26.3 Generic OpenGL code

Let's look at an example of the kinds of calls that we feed into the OpenGL state-machine hopper so as to prepare to draw something. Specifically, let's see what it would take to draw a white square.

//Initialize the Window (Described in next subsection) 
::glClearColor(0.0, 0.0, 0.0, 0.0); 
::glClear(GL_COLOR_BUFFER_BIT); 
::glColor3f(1.0, 1.0, 1.0); 
::glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0); 
::glBegin(GL_POLYGON) 
    ::glVertex(0.25, 0.25, 0.0); 
    ::glVertex(0.75, 0.25, 0.0); 
    ::glVertex(0.75, 0.75, 0.0); 
    ::glVertex(0.25, 0.75, 0.0); 
::glEnd(); 
::glFinish(); 
//Update the Window (Described in next subsection) 

You can view a lot more code like this in the Pop Framework's graphicsopengl.cpp file.