Add support for KHR_materials_unlit

CHANGES.md

@@ -1,6 +1,11 @@
 Change Log
 ==========
 
+### 1.50 - 2018-10-01
+
+##### Additions :tada:
+* Added support for glTF extension [KHR_materials_unlit](https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit) [#6977](https://github.com/AnalyticalGraphicsInc/cesium/pull/6977).
+
 ### 1.49 - 2018-09-04
 
 ##### Breaking Changes :mega:
@@ -15,7 +20,6 @@ Change Log
 * Added `GeocoderViewModel.destinationFound` for specifying a function that is called upon a successful geocode.  The default behavior is to fly to the destination found by the geocoder. [#6915](https://github.com/AnalyticalGraphicsInc/cesium/pull/6915
 * Added `ClippingPlaneCollection.planeAdded` and `ClippingPlaneCollection.planeRemoved` events.  `planeAdded` is raised when a new plane is added to the collection and `planeRemoved` is raised when a plane is removed. [#6875](https://github.com/AnalyticalGraphicsInc/cesium/pull/6875)
 * Added `Matrix4.setScale` for setting the scale on an affine transformation matrix [#6888](https://github.com/AnalyticalGraphicsInc/cesium/pull/6888)
-)
 * Added optional `width` and `height` to `Scene.drillPick` for specifying a search area. [#6922](https://github.com/AnalyticalGraphicsInc/cesium/pull/6922)
 * Added `Cesium3DTileset.root` for getting the root tile of a tileset. [#6944](https://github.com/AnalyticalGraphicsInc/cesium/pull/6944)
 * Added `Cesium3DTileset.extras` and `Cesium3DTile.extras` for getting application specific metadata from 3D Tiles. [#6974](https://github.com/AnalyticalGraphicsInc/cesium/pull/6974)

Source/Scene/ModelUtility.js

@@ -473,7 +473,8 @@ define([
         'KHR_draco_mesh_compression' : true,
         'KHR_materials_common' : true,
         'KHR_techniques_webgl' : true,
-        'WEB3D_quantized_attributes' : true
+        'WEB3D_quantized_attributes' : true,
+        'KHR_materials_unlit' : true
     };
 
     ModelUtility.checkSupportedExtensions = function(extensionsRequired) {

Source/Scene/processPbrMetallicRoughness.js

@@ -143,6 +143,7 @@ define([
         var hasNormals = false;
         var hasTangents = false;
         var hasTexCoords = false;
+        var isUnlit = false;
 
         if (defined(primitiveInfo)) {
             skinningInfo = primitiveInfo.skinning;
@@ -181,6 +182,12 @@ define([
             }
         };
 
+        if (defined(material.extensions) && defined(material.extensions.KHR_materials_unlit)) {
+            isUnlit = true;
+            hasNormals = false;
+            hasTangents = false;
+        }
+
         if (hasNormals) {
             techniqueUniforms.u_normalMatrix = {
                 semantic : 'MODELVIEWINVERSETRANSPOSE',
@@ -628,19 +635,21 @@ define([
             fragmentShader += '    vec3 color = baseColor;\n';
         }
 
-        if (defined(generatedMaterialValues.u_occlusionTexture)) {
-            fragmentShader += '    color *= texture2D(u_occlusionTexture, ' + v_texcoord + ').r;\n';
-        }
-        if (defined(generatedMaterialValues.u_emissiveTexture)) {
-            fragmentShader += '    vec3 emissive = SRGBtoLINEAR3(texture2D(u_emissiveTexture, ' + v_texcoord + ').rgb);\n';
-            if (defined(generatedMaterialValues.u_emissiveFactor)) {
-                fragmentShader += '    emissive *= u_emissiveFactor;\n';
+        // Ignore occlusion and emissive when unlit
+        if (!isUnlit) {
+            if (defined(generatedMaterialValues.u_occlusionTexture)) {
+                fragmentShader += '    color *= texture2D(u_occlusionTexture, ' + v_texcoord + ').r;\n';
             }
-            fragmentShader += '    color += emissive;\n';
-        }
-        else if (defined(generatedMaterialValues.u_emissiveFactor)) {
+            if (defined(generatedMaterialValues.u_emissiveTexture)) {
+                fragmentShader += '    vec3 emissive = SRGBtoLINEAR3(texture2D(u_emissiveTexture, ' + v_texcoord + ').rgb);\n';
+                if (defined(generatedMaterialValues.u_emissiveFactor)) {
+                    fragmentShader += '    emissive *= u_emissiveFactor;\n';
+                }
+                fragmentShader += '    color += emissive;\n';
+            } else if (defined(generatedMaterialValues.u_emissiveFactor)) {
                 fragmentShader += '    color += u_emissiveFactor;\n';
             }
+        }
 
