Merge

extensions/CESIUM_RTC/CESIUM_RTC.schema.json

@@ -12,7 +12,7 @@
             },
             "minItems" : 3,
             "maxItems" : 3            
-        },
+        }
     },
     "additionalProperties" : false
-}
+}

extensions/binary_glTF/README.md → extensions/EXT_binary_glTF/README.md

@@ -1,20 +1,16 @@
-# binary_glTF
+# EXT_binary_glTF
 
 ## Contributors
 
-* Patrick Cozzi, [@pjcozzi](https://twitter.com/pjcozzi)
-* Tom Fili, [@CesiumFili](https://twitter.com/CesiumFili)
-* Kai Ninomiya, [@kainino0x](https://twitter.com/kainino0x)
-* Max Limper, [@mlimper_cg](https://twitter.com/mlimper_cg)
-* Maik Thöner, [@mthoener](https://twitter.com/mthoener)
-
-## Status
-
-Draft
+* Patrick Cozzi, Cesium, [@pjcozzi](https://twitter.com/pjcozzi)
+* Tom Fili, Cesium, [@CesiumFili](https://twitter.com/CesiumFili)
+* Kai Ninomiya, Cesium, [@kainino0x](https://twitter.com/kainino0x)
+* Max Limper, Fraunhofer IGD, [@mlimper_cg](https://twitter.com/mlimper_cg)
+* Maik Thöner, Fraunhofer IGD, [@mthoener](https://twitter.com/mthoener)
 
 ## Dependencies
 
-Written against the glTF 0.8 spec.
+Written against the glTF draft 1.0 spec.
 
 ## Overview
 
@@ -23,7 +19,7 @@ glTF provides two delivery options that can be also be used together:
 * glTF JSON points to external binary data (geometry, key frames, skins), images, and shaders.
 * glTF JSON embeds base64-encoded binary data, images, and shaders inline using data URIs.
 
-glTF is commonly criticized for requiring either separate requests or extra space due to base64-encoding.  Base64-encoding requires extra processing to decode and increases the file size (by ~33% for encoded resources).  While gzip mitigates the file size increase, decompression and decoding still add significant loading time.
+For these data, glTF requires either separate requests or extra space due to base64-encoding.  Base64-encoding requires extra processing to decode and increases the file size (by ~33% for encoded resources).  While gzip mitigates the file size increase, decompression and decoding still add significant loading time.
 
 To solve this, this extension introduces a container format, _Binary glTF_.
 In Binary glTF, glTF resources (JSON data, .bin, images, and shaders) can be stored in a binary blob accessed in JavaScript as an `ArrayBuffer`. 
@@ -36,19 +32,17 @@ This binary blob (which can be a file, for example) is always divided into three
 The scene part can then refer to external resources (as usual), but also to resources stored within the binary file body.
 Informally, this is like embedding the JSON, images, and shaders in an .bin file.
 
-
 _TODO: this is browser implementation stuff
 In a browser, the `TextDecoder` JavaScript API can be used to extract the glTF scene from the arraybuffer. 
 A scene encoded as JSON can be parsed with `JSON.parse` as usual, and then the arraybuffer is treated as a glTF `buffer`.
 
-
 ## Binary glTF Layout
 
 Binary glTF is little endian. Figure 1 shows an overview of the three parts of a Binary glTF file.
 
 **Figure 1**: Binary glTF layout.
 
-![](layout.png)
+![](figures/layout.png)
 
 The following sections show the structure of the three different parts more in detail.
 
@@ -73,6 +67,7 @@ _TODO: should there be a more sophisticated way of specifying the version, such
 | 1       | 0x00000001 | Version 1         |                            |
 
 
+<<<<<<< HEAD:extensions/binary_glTF/README.md
 **Table 2**: Valid values for 'sceneFormat'
 | Decimal | Hex        | Short Description | Comment                    |
 |--------:|-----------:|------------------:|---------------------------:|
@@ -84,40 +79,6 @@ This way, it is also possible to read only a selected subset of resources from a
 
 The start of the binary body data is 4-byte aligned to ease its use with JavaScript Typed Arrays.
 
