Perfect DXT5nm normalmaps output

ValveResourceFormat · Sep 20, 2018 · 6ce57f5 · 6ce57f5
1 parent e14f7c7
commit 6ce57f5
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Showing 2 changed files with 24 additions and 4 deletions.
diff --git a/ValveResourceFormat/Resource/ResourceTypes/Texture.cs b/ValveResourceFormat/Resource/ResourceTypes/Texture.cs
@@ -135,16 +135,20 @@ public SKBitmap GenerateBitmap()
 
                 case VTexFormat.DXT5:
                     var yCoCg = false;
+                    var normalize = false;
+                    var invert = false;
 
                     if (Resource.EditInfo.Structs.ContainsKey(ResourceEditInfo.REDIStruct.SpecialDependencies))
                     {
                         var specialDeps = (SpecialDependencies)Resource.EditInfo.Structs[ResourceEditInfo.REDIStruct.SpecialDependencies];
 
                         yCoCg = specialDeps.List.Any(dependancy => dependancy.CompilerIdentifier == "CompileTexture" && dependancy.String == "Texture Compiler Version Image YCoCg Conversion");
+                        normalize = specialDeps.List.Any(dependancy => dependancy.CompilerIdentifier == "CompileTexture" && dependancy.String == "Texture Compiler Version Image NormalizeNormals");
+                        invert = specialDeps.List.Any(dependancy => dependancy.CompilerIdentifier == "CompileTexture" && dependancy.String == "Texture Compiler Version LegacySource1InvertNormals");
                     }
 
                     SkipMipmaps(16);
-                    TextureDecompressors.UncompressDXT5(imageInfo, Reader, data, yCoCg, Width, Height);
+                    TextureDecompressors.UncompressDXT5(imageInfo, Reader, data, Width, Height, yCoCg, normalize, invert);
                     break;
 
                 case VTexFormat.I8:

diff --git a/ValveResourceFormat/Resource/ResourceTypes/TextureDecompressors.cs b/ValveResourceFormat/Resource/ResourceTypes/TextureDecompressors.cs
@@ -391,7 +391,7 @@ private static void DecompressBlockDXT1(int x, int y, int width, byte[] blockSto
             }
         }
 
-        public static void UncompressDXT5(SKImageInfo imageInfo, BinaryReader r, Span<byte> data, bool yCoCg, int w, int h)
+        public static void UncompressDXT5(SKImageInfo imageInfo, BinaryReader r, Span<byte> data, int w, int h, bool yCoCg, bool normalize, bool invert)
         {
             var blockCountX = (w + 3) / 4;
             var blockCountY = (h + 3) / 4;
@@ -401,12 +401,12 @@ public static void UncompressDXT5(SKImageInfo imageInfo, BinaryReader r, Span<by
                 for (var i = 0; i < blockCountX; i++)
                 {
                     var blockStorage = r.ReadBytes(16);
-                    DecompressBlockDXT5(i * 4, j * 4, imageInfo.Width, blockStorage, data, imageInfo.RowBytes, yCoCg);
+                    DecompressBlockDXT5(i * 4, j * 4, imageInfo.Width, blockStorage, data, imageInfo.RowBytes, yCoCg, normalize, invert);
                 }
             }
         }
 
-        private static void DecompressBlockDXT5(int x, int y, int width, byte[] blockStorage, Span<byte> pixels, int stride, bool yCoCg)
+        private static void DecompressBlockDXT5(int x, int y, int width, byte[] blockStorage, Span<byte> pixels, int stride, bool yCoCg, bool normalize, bool invert)
         {
             var alpha0 = blockStorage[0];
             var alpha1 = blockStorage[1];
@@ -531,6 +531,22 @@ private static void DecompressBlockDXT5(int x, int y, int width, byte[] blockSto
                         finalAlpha = 255; // TODO: yCoCg should have an alpha too?
                     }
 
+                    if (normalize)
+                    {
+                        var swizzleA = (finalAlpha * 2) - 255;     // premul A
+                        var swizzleG = (finalG * 2) - 255;         // premul G
+                        var deriveB = (int)System.Math.Sqrt((255 * 255) - (swizzleA * swizzleA) - (swizzleG * swizzleG));
+                        finalR = ClampColor((swizzleA / 2) + 128); // unpremul A and normalize (128 = forward, or facing viewer)
+                        finalG = ClampColor((swizzleG / 2) + 128); // unpremul G and normalize
+                        finalB = ClampColor((deriveB / 2) + 128);  // unpremul B and normalize
+                        finalAlpha = 255;
+                    }
+
+                    if (invert)
+                    {
+                        finalG = (byte)(~finalG);  // LegacySource1InvertNormals
+                    }
+
                     pixels[pixelIndex] = finalB;
                     pixels[pixelIndex + 1] = finalG;
                     pixels[pixelIndex + 2] = finalR;