Detect glTF 2.0 and change forward to match Cesium's convention.

Apps/SampleData/models/DracoCompressed/CesiumMilkTruck.gltf

@@ -17,6 +17,24 @@
  "children": [
  3,
  1
+ ],
+ "matrix": [
+ 0,
+ 0,
+ 1,
+ 0,
+ 0,
+ 1,
+ 0,
+ 0,
+ -1,
+ 0,
+ 0,
+ 0,
+ 0,
+ 0,
+ 0,
+ 1
  ]
  },
  {

Apps/Sandcastle/gallery/Physically-Based Materials.html

@@ -53,7 +53,7 @@
 viewer.scene.globe.depthTestAgainstTerrain = true;
 
 var position = new Cesium.Cartesian3(-1371108.6511167218, -5508684.080096612, 2901825.449865087);
-var heading = Cesium.Math.toRadians(90);
+var heading = Cesium.Math.toRadians(180);
 var pitch = Cesium.Math.toRadians(2);
 var roll = Cesium.Math.toRadians(-6);
 var hpr = new Cesium.HeadingPitchRoll(heading, pitch, roll);

Source/Scene/Model.js

@@ -579,6 +579,7 @@ define([
  this._ignoreCommands = defaultValue(options.ignoreCommands, false);
  this._requestType = options.requestType;
  this._upAxis = defaultValue(options.upAxis, Axis.Y);
+ this._forwardAxis = defaultValue(options.upAxis, Axis.Z);
 
  /**
  * @private
@@ -973,6 +974,25 @@ define([
  }
  },
 
+ /**
+ * Gets the model's forward axis.
+ * By default, glTF 2.0 models are z-forward according to the glTF spec, however older
+ * glTF (1.0, 0.8) models used x-forward. Note that only Axis.X and Axis.Z are supported.
+ *
+ * @memberof Model.prototype
+ *
+ * @type {Number}
+ * @default Axis.Z
+ * @readonly
+ *
+ * @private
+ */
+ forwardAxis : {
+ get : function() {
+ return this._forwardAxis;
+ }
+ },
+
  /**
  * Gets the model's triangle count.
  *
@@ -1361,6 +1381,10 @@ define([
  } else if (model._upAxis === Axis.X) {
  BoundingSphere.transformWithoutScale(boundingSphere, Axis.X_UP_TO_Z_UP, boundingSphere);
  }
+ if (model._forwardAxis === Axis.Z) {
+ // glTF 2.0 has a Z-forward convention that must be adapted here to X-forward.
+ BoundingSphere.transformWithoutScale(boundingSphere, Axis.Z_UP_TO_X_UP, boundingSphere);
+ }
  return boundingSphere;
  }
 
@@ -4303,6 +4327,10 @@ define([
  };
  frameState.brdfLutGenerator.update(frameState);
  updateVersion(this.gltf);
+ if (defined(this.gltf.asset) && defined(this.gltf.asset.extras) &&
+ this.gltf.asset.extras.gltf_pipeline_upgrade_10to20) {
+ this._forwardAxis = Axis.X;
+ }
  ModelUtility.checkSupportedExtensions(this.extensionsRequired);
  addPipelineExtras(this.gltf);
  addDefaults(this.gltf);
@@ -4437,6 +4465,10 @@ define([
  } else if (this._upAxis === Axis.X) {
  Matrix4.multiplyTransformation(computedModelMatrix, Axis.X_UP_TO_Z_UP, computedModelMatrix);
  }
+ if (this._forwardAxis === Axis.Z) {
+ // glTF 2.0 has a Z-forward convention that must be adapted here to X-forward.
+ Matrix4.multiplyTransformation(computedModelMatrix, Axis.Z_UP_TO_X_UP, computedModelMatrix);
+ }
  }
 
  // Update modelMatrix throughout the graph as needed

Source/ThirdParty/GltfPipeline/updateVersion.js

@@ -883,8 +883,12 @@ define([
  if (!defined(gltf.asset)) {
  gltf.asset = {};
  }
+ if (!defined(gltf.asset.extras)) {
+ gltf.asset.extras = {};
+ }
  var asset = gltf.asset;
  asset.version = '2.0';
+ asset.extras.gltf_pipeline_upgrade_10to20 = true;
  // material.instanceTechnique properties should be directly on the material. instanceTechnique is a gltf 0.8 property but is seen in some 1.0 models.
  updateInstanceTechniques(gltf);
  // animation.samplers now refers directly to accessors and animation.parameters should be removed

Specs/Data/Models/DracoCompression/CesiumMan/CesiumMan.gltf

@@ -18,13 +18,13 @@
  1
  ],
  "matrix": [
- 1,
  0,
  0,
+ 1,
  0,
+ 1,
  0,
  0,
- -1,
  0,
  0,
  1,

Specs/Data/Models/DracoCompression/CesiumMilkTruck/CesiumMilkTruck.gltf

@@ -17,6 +17,24 @@
  "children": [
  3,
  1
+ ],
+ "matrix": [
+ 0,
+ 0,
+ 1,
+ 0,
+ 0,
+ 1,
+ 0,
+ 0,
+ -1,
+ 0,
+ 0,
+ 0,
+ 0,
+ 0,
+ 0,
+ 1
  ]
  },
  {