Lumberyard
User Guide (Version 1.15)

HDR Settings

As discussed in Illuminance and Auto Exposure Key, the auto exposure key setting controls the amount of scene exposure and determines whether the tone-mapped image appears relatively bright or dark. Several other settings also affect the tone mapping of scene. These are known collectively as HDR (high dynamic range) in the Time of Day Editor.

Film curve parameters in the Time of Day Editor correspond to analogous parameters that exist for camera film. A film curve has three distinct regions with different contrast transfer characteristics:

  • The lower part of a film curve that is associated with relatively low exposures is designated the toe, and corresponds to the low-density portions of an image. When an image is exposed so that areas fall within the toe region, little or no contrast is transferred to the image.

  • The upper part of a film curve that is associated with relatively high exposures is designated the shoulder, and corresponds to the high-density portions of an image. When an image is exposed so that areas fall within the shoulder region, little or no contrast is transferred to the image.

  • The middle part of a film curve with the highest level of contrast is produced within a range of exposures falling between the toe and the shoulder, and is designated the midtones region. This portion of the curve is characterized by a relatively straight and steep slope in comparison to the toe and shoulder regions. You should adjust your image so that important areas fall within this region for maximum contrast.

To set HDR settings parameters

  1. In Lumberyard Editor, click Tools, Other, Time Of Day.

  2. Under Time of Day Tasks, click Toggle Advanced Properties to view all settings.

  3. Under HDR Settings, HDR, click and adjust the values of the following settings:

    Film curve shoulder scale

    Slope at the tip of the HDR curve (modifies bright values).

    Film curve midtones scale

    Linearity of the middle of the HDR curve (modifies gray values).

    Film curve toe scale

    Slope at the base of the curve (modifies dark values).

    Film curve whitepoint

    Value to be mapped as pure white or reference white in the tone-mapped image.

    Saturation

    Color saturation before tone-mapping.

    Color balance

    Overall color of the scene.

    Auto Exposure Key

    Overall brightness of the scene used for eye adaptation. Eye adaptation causes the exposure of a scene to simulate the way human eyes adjust when going from a brightly lit environment to a dark environment and vice versa. Use lower value for dark scenes and higher values for bright scenes. Default value is 0.18.

    Auto Exposure Min

    Darkest possible exposure used for eye adaptation.

    Auto Exposure Max

    Brightest possible exposure used for eye adaptation.

    Bloom amount

    Controls the amount of bloom that comes from glowing or lit objects.