From bca9d72a8cb982e29adf3f9086335b1c821a5861 Mon Sep 17 00:00:00 2001
From: LysiX <smyler02@gmail.com>
Date: Wed, 3 Apr 2024 11:13:37 -0700
Subject: [PATCH] Write hidden alpha in wii textures if version = 25

---
 .../Extensions/TextureExtensions.cs           | 32 ++++++++++++++++---
 .../IO/Serializers/HMXBitmapSerializer.cs     | 25 ++++++++++++---
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/Src/Core/Mackiloha.App/Extensions/TextureExtensions.cs b/Src/Core/Mackiloha.App/Extensions/TextureExtensions.cs
index 03ae536..8a05329 100644
--- a/Src/Core/Mackiloha.App/Extensions/TextureExtensions.cs
+++ b/Src/Core/Mackiloha.App/Extensions/TextureExtensions.cs
@@ -946,7 +946,7 @@ public static HMXBitmap BitmapFromImage(string imagePath, SystemInfo info)
 
             if (HasAlpha(rawData))
             {
-                var (rgbData, alphaData) = SplitRGBAForTPL(rawData);
+                var (rgbData, alphaData) = SplitRGBAForTPL(rawData, info);
 
                 // Encode as two DXT1 images
                 var rgbDxData = EncodeDxImage(rgbData, width, height, 0, DxEncoding.DXGI_FORMAT_BC1_UNORM);
@@ -960,6 +960,20 @@ public static HMXBitmap BitmapFromImage(string imagePath, SystemInfo info)
                 Array.Copy(rgbDxData, 0, combinedImageData, 0, rgbDxData.Length);
                 Array.Copy(alphaDxData, 0, combinedImageData, rgbDxData.Length, alphaDxData.Length);
 
+                if (info.Version == 25)
+                {
+                    return new HMXBitmap()
+                    {
+                        Bpp = 4,
+                        Encoding = TPL_CMP,
+                        MipMaps = 0,
+                        Width = width,
+                        Height = height,
+                        BPL = (width * 4) / 8,
+                        WiiAlphaNumber = 4,
+                        RawData = combinedImageData
+                    };
+                }
                 return new HMXBitmap()
                 {
                     Bpp = 8,
@@ -1160,7 +1174,7 @@ private static bool HasAlpha(byte[] rgbaData)
         return false;
     }
 
-    private static (byte[] rgb, byte[] alpha) SplitRGBAForTPL(byte[] data)
+    private static (byte[] rgb, byte[] alpha) SplitRGBAForTPL(byte[] data, SystemInfo info)
     {
         var rgb = new byte[data.Length];
         var alpha = new byte[data.Length];
@@ -1172,8 +1186,18 @@ private static (byte[] rgb, byte[] alpha) SplitRGBAForTPL(byte[] data)
             rgb[i + 2] = data[i + 2];
             rgb[i + 3] = 0xFF;
 
-            // Put alpha on green channel
-            alpha[i + 1] = data[i + 3];
+            if (info.Version == 25)
+            {
+                // Put alpha on all channels
+                alpha[i] = data[i + 3];
+                alpha[i + 1] = data[i + 3];
+                alpha[i + 2] = data[i + 3];
+            }
+            else
+            {
+                // Put alpha on green channel
+                alpha[i + 1] = data[i + 3];
+            }
         }
 
         return (rgb, alpha);
diff --git a/Src/Core/Mackiloha/IO/Serializers/HMXBitmapSerializer.cs b/Src/Core/Mackiloha/IO/Serializers/HMXBitmapSerializer.cs
index cc26eb5..dd1c2be 100644
--- a/Src/Core/Mackiloha/IO/Serializers/HMXBitmapSerializer.cs
+++ b/Src/Core/Mackiloha/IO/Serializers/HMXBitmapSerializer.cs
@@ -30,7 +30,10 @@ public override void WriteToStream(AwesomeWriter aw, ISerializable data)
     {
         var bitmap = data as HMXBitmap;
 
-        aw.Write((byte)0x01);
+        if (bitmap.WiiAlphaNumber == 4)
+            aw.Write((byte)0x02);
+        else
+            aw.Write((byte)0x01);
 
         aw.Write((byte)bitmap.Bpp);
         aw.Write((int)bitmap.Encoding);
@@ -40,11 +43,23 @@ public override void WriteToStream(AwesomeWriter aw, ISerializable data)
         aw.Write((short)bitmap.Height);
         aw.Write((short)bitmap.BPL);
 
-        aw.Write(new byte[19]);
+        aw.Write((short)bitmap.WiiAlphaNumber);
 
-        byte[] bytes = new byte[CalculateTextureByteSize(bitmap.Encoding, bitmap.Width, bitmap.Height, bitmap.Bpp, bitmap.MipMaps)];
-        Array.Copy(bitmap.RawData, bytes, bytes.Length);
-        aw.Write(bytes);
+        aw.Write(new byte[17]);
+
+        if (bitmap.WiiAlphaNumber == 4)
+        {
+            byte[] bytes = new byte[CalculateTextureByteSize(bitmap.Encoding, bitmap.Width, bitmap.Height, 8, bitmap.MipMaps)];
+            Array.Copy(bitmap.RawData, bytes, bytes.Length);
+            aw.Write(bytes);
+        }
+        else
+        {
+            byte[] bytes = new byte[CalculateTextureByteSize(bitmap.Encoding, bitmap.Width, bitmap.Height, bitmap.Bpp, bitmap.MipMaps)];
+            Array.Copy(bitmap.RawData, bytes, bytes.Length);
+            aw.Write(bytes);
+        }
+        
     }
 
     private int CalculateTextureByteSize(int encoding, int w, int h, int bpp, int mips, int wiiAlphaNum = 0)