Tone Mapping ¶

Most monitors are capable of displaying RGB values in the range of [0, 255]. However, in real life, there is no limit on the amount of light ’energy’ incident on a point. Most renderers output linear radiance values in [0, ∞), which needs to be mapped into a viewable range. Those radiance values are described as High Dynamic Range (HDR), because they are unlimited, and the viewable target range is described as Low Dynamic Range (LDR), because there is a fixed limit of 255. Put simply, tone mapping is the process of mapping HDR values in [0, ∞) into LDR values (e.g values in [0, 255] or [0.0, 1.0]).
Matt Taylor, 2019

Usage ¶

const toneMappingEffect = new ToneMappingEffect({
  toneMapping: ToneMapping.AGX // default
});

Tip

Tone mapping should generally be applied late in a render pipeline, but before anti-aliasing and the final color space conversion.

Primary Color Grading ¶

The ToneMappingEffect uses the American Society of Cinematographers Color Decision List (ASC CDL) format to configure primary color grading information. This format defines the math for Slope, Offset, Power and Saturation and provides a way to influence the look of the tone-mapped image.

Info

Only ToneMapping.AGX currently supports CDL parameters.

External Resources ¶

• Tone Mapping Techniques
• ASC CDL