.. _stdlib_distance_fog_component:

===========
DistanceFog
===========


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Enumerations
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.. _enum-public_components-DistanceFogLightingMode:

.. das:attribute:: DistanceFogLightingMode

:Values: * **None** = 0 - No lighting is applied to fog and just raw color is taken.

         * **Ambient** = 1 - Ambient light at view direction is applied to fog, simulating inscattering of light coming from the environment.


.. _enum-public_components-DistanceFogMode:

.. das:attribute:: DistanceFogMode

:Values: * **Linear** = 0 - Linear fading in range ``[startDistance, startDistance + 1 / (1 - density) - 1]``. Cheapest to compute.

         * **Exponential** = 1 - Exponential fading starting from ``startDistance`` according to formula ``exp2(-(1 / (1 - density) - 1) * (distance - startDistance))``. This is a physically plausible way for representing light absorption. Also enables correct usage of height-based density.

         * **ExponentialSquared** = 2 - Exponential fading starting from ``startDistance`` according to formula ``exp2(-pow((1 / (1 - density) - 1) * (distance - startDistance), 2))``. May be useful for producing smooth yet short transition into the fog without visible edges at ``startDistance``.


+++++++
Classes
+++++++

.. _struct-distance_fog_component-DistanceFog:

.. das:attribute:: DistanceFog : NativeComponent

This component is used to setup distance fog effect.
Distance fog is a non-physical effect with the primary use case of hiding away far parts of the scene.
But it can be a good cheap alternative to volumetric fog when no advanced lighting is required,
especiall with usage of height-based density.

To use this component, add the following line to your project file::

    require engine.core_components.distance_fog_component // or require engine.core

Usage example::

    let setting = create_render_settings()
    get_component(renderSettings) $(var fog : DistanceFog?) {
        fog.active = true
        fog.density = 0.005
        fog.lightingMode = DistanceFogLightingMode.Ambient
    }


:Properties:

.. _function-distance_fog_component__dot__rq_active_DistanceFog:

.. das:operator:: DistanceFog.active() : bool



.. _function-distance_fog_component__dot__rq_active_rq_clone_DistanceFog_bool:

.. das:operator:: DistanceFog.active =(value: bool)

Active flag. If set to true, distance fog will be applied to the result image. Default is false.

:Arguments: * **value** : bool

.. _function-distance_fog_component__dot__rq_mode_DistanceFog:

.. das:operator:: DistanceFog.mode() : DistanceFogMode



.. _function-distance_fog_component__dot__rq_mode_rq_clone_DistanceFog_DistanceFogMode:

.. das:operator:: DistanceFog.mode =(value: DistanceFogMode)

Approach used for computing fog amount at a certain depth. See DistanceFogMode enum description for details.

:Arguments: * **value** :  :ref:`DistanceFogMode <enum-public_components-DistanceFogMode>` 

.. _function-distance_fog_component__dot__rq_lightingMode_DistanceFog:

.. das:operator:: DistanceFog.lightingMode() : DistanceFogLightingMode



.. _function-distance_fog_component__dot__rq_lightingMode_rq_clone_DistanceFog_DistanceFogLightingMode:

.. das:operator:: DistanceFog.lightingMode =(value: DistanceFogLightingMode)

Approach used for lighting the fog. See DistanceFogLightingMode enum description for details.

:Arguments: * **value** :  :ref:`DistanceFogLightingMode <enum-public_components-DistanceFogLightingMode>` 

.. _function-distance_fog_component__dot__rq_color_DistanceFog:

.. das:operator:: DistanceFog.color() : float4



.. _function-distance_fog_component__dot__rq_color_rq_clone_DistanceFog_float4:

.. das:operator:: DistanceFog.color =(value: float4)

Color of the fog. Works as a multiplier to lighting if the latter is enabled.

:Arguments: * **value** : float4

.. _function-distance_fog_component__dot__rq_density_DistanceFog:

.. das:operator:: DistanceFog.density() : float



.. _function-distance_fog_component__dot__rq_density_rq_clone_DistanceFog_float:

.. das:operator:: DistanceFog.density =(value: float)

Desnsity of the fog in range [0, 1].

:Arguments: * **value** : float

.. _function-distance_fog_component__dot__rq_densityHeightFalloff_DistanceFog:

.. das:operator:: DistanceFog.densityHeightFalloff() : float



.. _function-distance_fog_component__dot__rq_densityHeightFalloff_rq_clone_DistanceFog_float:

.. das:operator:: DistanceFog.densityHeightFalloff =(value: float)

Falloff coefficient of density decrease with increase of altitude in range [0, 1]. Density multiplier at a height ``h`` is computed as ``exp((1 - 1 / (1 - densityHeightFalloff)) * (h - densityHeightOrigin))``. Note that height-based density computation is only correct for DistanceFogMode Exponential, although working with any mode.

:Arguments: * **value** : float

.. _function-distance_fog_component__dot__rq_densityHeightOrigin_DistanceFog:

.. das:operator:: DistanceFog.densityHeightOrigin() : float



.. _function-distance_fog_component__dot__rq_densityHeightOrigin_rq_clone_DistanceFog_float:

.. das:operator:: DistanceFog.densityHeightOrigin =(value: float)

Height at which density starts to decrease.

:Arguments: * **value** : float

.. _function-distance_fog_component__dot__rq_startDistance_DistanceFog:

.. das:operator:: DistanceFog.startDistance() : float



.. _function-distance_fog_component__dot__rq_startDistance_rq_clone_DistanceFog_float:

.. das:operator:: DistanceFog.startDistance =(value: float)

Distance from the camera at which the fog starts.

:Arguments: * **value** : float