I'm not sure what you mean about texcoords, but yeah you have to duplicate the colors in the array. Basically, for one api call such as glDrawElements(), it's all or nothing. Either you have the color array activated and you submit a color for each vert, or you deactivate the color array and set an overall color with glColor**(). So it's not really a waste of time. The api doesn't care whether the colors are the same or different - it's going to access them in the array either way.