Added flag checkTextureAlpha

README.md

@@ -48,6 +48,7 @@ Using obj2gltf as a command-line tool:
 |`--cesium`|Optimize the glTF for Cesium by using the sun as a default light source.|No, default `false`|
 |`--ao`|Apply ambient occlusion to the converted model.|No, default `false`|
 |`--bypassPipeline`|Bypass the gltf-pipeline for debugging purposes. This option overrides many of the options above and will save the glTF with the KHR_materials_common extension.|No, default `false`|
+|`--checkTextureAlpha`|Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel. By default textures with an alpha channel are considered to be transparent.|No, default `false`|
 
 ## Build Instructions
 

bin/obj2gltf.js

@@ -79,6 +79,11 @@ var argv = yargs
             describe: 'Bypass the gltf-pipeline for debugging purposes. This option overrides many of the options above and will save the glTF with the KHR_materials_common extension.',
             type: 'boolean',
             default: false
+        },
+        'checkTextureAlpha': {
+            describe: 'Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel. By default textures with an alpha channel are considered to be transparent.',
+            type: 'boolean',
+            default: false
         }
     }).parse(args);
 
@@ -105,7 +110,8 @@ var options = {
     generateNormals : argv.n,
     ao : argv.ao,
     optimizeForCesium : argv.cesium,
-    bypassPipeline : argv.bypassPipeline
+    bypassPipeline : argv.bypassPipeline,
+    checkTextureAlpha : argv.checkTextureAlpha
 };
 
 console.time('Total');

lib/convert.js

@@ -32,6 +32,7 @@ module.exports = convert;
  * @param {Boolean} [options.ao=false] Apply ambient occlusion to the converted model.
  * @param {Boolean} [options.textureCompressionOptions] Options sent to the compressTextures stage of gltf-pipeline.
  * @param {Boolean} [options.bypassPipeline=false] Bypass the gltf-pipeline for debugging purposes. This option overrides many of the options above and will save the glTF with the KHR_materials_common extension.
+ * @param {Boolean} [options.checkTextureAlpha=false] Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
  */
 
 function convert(objPath, gltfPath, options) {
@@ -81,7 +82,7 @@ function convert(objPath, gltfPath, options) {
         textureCompressionOptions : textureCompressionOptions
     };
 
-    return loadObj(objPath)
+    return loadObj(objPath, options)
         .then(function(objData) {
             return createGltf(objData);
         })

lib/image.js

@@ -7,6 +7,7 @@ var Promise = require('bluebird');
 
 var fsReadFile = Promise.promisify(fs.readFile);
 
+var defaultValue = Cesium.defaultValue;
 var WebGLConstants = Cesium.WebGLConstants;
 
 module.exports = loadImage;
@@ -15,11 +16,16 @@ module.exports = loadImage;
  * Load an image file and get information about it.
  *
  * @param {String} imagePath Path to the image file.
+ * @param {Object} [options] An object with the following properties:
+ * @param {Boolean} [options.checkTextureAlpha=false] Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
  * @returns {Promise} A promise resolving to the image information, or undefined if the file doesn't exist.
  *
  * @private
  */
-function loadImage(imagePath) {
+function loadImage(imagePath, options) {
+    options = defaultValue(options, defaultValue.EMPTY_OBJECT);
+    var checkTextureAlpha = defaultValue(options.checkTextureAlpha, false);
+
     return fsReadFile(imagePath)
         .then(function(data) {
             var extension = path.extname(imagePath);
@@ -38,8 +44,11 @@ function loadImage(imagePath) {
                 info.format = getFormat(channels);
 
                 if (channels === 4) {
-                    // Need to do a finer grained check over the pixels to see if the image is actually transparent
+                    if (checkTextureAlpha) {
                         info.transparent = isTransparent(data);
+                    } else {
+                        info.transparent = true;
+                    }
                 }
             }
 

lib/obj.js

@@ -51,12 +51,14 @@ var facePattern4 = /f( +(-?\d+)\/\/(-?\d+))( +(-?\d+)\/\/(-?\d+))( +(-?\d+)\/\/(
  * Parse an obj file.
  *
  * @param {String} objPath Path to the obj file.
+ * @param {Object} [options] An object with the following properties:
+ * @param {Boolean} [options.checkTextureAlpha=false] Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
  * @returns {Promise} A promise resolving to the obj data.
  * @exception {RuntimeError} The file does not have any geometry information in it.
  *
  * @private
  */
-function loadObj(objPath) {
+function loadObj(objPath, options) {
     // Global store of vertex attributes listed in the obj file
     var positions = new ArrayStorage(ComponentDatatype.FLOAT);
     var normals = new ArrayStorage(ComponentDatatype.FLOAT);
@@ -273,11 +275,11 @@ function loadObj(objPath) {
             uvs = undefined;
 
             // Load materials and images
-            return finishLoading(nodes, mtlPaths, objPath);
+            return finishLoading(nodes, mtlPaths, objPath, options);
         });
 }
 
-function finishLoading(nodes, mtlPaths, objPath) {
+function finishLoading(nodes, mtlPaths, objPath, options) {
     nodes = cleanNodes(nodes);
     if (nodes.length === 0) {
         throw new RuntimeError(objPath + ' does not have any geometry data');
@@ -285,7 +287,7 @@ function finishLoading(nodes, mtlPaths, objPath) {
     return loadMaterials(mtlPaths, objPath)
         .then(function(materials) {
             var imagePaths = getImagePaths(materials);
-            return loadImages(imagePaths, objPath)
+            return loadImages(imagePaths, options)
                 .then(function(images) {
                     return {
                         nodes : nodes,
@@ -316,10 +318,10 @@ function loadMaterials(mtlPaths, objPath) {
     });
 }
 
-function loadImages(imagePaths) {
+function loadImages(imagePaths, options) {
     var images = {};
     return Promise.map(imagePaths, function(imagePath) {
-        return loadImage(imagePath)
+        return loadImage(imagePath, options)
             .then(function(image) {
                 if (defined(image)) {
                     images[imagePath] = image;

specs/lib/imageSpec.js

@@ -77,11 +77,18 @@ describe('image', function() {
 
     it('loads image with fully opaque alpha channel', function(done) {
         expect(loadImage(opaqueAlphaImage)
+            .then(function(info) {
+                expect(info.transparent).toBe(true);
+            }), done).toResolve();
+    });
+
+    it('loads image with fully opaque alpha channel with checkTextureAlpha flag', function(done) {
+        var options = {
+            checkTextureAlpha : true
+        };
+        expect(loadImage(opaqueAlphaImage, options)
             .then(function(info) {
                 expect(info.transparent).toBe(false);
-                expect(info.format).toBe(WebGLConstants.RGBA);
-                expect(info.source).toBeDefined();
-                expect(info.extension).toBe('.png');
             }), done).toResolve();
     });