Merge pull request #480 from KhronosGroup/fix/mimetype

Fix loading of images with undefined mimetype [473]

source/gltf/image.js

@@ -1,5 +1,6 @@
 import { GltfObject } from './gltf_object.js';
 import { isPowerOf2 } from './math_utils.js';
+import { getExtension } from './utils.js';
 import { AsyncFileReader } from '../ResourceLoader/async_file_reader.js';
 import { GL } from "../Renderer/webgl";
 import { ImageMimeType } from "./image_mime_type.js";
@@ -14,7 +15,7 @@ class gltfImage extends GltfObject
  miplevel = 0,
  bufferView = undefined,
  name = undefined,
- mimeType = ImageMimeType.JPEG,
+ mimeType = undefined,
  image = undefined)
  {
  super();
@@ -73,12 +74,41 @@ class gltfImage extends GltfObject
  });
  }
 
+ setMimetypeFromFilename(filename)
+ {
+
+ let extension = getExtension(filename)
+ if(extension == "ktx2" || extension == "ktx")
+ {
+ this.mimeType = ImageMimeType.KTX2;
+ } 
+ else if(extension == "jpg" || extension == "jpeg")
+ {
+ this.mimeType = ImageMimeType.JPEG;
+ }
+ else if(extension == "png" )
+ {
+ this.mimeType = ImageMimeType.PNG;
+ } 
+ else 
+ {
+ console.warn("MimeType not defined");
+ // assume jpeg encoding as best guess
+ this.mimeType = ImageMimeType.JPEG; 
+ }
+
+ }
+
  async setImageFromUri(gltf)
  {
  if (this.uri === undefined)
  {
  return false;
  }
+ if (this.mimeType === undefined)
+ {
+ this.setMimetypeFromFilename(this.uri);
+ }
 
  if(this.mimeType === ImageMimeType.KTX2)
  {
@@ -181,6 +211,12 @@ class gltfImage extends GltfObject
  return false;
  }
 
+ if (this.mimeType === undefined)
+ {
+ this.setMimetypeFromFilename(foundFile.name);
+ }
+
+
  if(this.mimeType === ImageMimeType.KTX2)
  {
  if (gltf.ktxDecoder !== undefined)