Light Intensity,
Linear Attenuation,
Quadratic Attenuation
The point light and spot light can be set by the light intensity , linear attenuation and quadratic attenuation elements. The directional light can be set only by the light intensity . The resulting light intensity versus distance is given by the formula:
brightness = light_intensity / (1 + distance*linear_attenuation + distance^2*quadratic_attenuation)
The light intensity is an additional parameter to set the light color . By setting the light intensity in the range between 0 and 1 a similar effect of light intensity modification can be reached like that attained by the intensity regulation of individual color components of light. By setting the light intensity above 1, a higher light intensity can be reached than it would be possible by mere light color setting. In this manner it is possible to over-light the scene to reach special effects. By setting the light intensity under 0 the so called black light is created. This is a special effect that works as if the light would be "sucked" out of the scene. This effect is utilized when special effects should be reaches, as inverse scotopic vision.