-Given an `arrayBuffer` with Binary glTF, Listing 1 shows how to parse the header and access the JSON.
-
-_TODO: the code below is out-of-sync with Cesium and the Frauhofer SRC implementations_
-
-**Listing 1**: Parsing Binary glTF.  This uses a `TextDecoder` wrapper in Cesium, [`getStringFromTypedArray`](https://github.com/AnalyticalGraphicsInc/cesium/blob/1.11/Source/Core/getStringFromTypedArray.js).
-```javascript
-var sizeOfUint32 = Uint32Array.BYTES_PER_ELEMENT;
-
-var magic = getStringFromTypedArray(arrayBuffer, 0, 4);
-if (magic !== 'glTF') {
-    // Not Binary glTF
-}
-
-var view = new DataView(arrayBuffer);
-var byteOffset = sizeOfUint32;  // Skip magic number
-
-var version = view.getUint32(byteOffset, true);
-byteOffset += sizeOfUint32;
-if (version !== 1) {
-    // This only handles version 1.
-}
-
-byteOffset += sizeOfUint32;  // Skip length
-
-var jsonOffset = view.getUint32(byteOffset, true);
-byteOffset += sizeOfUint32;
-
-var jsonLength = view.getUint32(byteOffset, true);
-byteOffset += sizeOfUint32;
-
-var jsonString = getStringFromTypedArray(arrayBuffer, jsonOffset, jsonLength);
-var json = JSON.parse(jsonString)
-```
-
 Strings in the Binary glTF, i.e., JSON or shaders, are UTF-8.
 
 Binary glTF still supports external resources.  For example, an application that wants to download textures on demand may embed everything except images in the Binary glTF.
@@ -128,10 +89,10 @@ Binary glTF also supported embedded base64-encoded resources, but it would be in
 
 This extension introduces an explicitly named `buffer` called `binary_glTF`.  This buffer is an implicit reference to the arraybuffer that is the Binary glTF.  It only has one property, `"type": "arraybuffer"`.  When a runtime encounters this, it should use the already loaded Binary glTF arrayBuffer as the buffer.  `bufferViews` that reference this `buffer` work as usual.
 
-To support embedded shaders and images, `shader` and `image` glTF properties have new `binary_glTF` extension properties and no longer require the `uri` property.  See Listings 2 and 3.
+To support embedded shaders and images, `shader` and `image` glTF properties have new `binary_glTF` extension properties that should be used insted of the `uri` property.  See Listings 2 and 3.
 
