Reorganization of material loading and returning buffer rather than w…

…riting file

CHANGES.md

@@ -6,6 +6,8 @@ Change Log
 * Breaking changes
     * Obj models now convert to glTF 2.0. Possible material profiles are `metallicRoughness`, `specGlossiness` (using the `KHR_materials_pbrSpecularGlossiness` extension), and `materialsCommon` (using the `KHR_materials_common` extension).
     * Removed `gltf-pipeline` dependency. The following options have been removed: `compress`, `optimize`, `generateNormals`, `optimizeForCesium`, `ao`, and `bypassPipeline`.
+    * Removed `inputUpAxis` and `outputUpAxis`. This stage will be incorporated into `gltf-pipeline` instead.
+    * `obj2gltf` no longer takes a `gltfPath` argument and saves a glTF file. Instead it returns a promise that resolves to the glTF JSON or glb buffer.
 
 ### 1.2.0 2017-07-11
 

README.md

@@ -8,22 +8,64 @@ Install [Node.js](https://nodejs.org/en/) if you don't already have it, and then
 ```
 npm install --save obj2gltf
 ```
-Using obj2gltf as a library:
+
+### Using obj2gltf as a command-line tool:
+
+`node bin/obj2gltf.js -i model.obj`
+
+`node bin/obj2gltf.js -i model.obj -o model.gltf`
+
+`node bin/obj2gltf.js -i model.obj -o model.glb`
+
+### Using obj2gltf as a library:
+
+#### Converting an obj model to gltf:
+
+```javascript
+var obj2gltf = require('obj2gltf');
+obj2gltf('model.obj')
+    .then(function(gltf) {
+        console.log(gltf.asset);
+    });
+```
+
+#### Converting an obj model to glb
+
 ```javascript
 var obj2gltf = require('obj2gltf');
 var options = {
-    separateTextures : true // Don't embed textures in the converted glTF
+    binary : true
 }
-obj2gltf('model.obj', 'model.gltf', options)
-    .then(function() {
-        console.log('Converted model');
+obj2gltf('model.obj', options)
+    .then(function(glb) {
+        console.log(glb.length);
     });
 ```
-Using obj2gltf as a command-line tool:
 
-`node bin/obj2gltf.js -i model.obj`
+## Material types
 
-`node bin/obj2gltf.js -i model.obj -o model.gltf`
+Traditionally the .mtl file format describes the Blinn-Phong shading model. Meanwhile glTF 2.0 introduces physically-based
+materials.
+
+There are three shading models supported by `obj2gltf`:
+
+* Metallic roughness PBR
+* Specular glossiness PBR (via `KHR_materials_pbrSpecularGlossiness` extension)
+* Materials common (via `KHR_materials_common` extension)
+
+If the material type is known in advance, it should be specified with either the `metallicRoughness`, `specularGlossiness`, or `materialsCommon` flag.
+
+In general, if a model is authored with traditional diffuse, specular, and shininess textures the `materialsCommon` flag should be passed in.
+The glTF will be saved with the `KHR_materials_common` extension and the Blinn-Phong shading model will be used.
+
+However if the model is created with PBR textures, either the `metallicRoughness` or `specularGlossiness` flag should be passed in.
+See the command line flags below for more information about how to specify PBR values inside the .mtl file.
+
+If none of these flags are provided, the .mtl is assumed to contain traditional Blinn-Phong materials which will be converted to metallic-roughness PBR.
+There may be some quality loss as traditional materials do not map perfectly to PBR materials.
+
+Commonly in PBR workflows the the .mtl file may not exist or its values may be outdated or incorrect.
+As a convenience the PBR textures may be supplied directly to the command line. See the options below.
 
