Typically, the scene is gouraud shaded, hidden surfaces are removed and lighting is incorporated without shadows. The amount of finesse depends on the installed graphics hardware. Sometimes called back-culling . Hardware render is very fast but the output quality is usually acceptable only to real-time simulation applications. Consider an imaginary picture plane placed between the eye and the scene.
Picture plane consists of a grid of pixels.
Grid resolution depends on the size of the the image to be rendered. For every pixel on the grid there is a ray cast from the eye, through the grid, to the scene. If the ray does not hit anything, it is set to the background color, which is usually black. If it hits an object it checks if it is lit at that pixel and from what angle. The closer the angle is to 90 degrees the bigger the intensity.