Write position bounds to gltf file.

source/export/exportergltf.js

@@ -267,6 +267,7 @@ OV.ExporterGltf = class extends OV.ExporterBase
                     material : primitive.material
                 };
                 
+                let bounds = primitive.GetBounds ();
                 mainJson.accessors.push ({
                     bufferView : bufferViewIndex,
                     byteOffset : 0,
@@ -279,6 +280,8 @@ OV.ExporterGltf = class extends OV.ExporterBase
                     byteOffset : 0,
                     componentType : this.components.number.type,
                     count : primitive.vertices.length / 3,
+                    min : bounds.min,
+                    max : bounds.max,
                     type : 'VEC3'
                 });
                 mainJson.accessors.push ({

source/model/meshbuffer.js

@@ -9,6 +9,22 @@ OV.MeshPrimitiveBuffer = class
         this.material = null;
     }
 
+    GetBounds ()
+    {
+        let min = [Infinity, Infinity, Infinity];
+        let max = [-Infinity, -Infinity, -Infinity];
+        for (let i = 0; i < this.vertices.length / 3; i++) {
+            for (let j = 0; j < 3; j++) {
+                min[j] = Math.min (min[j], this.vertices[i * 3 + j]);
+                max[j] = Math.max (max[j], this.vertices[i * 3 + j]);
+            }
+        }
+        return {
+            min : min,
+            max : max
+        }
+    }
+
     GetByteLength (indexTypeSize, numberTypeSize)
     {
         let indexCount = this.indices.length;