When rendering for most output devices (monitors or televisions), the device only supports a typical color precision of 8-bits per color component, or 24-bits per pixel. Therefore, for a given color component, we're limited to a range of intensities between 0 and 255. Internally, OpenGL uses floating-point values for color intensities, providing a wide range of both values and precision. These are eventually converted to 8-bit values by mapping the floating-point range [0.0, 1.0] to the range of an unsigned byte [0, 255] before rendering.
Real scenes, however, have a much wider range of luminance. For example, light sources that are visible in a scene, or direct reflections of them, can be hundreds ...
