add file picking for osx and ios and implement equirectangular import

engine/shape.h

@@ -194,4 +194,18 @@ public:
     }
 };
 
+class Sphere : public Shape
+{
+    void create_impl(int rings, int sectors, float radius, GLushort* idx, vertex_t* vertices);
+public:
+    template<int rings, int sectors>
+    bool create(float radius)
+    {
+        static GLushort idx[rings * sectors * 6];
+        static vertex_t vertices[rings * sectors];
+        create_impl(rings, sectors, radius, idx, vertices);
+        return create_buffers(idx, vertices, sizeof(idx), sizeof(vertices));
+    }
+};
+
 }