Basic knowledge about HDR

You can open the Environment Editor by pressing the F6 key

Key components for HDR lighting

The following sections must be enabled in the environment preset settings:

• eye_adaptation - enabled

• tone_mapping - enabled

• tone_mapping - aces

The main HDR parameter is target_exposure in the eye_adaptation section.

Key components for the HDR lighting

Conditions for correct HDR operation

For HDR to function properly, there must be light at varying brightness ranges, with screen brightness differing by at least 5-10 times.

The working range is from 0.001 to 10.

Lighting components

Component	Description
light.ambient_intensity	Intensity of ambient lighting that spreads evenly across the scene.
light.diffuse_intensity	Intensity of diffuse lighting that determines the brightness of surfaces facing the light source.
light.envmap_amount	Amount of light reflected from the environmental map, used for creating reflections.
light.environment_intensity	Intensity of lighting from the environment, including natural and reflected light.
haze.intensity	Intensity of haze or fog, adding an atmospheric effect and altering scene visibility.
HDR sky textures	Use of high dynamic range textures for the sky to achieve realistic light transitions.
Quadratic attenuation in light sources	A light attenuation formula that realistically distributes light as distance increases.
Speculars for all materials	Adjustment of specular properties for all materials, adding highlights and reflected light

The final color for lighting parameters containing intensity (e.g., light.ambient, light.diffuse, haze.color, and others) is calculated using the formula:

result_color = color * intensity

The final brightness depends on the brightness of the color itself and the intensity parameter

Examples of lighting parameter settings, including color and its intensity

Real-life brightness levels

Parameter	Light Intensity	Description
candle	10	Imitation of candle light, creating a cozy atmosphere
cloud_at_night	0.00033	Dim lighting under a cloudy night sky
cloud_at_night (lit by moon)	0.0419	Cloudy night sky illuminated by the moon
frosted_bulb_60w	1200	Light from a 60-watt frosted bulb
monitor	3	Imitation of light from a monitor
moon_surface	30	Light mimicking the luminosity of the moon's surface
sky_cloudy	20	Light on a cloudy day
sky_day	60	Bright sunlight during the day
sky_night (lit by moon)	0.00085	Night light when illuminated by the moon
sky_night_dark	4e-006	Very dim night lighting
sky_night_noon	0.00124	Night lighting without additional light sources
sky_rise_skyline	0.0019	Dawn or dusk
star	0.00196	Light from a distant star

Tonemapper settings

Tonemapper settings should be the same across the entire project

If you need a specific frame appearance - use a LUT.

For understanding the operation of adaptation and HDR, it is very useful to enable the display of curves for HDR parameters using the console command v_hdrHistogramOn 1

Fig 1. Tonemapper curve

Decoding Figure 1:

• Red line - tonemapping curve (automatically calculated by the tonemapping formula and its parameters)

• Yellow line - brightness value selected by auto exposure

• Green lines - exposure_min, exposure_max

• Blue lines - horizontal brightness readings

Objects for testing color

To test colors in game resources, there are 3 test entity located in the service folder of the Entity Editor [1]:

• color_checker_gradient - for testing the display of monochrome gradients

• color_checker_kodak - for testing brightness levels

• color_checker - for testing the transmission of standard shades

Learn more about creating and configuring environment presets

Step-by-step guide to developing custom environment presets

Creating environment preset

Detailed instructions for fine-tuning environment presets

Setting Environment preset parameters