Embodiments of the present invention are directed to rendering computer graphics using an augmented direct light model which approximates the effect of indirect light in shadows. More specifically, a shadow illuminator light source is provided for. The shadow illuminator light source is associated with an ordinary, or primary light source and is used to provide illumination in areas which are in shadows with respect to the primary light source. The shadow illuminator provides illumination only to areas which are considered to be in the shadows with respect to the light source the shadow illuminator is associated with. Thus, the shadow illuminator may be used to approximate the effects of indirect light.