Fix some texture handling.

Penumbra/Import/Textures/CombinedTexture.cs

@@ -91,7 +91,7 @@ public partial class CombinedTexture : IDisposable
 
             var tex = type switch
             {
-                TextureSaveType.AsIs   => _current.Type is Texture.FileType.Bitmap or Texture.FileType.Png ? CreateUncompressed(s, mipMaps  ) : s,
+                TextureSaveType.AsIs => _current.Type is Texture.FileType.Bitmap or Texture.FileType.Png ? CreateUncompressed( s, mipMaps ) : s,
                 TextureSaveType.Bitmap => CreateUncompressed( s, mipMaps ),
                 TextureSaveType.BC5 => CreateCompressed( s, mipMaps, false ),
                 TextureSaveType.BC7 => CreateCompressed( s, mipMaps, true ),
@@ -117,25 +117,29 @@ public partial class CombinedTexture : IDisposable
 
     private static void SaveTex( string path, ScratchImage input )
     {
-        var header = input.Meta.ToTexHeader();
+        var header = input.ToTexHeader();
         if( header.Format == TexFile.TextureFormat.Unknown )
         {
             throw new Exception( $"Could not save tex file with format {input.Meta.Format}, not convertible to a valid .tex formats." );
         }
 
-        using var stream = File.OpenWrite( path );
+        using var stream = File.Open( path, File.Exists(path) ? FileMode.Truncate : FileMode.CreateNew);
         using var w      = new BinaryWriter( stream );
         header.Write( w );
         w.Write( input.Pixels );
     }
 
     private static ScratchImage AddMipMaps( ScratchImage input, bool mipMaps )
-        => mipMaps ? input.GenerateMipMaps() : input;
+        => mipMaps
+            ? input.GenerateMipMaps( Math.Min( 13, 1 + BitOperations.Log2( ( uint )Math.Max( input.Meta.Width, input.Meta.Height ) ) ) )
+            : input;
 
     private static ScratchImage CreateUncompressed( ScratchImage input, bool mipMaps )
     {
-        if( input.Meta.Format == DXGIFormat.B8G8R8A8UNorm)
+        if( input.Meta.Format == DXGIFormat.B8G8R8A8UNorm )
-            return AddMipMaps(input, mipMaps);
+        {
+            return AddMipMaps( input, mipMaps );
+        }
 
         if( input.Meta.Format.IsCompressed() )
         {
@@ -151,8 +155,8 @@ public partial class CombinedTexture : IDisposable
 
     private static ScratchImage CreateCompressed( ScratchImage input, bool mipMaps, bool bc7 )
     {
-        var format = bc7 ? DXGIFormat.BC7UNorm : DXGIFormat.BC5UNorm;
+        var format = bc7 ? DXGIFormat.BC7UNorm : DXGIFormat.BC3UNorm;
-        if( input.Meta.Format == format)
+        if( input.Meta.Format == format )
         {
             return input;
         }

Penumbra/Import/Textures/TexFileParser.cs

@@ -61,8 +61,8 @@ public static class TexFileParser
                 return i;
             }
 
-            width      = Math.Max( width  / 2, 4 );
+            width      = Math.Max( width  / 2, 1 );
-            height     = Math.Max( height / 2, 4 );
+            height     = Math.Max( height / 2, 1 );
             lastOffset = offset;
             lastSize   = requiredSize;
         }
@@ -103,8 +103,9 @@ public static class TexFileParser
         }
     }
 
-    public static TexFile.TexHeader ToTexHeader( this TexMeta meta )
+    public static TexFile.TexHeader ToTexHeader( this ScratchImage scratch )
     {
+        var meta = scratch.Meta;
         var ret = new TexFile.TexHeader()
         {
             Height    = ( ushort )meta.Height,
@@ -121,34 +122,33 @@ public static class TexFileParser
                 _                     => 0,
             },
         };
-        unsafe
-        {
-            ret.LodOffset[ 0 ] = 0;
-            ret.LodOffset[ 1 ] = 1;
-            ret.LodOffset[ 2 ] = 2;
 
-            ret.OffsetToSurface[ 0 ] = 80;
+        ret.FillSurfaceOffsets( scratch );
-            var size = meta.Format.BitsPerPixel() * meta.Width * meta.Height / 8;
-            for( var i = 1; i < meta.MipLevels; ++i )
-            {
-                ret.OffsetToSurface[ i ] =   ( uint )( 80 + size );
-                size                     >>= 2;
-                if( size == 0 )
-                {
-                    ret.MipLevels = ( ushort )i;
-                    break;
-                }
-            }
-
-            for( var i = ret.MipLevels; i < 13; ++i )
-            {
-                ret.OffsetToSurface[ i ] = 0;
-            }
-        }
 
         return ret;
     }
 
+    private static unsafe void FillSurfaceOffsets( this ref TexFile.TexHeader header, ScratchImage scratch )
+    {
+        var idx = 0;
+        fixed( byte* ptr = scratch.Pixels )
+        {
+            foreach( var image in scratch.Images )
+            {
+                var offset = ( byte* )image.Pixels             - ptr;
+                header.OffsetToSurface[ idx++ ] = ( uint )( 80 + offset );
+            }
+        }
+
+        for( ; idx < 13; ++idx )
+            header.OffsetToSurface[ idx ] = 0;
+
+        header.LodOffset[ 0 ] = 0;
+        header.LodOffset[ 1 ] = 1;
+        header.LodOffset[ 2 ] = 2;
+    }
+
+
     public static TexMeta ToTexMeta( this TexFile.TexHeader header )
         => new()
         {