Duplicate materials with mismatching attributes

CHANGES.md

@@ -2,7 +2,8 @@ Change Log
 ==========
 
 ### 2.3.2 ????-??-??
-
+* Improved handling of primitives with different attributes using the same material. Materials are now duplicated. [#162](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/162)
+* Fixed a bug where primitives without texture coordinates could use materials containing textures. Those textures are now removed. [#162](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/162)
 * Improved parsing of faces with mismatching attributes. [#161](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/161)
 
 ### 2.3.1 2018-10-16

lib/createGltf.js

@@ -4,6 +4,7 @@ var getBufferPadded = require('./getBufferPadded');
 var getDefaultMaterial = require('./loadMtl').getDefaultMaterial;
 var Texture = require('./Texture');
 
+var defaultValue = Cesium.defaultValue;
 var defined = Cesium.defined;
 var WebGLConstants = Cesium.WebGLConstants;
 
@@ -23,6 +24,9 @@ function createGltf(objData, options) {
     var materials = objData.materials;
     var name = objData.name;
 
+    // Split materials used by primitives with different types of attributes
+    materials = splitIncompatibleMaterials(nodes, materials, options);
+
     var gltf = {
         accessors : [],
         asset : {},
@@ -70,14 +74,14 @@ function createGltf(objData, options) {
         var meshIndex;
 
         if (meshesLength === 1) {
-            meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, meshes[0], options);
+            meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, meshes[0]);
             addNode(gltf, node.name, meshIndex, undefined);
         } else {
             // Add meshes as child nodes
             var parentIndex = addNode(gltf, node.name);
             for (var j = 0; j < meshesLength; ++j) {
                 var mesh = meshes[j];
-                meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, mesh, options);
+                meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, mesh);
                 addNode(gltf, mesh.name, meshIndex, parentIndex);
             }
         }
@@ -194,6 +198,31 @@ function getTexture(gltf, texture) {
     };
 }
 
+function cloneMaterial(material, removeTextures) {
+    if (typeof material !== 'object') {
+        return material;
+    } else if (material instanceof Texture) {
+        if (removeTextures) {
+            return undefined;
+        }
+        return material;
+    } else if (Array.isArray(material)) {
+        var length = material.length;
+        var clonedArray = new Array(length);
+        for (var i = 0; i < length; ++i) {
+            clonedArray[i] = cloneMaterial(material[i], removeTextures);
+        }
+        return clonedArray;
+    }
+    var clonedObject = {};
+    for (var name in material) {
+        if (material.hasOwnProperty(name)) {
+            clonedObject[name] = cloneMaterial(material[name], removeTextures);
+        }
+    }
+    return clonedObject;
+}
+
 function resolveTextures(gltf, material) {
     for (var name in material) {
         if (material.hasOwnProperty(name)) {
@@ -207,48 +236,99 @@ function resolveTextures(gltf, material) {
     }
 }
 
-function addMaterial(gltf, material) {
+function addGltfMaterial(gltf, material) {
     resolveTextures(gltf, material);
     var materialIndex = gltf.materials.length;
     gltf.materials.push(material);
     return materialIndex;
 }
 
-function getMaterial(gltf, materials, materialName, options) {
-    if (!defined(materialName)) {
-        // Create a default material if the primitive does not specify one
-        materialName = 'default';
+function getMaterialByName(materials, materialName) {
+    var materialsLength = materials.length;
+    for (var i = 0; i < materialsLength; ++i) {
+        if (materials[i].name === materialName) {
+            return materials[i];
+        }
     }
+}
 
-    var i;
-    var material;
+function getMaterialIndex(materials, materialName) {
     var materialsLength = materials.length;
-    for (i = 0; i < materialsLength; ++i) {
+    for (var i = 0; i < materialsLength; ++i) {
         if (materials[i].name === materialName) {
-            material = materials[i];
-            break;
+            return i;
         }
     }
+}
+
+function getOrCreateGltfMaterial(gltf, materials, materialName) {
+    var material = getMaterialByName(materials, materialName);
+    var materialIndex = getMaterialIndex(gltf.materials, materialName);
 
-    if (!defined(material)) {
-        material = getDefaultMaterial(options);
-        material.name = materialName;
+    if (!defined(materialIndex)) {
+        materialIndex = addGltfMaterial(gltf, material);
     }
 
