remove duplicate user_data vector from world_vertex

update max. number of vertex attributes
to avoid user data getting "reused" across mesh draws

gl/vao.cpp

@@ -66,7 +66,7 @@ void gl::vao::bind()
 			glEnableVertexAttribArray(param.attrib);
 		}
 
-		for (size_t i = params.size(); i < 4; i++)
+		for (size_t i = params.size(); i < 5; i++)
 			glDisableVertexAttribArray(i);
 
 		if (ebo)

vertex.h

@@ -18,7 +18,6 @@ struct world_vertex {
     glm::dvec3 position;
     glm::vec3 normal;
     glm::vec2 texture;
-	glm::vec4 user_data;
 
 // overloads
     // operator+