calculate and write min and max attributes for accessors

code/glTFAsset.h

@@ -377,8 +377,8 @@ namespace glTF
         ComponentType componentType; //!< The datatype of components in the attribute. (required)
         unsigned int count;          //!< The number of attributes referenced by this accessor. (required)
         AttribType::Value type;      //!< Specifies if the attribute is a scalar, vector, or matrix. (required)
-        //std::vector<float> max;    //!< Maximum value of each component in this attribute.
+        std::vector<float> max;      //!< Maximum value of each component in this attribute.
-        //std::vector<float> min;    //!< Minimum value of each component in this attribute.
+        std::vector<float> min;      //!< Minimum value of each component in this attribute.
 
         unsigned int GetNumComponents();
         unsigned int GetBytesPerComponent();

code/glTFAssetWriter.inl

@@ -62,6 +62,15 @@ namespace glTF {
             return val;
         }
 
+        inline Value& MakeValue(Value& val, const std::vector<float> & r, MemoryPoolAllocator<>& al) {
+            val.SetArray();
+            val.Reserve(r.size(), al);
+            for (int i = 0; i < r.size(); ++i) {
+                val.PushBack(r[i], al);
+            }
+            return val;
+        }
+
         template<class T>
         inline void AddRefsVector(Value& obj, const char* fieldId, std::vector< Ref<T> >& v, MemoryPoolAllocator<>& al) {
             if (v.empty()) return;
@@ -85,6 +94,10 @@ namespace glTF {
         obj.AddMember("componentType", int(a.componentType), w.mAl);
         obj.AddMember("count", a.count, w.mAl);
         obj.AddMember("type", StringRef(AttribType::ToString(a.type)), w.mAl);
+
+        Value vTmpMax, vTmpMin;
+        obj.AddMember("max", MakeValue(vTmpMax, a.max, w.mAl), w.mAl);
+        obj.AddMember("min", MakeValue(vTmpMin, a.min, w.mAl), w.mAl);
     }
 
     inline void Write(Value& obj, Animation& a, AssetWriter& w)
@@ -491,7 +504,7 @@ namespace glTF {
         asset.SetObject();
         {
             char versionChar[10];
-            snprintf(versionChar, sizeof(versionChar), "%d", mAsset.asset.version);
+            ai_snprintf(versionChar, sizeof(versionChar), "%d", mAsset.asset.version);
             asset.AddMember("version", Value(versionChar, mAl).Move(), mAl);
 
             asset.AddMember("generator", Value(mAsset.asset.generator, mAl).Move(), mAl);

code/glTFExporter.cpp

@@ -193,6 +193,31 @@ inline Ref<Accessor> ExportData(Asset& a, std::string& meshName, Ref<Buffer>& bu
     acc->count = count;
     acc->type = typeOut;
 
+    // calculate min and max values
+    {
+        // Allocate and initialize with large values.
+        float float_MAX = 10000000000000;
+        for (int i = 0 ; i < numCompsOut ; i++) {
+            acc->min.push_back( float_MAX);
+            acc->max.push_back(-float_MAX);
+        }
+
+        // Search and set extreme values.
+        float valueTmp;
+        for (int i = 0 ; i < count       ; i++) {
+        for (int j = 0 ; j < numCompsOut ; j++) {
+
+            valueTmp = static_cast<aiVector3D*>(data)[i][j];
+            if (valueTmp < acc->min[j]) {
+                acc->min[j] = valueTmp;
+            }
+            if (valueTmp > acc->max[j]) {
+                acc->max[j] = valueTmp;
+            }
+        }
+        }
+    }
+
     // copy the data
     acc->WriteData(count, data, numCompsIn*bytesPerComp);