         // Final color
         fragmentShader += '    color = LINEARtoSRGB(color);\n';

Specs/Data/Models/PBR/BoxUnlit/BoxUnlit.gltf

@@ -0,0 +1,151 @@
+{
+    "asset": {
+        "generator": "COLLADA2GLTF",
+        "version": "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_unlit"
+    ],
+    "extensionsRequired": [
+        "KHR_materials_unlit"
+    ],
+    "scene": 0,
+    "scenes": [
+        {
+            "nodes": [
+                0
+            ]
+        }
+    ],
+    "nodes": [
+        {
+            "children": [
+                1
+            ],
+            "matrix": [
+                1.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                -1.0,
+                0.0,
+                0.0,
+                1.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                1.0
+            ]
+        },
+        {
+            "mesh": 0
+        }
+    ],
+    "meshes": [
+        {
+            "primitives": [
+                {
+                    "attributes": {
+                        "NORMAL": 1,
+                        "POSITION": 2
+                    },
+                    "indices": 0,
+                    "mode": 4,
+                    "material": 0
+                }
+            ],
+            "name": "Mesh"
+        }
+    ],
+    "accessors": [
+        {
+            "bufferView": 0,
+            "byteOffset": 0,
+            "componentType": 5123,
+            "count": 36,
+            "max": [
+                23
+            ],
+            "min": [
+                0
+            ],
+            "type": "SCALAR"
+        },
+        {
+            "bufferView": 1,
+            "byteOffset": 0,
+            "componentType": 5126,
+            "count": 24,
+            "max": [
+                1.0,
+                1.0,
+                1.0
+            ],
+            "min": [
+                -1.0,
+                -1.0,
+                -1.0
+            ],
+            "type": "VEC3"
+        },
+        {
+            "bufferView": 1,
+            "byteOffset": 288,
+            "componentType": 5126,
+            "count": 24,
+            "max": [
+                0.5,
+                0.5,
+                0.5
+            ],
+            "min": [
+                -0.5,
+                -0.5,
+                -0.5
+            ],
+            "type": "VEC3"
+        }
+    ],
+    "materials": [
+        {
+            "pbrMetallicRoughness": {
+                "baseColorFactor": [
+                    0.0,
+                    1.0,
+                    0.0,
+                    1.0
+                ],
+                "metallicFactor": 1.0
+            },
+            "name": "Unlit Green",
+            "extensions": {
+                "KHR_materials_unlit": {}
+            }
+        }
+    ],
+    "bufferViews": [
+        {
+            "buffer": 0,
+            "byteOffset": 576,
+            "byteLength": 72,
+            "target": 34963
+        },
+        {
+            "buffer": 0,
+            "byteOffset": 0,
+            "byteLength": 576,
+            "byteStride": 12,
+            "target": 34962
+        }
+    ],
+    "buffers": [
+        {
+            "byteLength": 648,
+            "uri": "data:application/octet-stream;base64,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"
+        }
+    ]
+}

Specs/Scene/ModelSpec.js

@@ -120,6 +120,7 @@ defineSuite([
 
     var boomBoxUrl = './Data/Models/PBR/BoomBox/BoomBox.gltf';
     var boxPbrUrl = './Data/Models/PBR/Box/Box.gltf';
+    var boxPbrUnlitUrl = './Data/Models/PBR/BoxUnlit/BoxUnlit.gltf';
     var boxAnimatedPbrUrl = './Data/Models/PBR/BoxAnimated/BoxAnimated.gltf';
     var boxInterleavedPbrUrl = './Data/Models/PBR/BoxInterleaved/BoxInterleaved.gltf';
     var riggedSimplePbrUrl = './Data/Models/PBR/RiggedSimple/RiggedSimple.gltf';
@@ -2693,6 +2694,21 @@ defineSuite([
         });
     });
 
+    it('renders with the unlit extension', function() {
+        return loadModel(boxPbrUnlitUrl).then(function(model) {
+            model.show = true;
+            model.zoomTo();
+            // We expect to see the base color when unlit
+            expect(scene).toRenderAndCall(function(rgba) {
+                expect(rgba[0]).toEqual(0);
+                expect(rgba[1]).toEqual(255);
+                expect(rgba[2]).toEqual(0);
+            });
+
+            primitives.remove(model);
+        });
+    });
+
     it('silhouetteSupported', function() {
         expect(Model.silhouetteSupported(scene)).toBe(true);
         scene.context._stencilBits = 0;