I am new in OpenGL. I tyr to write code in OpenGL so I examine sample codes. while examinig I can not understand What glMatrixMode does and How MatrixMode works. what is the difference GL_PROJECTION and GL_MODELVIEW . in the below jogl code ,why the first GL_PROJECTION, why not MODELVIEW. That is I can not understand.
GL gl = drawable.getGL ();
float aspect = (float) width/(float) height;
glu.gluPerspective (FOVY, aspect, NEAR, FAR);