Add image bytes cache

UnityGLTF/Assets/UnityGLTF/Runtime/Scripts/Cache/ExportCache.cs

@@ -0,0 +1,53 @@
+using System.IO;
+using UnityEditor;
+using UnityEngine;
+
+namespace UnityGLTF.Cache
+{
+	internal static class ExportCache
+	{
+		private static string CacheDirectory
+		{
+			get
+			{
+				var tempDirectory = Path.Combine(Application.temporaryCachePath, "UnityGLTF");
+				return tempDirectory;
+			}
+		}
+
+		public static void Clear()
+		{
+			var dir = CacheDirectory;
+			if (Directory.Exists(dir))
+			{
+				Directory.Delete(dir, true);
+			}
+		}
+
+		public static bool TryGetBytes(Object asset, string seed, out byte[] bytes)
+		{
+#if UNITY_EDITOR
+			var path = CacheDirectory + "/" + GlobalObjectId.GetGlobalObjectIdSlow(asset) + seed;
+			if (File.Exists(path))
+			{
+				bytes = File.ReadAllBytes(path);
+				return true;
+			}
+#endif
+
+			bytes = null;
+			return false;
+		}
+
+		public static void AddBytes(Object asset, string seed, byte[] bytes)
+		{
+#if UNITY_EDITOR
+			var dir = CacheDirectory;
+			Directory.CreateDirectory(dir);
+			var path = dir + "/" + GlobalObjectId.GetGlobalObjectIdSlow(asset) + seed;
+			Debug.Log("Writing to cache: " + path);
+			File.WriteAllBytes(path, bytes);
+#endif
+		}
+	}
+}

UnityGLTF/Assets/UnityGLTF/Runtime/Scripts/SceneExporter/ExporterTextures.cs

@@ -4,6 +4,7 @@
 using GLTF.Schema;
 using UnityEngine;
 using UnityEngine.Experimental.Rendering;
+using UnityGLTF.Cache;
 using UnityGLTF.Extensions;
 using Object = UnityEngine.Object;
 using WrapMode = GLTF.Schema.WrapMode;
@@ -138,7 +139,6 @@ private void WriteRenderTextureToDiskAndRelease(RenderTexture destRenderTexture,
 				Object.Destroy(exportTexture);
 		}
 
-
 		public TextureInfo ExportTextureInfo(Texture texture, string textureSlot, TextureExportSettings exportSettings = default)
 		{
 			var info = new TextureInfo();
@@ -591,7 +591,7 @@ private ImageId ExportImageInternalBuffer(UniqueTexture uniqueTexture, string te
 				exportTexture.Apply();
 
 				var canExportAsJpeg = !textureHasAlpha && settings.UseTextureFileTypeHeuristic;
-				var imageData = canExportAsJpeg ? exportTexture.EncodeToJPG(settings.DefaultJpegQuality) : exportTexture.EncodeToPNG();
+				var imageData = GetImageData(exportTexture, canExportAsJpeg);
 				image.MimeType = canExportAsJpeg ? JPEGMimeType : PNGMimeType;
 				_bufferWriter.Write(imageData);
 
@@ -632,6 +632,16 @@ private ImageId ExportImageInternalBuffer(UniqueTexture uniqueTexture, string te
 		    return id;
 		}
 
+		private byte[] GetImageData(Texture2D texture, bool exportAsJpg)
+		{
+			var seed = texture.imageContentsHash.ToString();
+			if(ExportCache.TryGetBytes(texture, seed, out var bytes))
+				return bytes;
+			bytes = exportAsJpg ? texture.EncodeToJPG(settings.DefaultJpegQuality) : texture.EncodeToPNG();
+			ExportCache.AddBytes(texture, seed, bytes);
+			return bytes;
+		}
+
 		private SamplerId ExportSampler(Texture texture)
 		{
 			var samplerId = GetSamplerId(_root, texture);