diff --git a/qglview/glmaterial.h b/qglview/glmaterial.h
index 57fb96d..4f79a23 100644
--- a/qglview/glmaterial.h
+++ b/qglview/glmaterial.h
@@ -97,7 +97,8 @@ protected:
 
 };
 
-struct Map {
+class Map {
+public:
 	Map() {bitmap_id = 0; color_amount = 1.f; color_offset = 0.f; animation_frame_rate = -1.f;}
 	QString bitmap_path;
 	GLuint bitmap_id;
@@ -108,7 +109,8 @@ struct Map {
 	float animation_frame_rate;
 };
 
-struct Material {
+class Material {
+public:
 	Material();
 	void apply(QOpenGLShaderProgram * prog);
 	void loadTextures(GLTextureManagerBase * tm);