(byte[] rawData, int width, int height, Bitmap bmp, BitmapData bmpData)
         {
             int uncompressedSize = width * height * 2;
-            byte[] decoded = new byte[uncompressedSize * 2];
 
-            for (int i = 0; i < uncompressedSize; i++)
+            // Declare an "unsafe" pointer to the raw data
+            fixed (byte* dataPointer = rawData)
             {
-                byte byteAtPosition = rawData[i];
+                // Create pointers for the B, G, and R values of each pixel
+                byte* bPointer = dataPointer;
+                byte* gPointer = dataPointer + 1;
 
-                int lo = byteAtPosition & 0x0F;
-                byte b = (byte)(lo | (lo << 4));
-                decoded[i * 2] = b;
+                // Iterate over the pixels
+                for (int i = 0; i < uncompressedSize; i += 2)
+                {
+                    // Get the B and G values of the current pixel
+                    byte b = *bPointer;
+                    byte g = *gPointer;
+
+                    // Decompress the B and G values
+                    b = (byte)((b >> 4) | (b >> 4));
+                    g = (byte)(g | (g << 4));
+
+                    // Set the decompressed B and G values for the current pixel
+                    *bPointer = b;
+                    *gPointer = g;
 
-                int hi = byteAtPosition & 0xF0;
-                byte g = (byte)(hi | (hi >> 4));
-                decoded[i * 2 + 1] = g;
+                    // Move the pointers to the next pixel
+                    bPointer += 2;
+                    gPointer += 2;
+                }
             }
-            Marshal.Copy(decoded, 0, bmpData.Scan0, decoded.Length);
+
+            // Copy the decompressed data to the bitmap
+            Marshal.Copy(rawData, 0, bmpData.Scan0, rawData.Length);
             bmp.UnlockBits(bmpData);
         }
 
@@ -844,6 +869,7 @@ internal void CompressPng(Bitmap bmp)
             format2 = 0;
             width = bmp.Width;
             height = bmp.Height;
+
             //byte[] bmpBytes = bmp.BitmapToBytes();
             /* if (SquishPNGWrapper.CheckAndLoadLibrary())
                         {