Here I want to show how transparency and lighting both and separately change the look of a surface. So, there is code and picture for that:
int sample(mglGraph *gr) { mglData a; mgls_prepare2d(&a); gr->SubPlot(2,2,0); gr->Title("default"); gr->Rotate(50,60); gr->Box(); gr->Surf(a); gr->SubPlot(2,2,1); gr->Title("light on"); gr->Rotate(50,60); gr->Box(); gr->Light(true); gr->Surf(a); gr->SubPlot(2,2,3); gr->Title("alpha on; light on"); gr->Rotate(50,60); gr->Box(); gr->Alpha(true); gr->Surf(a); gr->SubPlot(2,2,2); gr->Title("alpha on"); gr->Rotate(50,60); gr->Box(); gr->Light(false); gr->Surf(a); return 0; }