From b58a474a0d32bcb737b77ee61584b0ab755391b8 Mon Sep 17 00:00:00 2001
From: vnoves <vnoves@e-verse.com>
Date: Wed, 12 Nov 2025 11:33:47 -0300
Subject: [PATCH] Fix Image Gamma Unsupported By glTF

---
 .../Materials/BitmapsUtils.cs                 | 22 +++++++++++++++++++
 .../Utils/GLTFBinaryDataUtils.cs              |  6 ++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/Common_glTF_Exporter/Materials/BitmapsUtils.cs b/Common_glTF_Exporter/Materials/BitmapsUtils.cs
index b470f64..1d6f8ec 100644
--- a/Common_glTF_Exporter/Materials/BitmapsUtils.cs
+++ b/Common_glTF_Exporter/Materials/BitmapsUtils.cs
@@ -30,6 +30,28 @@ public static (string, ImageFormat) GetMimeType(string path)
             }
         }
 
+        /// <summary>
+        /// Removes non-default gamma or ICC profile metadata from a PNG/JPG file
+        /// by re-encoding it to a clean sRGB version in memory.
+        /// </summary>
+        /// <param name="path">Path to the source image</param>
+        /// <returns>Byte array of the cleaned image (PNG)</returns>
+        public static byte[] CleanGamma(string path, ImageFormat imageFormat)
+        {
+            using (var original = new Bitmap(path))
+            using (var ms = new MemoryStream())
+            {
+                // Convert to standard sRGB (System.Drawing assumes sRGB by default)
+                using (var converted = new Bitmap(original.Width, original.Height, PixelFormat.Format24bppRgb))
+                using (var g = Graphics.FromImage(converted))
+                {
+                    g.DrawImage(original, 0, 0, original.Width, original.Height);
+                    converted.Save(ms, imageFormat);
+                }
+                return ms.ToArray();
+            }
+        }
+
         public static byte[] BlendImageWithColor(
             byte[] imageBytes,
             double fade,
diff --git a/Common_glTF_Exporter/Utils/GLTFBinaryDataUtils.cs b/Common_glTF_Exporter/Utils/GLTFBinaryDataUtils.cs
index 0039ad4..93bab77 100644
--- a/Common_glTF_Exporter/Utils/GLTFBinaryDataUtils.cs
+++ b/Common_glTF_Exporter/Utils/GLTFBinaryDataUtils.cs
@@ -211,9 +211,9 @@ public static int ExportImageBuffer(
 
             if (material.pbrMetallicRoughness.baseColorTexture.index == -1)
             {
-                byte[] imageBytes = File.ReadAllBytes(material.EmbeddedTexturePath);
-                (string , ImageFormat) mimeType = BitmapsUtils.GetMimeType(material.EmbeddedTexturePath);
-
+                (string, ImageFormat) mimeType = BitmapsUtils.GetMimeType(material.EmbeddedTexturePath);
+                byte[] imageBytes = BitmapsUtils.CleanGamma(material.EmbeddedTexturePath, mimeType.Item2);
+               
                 byte[] blendedBytes = BitmapsUtils.BlendImageWithColor(imageBytes, material.Fadevalue, 
                     material.BaseColor, mimeType.Item2, material.TintColour);