-    var materialIndex;
-    materialsLength = gltf.materials.length;
-    for (i = 0; i < materialsLength; ++i) {
-        if (gltf.materials[i].name === materialName) {
-            materialIndex = i;
+    return materialIndex;
+}
+
+function primitiveInfoMatch(a, b) {
+    return a.hasUvs === b.hasUvs &&
+           a.hasNormals === b.hasNormals;
+}
+
+function getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial) {
+    var splitMaterialName = originalMaterialName;
+    var suffix = 2;
+    while (defined(primitiveInfoByMaterial[splitMaterialName])) {
+        if (primitiveInfoMatch(primitiveInfo, primitiveInfoByMaterial[splitMaterialName])) {
             break;
         }
+        splitMaterialName = originalMaterialName + '-' + suffix++;
     }
+    return splitMaterialName;
+}
 
-    if (!defined(materialIndex)) {
-        materialIndex = addMaterial(gltf, material);
-    }
+function splitIncompatibleMaterials(nodes, materials, options) {
+    var splitMaterials = [];
+    var primitiveInfoByMaterial = {};
+    var nodesLength = nodes.length;
+    for (var i = 0; i < nodesLength; ++i) {
+        var meshes = nodes[i].meshes;
+        var meshesLength = meshes.length;
+        for (var j = 0; j < meshesLength; ++j) {
+            var primitives = meshes[j].primitives;
+            var primitivesLength = primitives.length;
+            for (var k = 0; k < primitivesLength; ++k) {
+                var primitive = primitives[k];
+                var hasUvs = primitive.uvs.length > 0;
+                var hasNormals = primitive.normals.length > 0;
+                var primitiveInfo = {
+                    hasUvs : hasUvs,
+                    hasNormals :  hasNormals
+                };
+                var originalMaterialName = defaultValue(primitive.material, 'default');
+                var splitMaterialName = getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial);
+                primitive.material = splitMaterialName;
+                primitiveInfoByMaterial[splitMaterialName] = primitiveInfo;
+
+                var splitMaterial = getMaterialByName(splitMaterials, splitMaterialName);
+                if (defined(splitMaterial)) {
+                    continue;
+                }
 
-    return materialIndex;
+                var originalMaterial = getMaterialByName(materials, originalMaterialName);
+                if (defined(originalMaterial)) {
+                    splitMaterial = cloneMaterial(originalMaterial, !hasUvs);
+                } else {
+                    splitMaterial = getDefaultMaterial(options);
+                }
+                splitMaterial.name = splitMaterialName;
+                splitMaterials.push(splitMaterial);
+            }
+        }
+    }
+    return splitMaterials;
 }
 
 function addVertexAttribute(gltf, array, components, name) {
@@ -309,7 +389,7 @@ function requiresUint32Indices(nodes) {
     return false;
 }
 
-function addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitive, index, options) {
+function addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitive, index) {
     var hasPositions = primitive.positions.length > 0;
     var hasNormals = primitive.normals.length > 0;
     var hasUVs = primitive.uvs.length > 0;
@@ -346,7 +426,7 @@ function addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primiti
     primitive.uvs = undefined;
     primitive.indices = undefined;
 
-    var materialIndex = getMaterial(gltf, materials, primitive.material, options);
+    var materialIndex = getOrCreateGltfMaterial(gltf, materials, primitive.material);
 
     return {
         attributes : attributes,
@@ -356,12 +436,12 @@ function addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primiti
     };
 }
 
-function addMesh(gltf, materials, bufferState, uint32Indices, mesh, options) {
+function addMesh(gltf, materials, bufferState, uint32Indices, mesh) {
     var gltfPrimitives = [];
     var primitives = mesh.primitives;
     var primitivesLength = primitives.length;
     for (var i = 0; i < primitivesLength; ++i) {
-        gltfPrimitives.push(addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitives[i], i, options));
+        gltfPrimitives.push(addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitives[i], i));
     }
 
     var gltfMesh = {

specs/data/box-mixed-attributes-2/box-mixed-attributes-2.mtl

@@ -0,0 +1,13 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2
+map_Kd cesium.png

specs/data/box-mixed-attributes-2/box-mixed-attributes-2.obj

@@ -0,0 +1,67 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-mixed-attributes-2.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+# Using default material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+usemtl Material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+usemtl Missing
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+o CubeCopy
+usemtl Material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6