Drawing with glColor3ui, Blank Screen

Hi I’m having trouble getting pixels to draw in 2D with glColor3ui, seems to work with glColor3f though. The screen
just comes up blank

Init code


if ( (SDL_Init( SDL_INIT_VIDEO | SDL_INIT_AUDIO ) == -1 ) ) 
	{
		printf("Could not initialize SDL: %s.
", SDL_GetError()); 
		exit(-1);
	}
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 32);

	screen.image = SDL_SetVideoMode(640, 480, 32, SDL_OPENGL|SDL_FULLSCREEN);  	

	glClearColor(0.0,0.0,0.0,0.0);
	SDL_GL_SwapBuffers();

	glViewport(0,0,640,480);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	gluOrtho2D(0,640,480,0);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();

Drawing Code


        colour.G=0;

	for(d=0;d<200;d++)
	{
		colour.G++;
		glBegin(GL_POINTS);
		        glColor3ui(colour.R,colour.G,colour.B);
			glVertex2i(640/2+d,480/2);
		glEnd();
	}

ui means unsigned int, color ranges from 0 to 4.2 billion.
f means float, color range is normalized from 0.0f to 1.0f.

working with ub is often more realistic, as it matches the 16.7 million colors of typical display. Color range is 0 to 255 in this case.

means 1.0f is converted to unsigned int 1 instead of 255 which is like the closest step to complete black (0).