Other textures include oak plank on the floor, the image in the picture frame, the wallpaper, the pattern on the rug, and the cloth for the lamp shade. Figure 2 . This involves settings the position and attributes of the sources of light that affect the scene. Besides the ambient or background light level, there are generally four types of light source provided from which more complex sources can be made. Point light sources can be placed in the scene and radiate in all directions although they may have different distributions, circular and cylindrical say.
Directional sources provide for such things as torches or spot lights.
The angle or aperture of the cone is variable giving narrow or wide angle beams. Luminous surfaces cover such things as fluorescent surfaces, sometime referred to as the glow factor. All sources of course have an intensity attribute and often only white light is provided. Making coloured sources is accomplished by enclosing a white light source in a partially transparent coloured sphere. The sources can be positioned anywhere in the scene and made to point in some direction for directional sources.