 ## Usage
 
@@ -33,24 +75,22 @@ Using obj2gltf as a command-line tool:
 |----|-----------|--------|
 |`-h`, `--help`|Display help.|No|
 |`-i`, `--input`|Path to the obj file.| :white_check_mark: Yes|
-|`-o`, `--output`|Path of the converted glTF file.|No|
-|`-b`, `--binary`|Save as binary glTF.|No, default `false`|
-|`-s`, `--separate`|Writes out separate geometry data files, shader files, and textures instead of embedding them in the glTF file.|No, default `false`|
+|`-o`, `--output`|Path of the converted glTF or glb file.|No|
+|`-b`, `--binary`|Save as binary glTF (.glb).|No, default `false`|
+|`-s`, `--separate`|Writes out separate buffers and textures instead of embedding them in the glTF file.|No, default `false`|
 |`-t`, `--separateTextures`|Write out separate textures only.|No, default `false`|
 |`--checkTransparency`|Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel. By default textures are considered to be opaque.|No, default `false`|
-|`--secure`|Prevent the converter from reading image or mtl files outside of the input obj directory.|No, default `false`|
-|`--inputUpAxis`|Up axis of the obj. Choices are 'X', 'Y', and 'Z'.|No, default `Y`|
-|`--outputUpAxis`|Up axis of the converted glTF. Choices are 'X', 'Y', and 'Z'.|No, default `Y`|
+|`--secure`|Prevent the converter from reading texture or mtl files outside of the input obj directory.|No, default `false`|
 |`--packOcclusion`|Pack the occlusion texture in the red channel of metallic-roughness texture.|No, default `false`|
 |`--metallicRoughness`|The values in the mtl file are already metallic-roughness PBR values and no conversion step should be applied. Metallic is stored in the Ks and map_Ks slots and roughness is stored in the Ns and map_Ns slots.|No, default `false`|
 |`--specularGlossiness`|The values in the mtl file are already specular-glossiness PBR values and no conversion step should be applied. Specular is stored in the Ks and map_Ks slots and glossiness is stored in the Ns and map_Ns slots. The glTF will be saved with the `KHR_materials_pbrSpecularGlossiness` extension.|No, default `false`|
 |`--materialsCommon`|The glTF will be saved with the KHR_materials_common extension.|No, default `false`|
-|`--metallicRoughnessOcclusionTexture`|Path to the metallic-roughness-occlusion texture used by the model, where occlusion is stored in the red channel, roughness is stored in the green channel, and metallic is stored in the blue channel. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material. The model will be saved with a pbrMetallicRoughness material.
-|`--specularGlossinessTexture`|Path to the specular-glossiness texture used by the model, where specular color is stored in the red, green, and blue channels and specular glossiness is stored in the alpha channel. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material. The model will be saved with a material using the KHR_materials_pbrSpecularGlossiness extension.
-|`--occlusionTexture`|Path to the occlusion texture used by the model. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material. Ignored if metallicRoughnessOcclusionTexture is also set.
-|`--normalTexture`|Path to the normal texture used by the model. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material.
-|`--baseColorTexture`|Path to the baseColor/diffuse texture used by the model. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material.
-|`--emissiveTexture`|Path to the emissive texture used by the model. This may be used instead of setting texture paths in the .mtl file, and is intended for models that use one material.
+|`--metallicRoughnessOcclusionTexture`|Path to the metallic-roughness-occlusion texture that should override textures in the .mtl file, where occlusion is stored in the red channel, roughness is stored in the green channel, and metallic is stored in the blue channel. The model will be saved with a pbrMetallicRoughness material. This is often convenient in workflows where the .mtl does not exist or is not set up to use PBR materials. Intended for models with a single material.|No|
+|`--specularGlossinessTexture`|Path to the specular-glossiness texture that should override textures in the .mtl file, where specular color is stored in the red, green, and blue channels and specular glossiness is stored in the alpha channel. The model will be saved with a material using the KHR_materials_pbrSpecularGlossiness extension.|No|
+|`--occlusionTexture`|Path to the occlusion texture that should override textures in the .mtl file.|No|
+|`--normalTexture`|Path to the normal texture that should override textures in the .mtl file.|No|
+|`--baseColorTexture`|Path to the baseColor/diffuse texture that should override textures in the .mtl file.|No|
+|`--emissiveTexture`|Path to the emissive texture that should override textures in the .mtl file.|No|
 
 ## Build Instructions
 
@@ -86,11 +126,6 @@ npm run jsdoc
 
 The documentation will be placed in the `doc` folder.
 
-## Debugging
-
-* To debug the tests in Webstorm, open the Gulp tab, right click the `test` task, and click `Debug 'test'`.
-* To run a single test, change the test function from `it` to `fit`.
-
 ## Contributions
 
 Pull requests are appreciated.  Please use the same [Contributor License Agreement (CLA)](https://github.com/AnalyticalGraphicsInc/cesium/blob/master/CONTRIBUTING.md) used for [Cesium](http://cesiumjs.org/).