 **Listing 2**: A `shader` referencing a `bufferview` to access an embedded shader source.
-```json
+```javascript
 "a_shader" : {
     "extensions" : {
         "binary_glTF" : {
@@ -141,8 +102,8 @@ To support embedded shaders and images, `shader` and `image` glTF properties hav
 }
 ```
 
-**Listing 3**: An `image` referencing a `bufferview` and with metadata useful for loading the image from the arrayBuffer.  In JavaScript, `Blob` can be used as the source for an `Image` to extract an image from the arraybuffer.  See Cesium's [`loadImageFromTypedArray`](https://github.com/AnalyticalGraphicsInc/cesium/blob/bgltf/Source/Core/loadImageFromTypedArray.js) helper function.
-```json
+**Listing 3**: An `image` referencing a `bufferview` and with metadata useful for loading the image from the arrayBuffer.  In JavaScript, `Blob` can be used as the source for an `Image` to extract an image from the arraybuffer (for example, see Cesium's [`loadImageFromTypedArray`](https://github.com/AnalyticalGraphicsInc/cesium/blob/1.13/Source/Core/loadImageFromTypedArray.js) helper function).
+```javascript
 "an_image" : {
     "extensions" : {
         "binary_glTF" : {
@@ -167,9 +128,30 @@ TODO
 
 Use `model/vnd.gltf.binary`.
 
-## Experimental Results
+## Known Implementations
+
+### Runtime
+
+* Cesium ([code](https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/Model.js))
+
+### Tools
+
+* Cesium COLLADA-to-glTF Converter ([app](http://cesiumjs.org/convertmodel.html))
+* colladaToBglTFConverter ([code](https://github.com/virtualcitySYSTEMS/colladaToBglTFConverter))
+* SRC writer source code ([code](http://x3dom.org/src/files/src_writer_source.zip))
+
+## Resources
+
+* Discussion - [#357](https://github.com/KhronosGroup/glTF/issues/357) and [#400](https://github.com/KhronosGroup/glTF/pull/400)
+* base64-encoded data in glTF - [#68](https://github.com/KhronosGroup/glTF/issues/68)
+* [Faster 3D Models with Binary glTF](http://cesiumjs.org/2015/06/01/Binary-glTF/) article on CESIUM_binary_glTF the Cesium blog
+* SRC project page (paper, background, basic writer) - [http://x3dom.org/src/](http://x3dom.org/src/)
+
+## Performance Results
 
-Based on extensive experimentation (below & [[1]](#BenchData)) using Cesium's glTF loader, different configurations are recommended for different scenarios.
+_This section is non-normative._
+
+Based on experimentation (below & [[1]](#BenchData)) using CESIUM_binary_glTF and Cesium's glTF loader (only trivial differences to EXT_binary_glTF), different configurations are recommended for different scenarios.
 
 * To minimize file size and number of files, use Binary glTF (gzipped), and external compressed image files (PNG, JPEG, etc.) to avoid significant decompression overhead.
 * If a single file is desired, use Binary glTF (gzipped) with all files embedded.
@@ -206,31 +188,5 @@ Using the 1200 12th Ave model (thanks to [Cube Cities](http://cubecities.com/)),
 
 \* All files gzipped except for stand-alone images.
 
-These tests were performed with the CESIUM_binary_glTF implementation.
-With SRC [[2]](#SRCPaper), there is another, slightly different implementation of Binary glTF, but the difference of benchmark results is insignificant.
-
-
-## Known Implementations
-
-### Runtime
-
-* Cesium ([code](https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/Model.js))
-
-### Tools
-
-* Cesium COLLADA-to-glTF Converter ([app](http://cesiumjs.org/convertmodel.html))
-* colladaToBglTFConverter ([code](https://github.com/virtualcitySYSTEMS/colladaToBglTFConverter))
-* SRC writer source code ([code](http://x3dom.org/src/files/src_writer_source.zip))
-
-## Resources
-
-* Discussion - [#357](https://github.com/KhronosGroup/glTF/issues/357)
-* base64-encoded data in glTF - [#68](https://github.com/KhronosGroup/glTF/issues/68)
-* [Faster 3D Models with Binary glTF](http://cesiumjs.org/2015/06/01/Binary-glTF/) article on the Cesium blog
-* SRC project page (paper, background, basic writer) - [http://x3dom.org/src/](http://x3dom.org/src/)
-
 <a name="BenchData">
 * [1] Raw data for benchmarks using compression available in [BenchData](BenchData/README.md) supplemental.
-
-<a name="SRCPaper">
-* [2] SRC paper [http://x3dom.org/src/files/Web3d2014_SRC.pdf](http://x3dom.org/src/files/Web3d2014_SRC.pdf)

extensions/README.md

@@ -1,3 +1,8 @@
+## Multi-vendor extensions
+
+* [EXT_binary_glTF](EXT_binary_glTF/README.md)
+
+## Vendor extensions
+
 * [CESIUM_RTC](CESIUM_RTC/README.md)
 * [CESIUM_binary_glTF](CESIUM_binary_glTF/README.md)
-* [binary_glTF](binary_glTF/README.md)