环境设定

• The IG plugin API section for more details on managing IG via code (C++)这IG插件API部分，了解有关通过代码管理IG的更多详细信息（C ++）
• SkyMap class for more details on managing sky and celestial bodies via code (C++)SkyMap类，以获取有关通过代码管理天空和天体的更多详细信息（C ++）
• Meteo class for more details on managing global weather settings via code (C++)Meteo类，以获取有关通过代码（C ++）管理全球天气设置的更多详细信息
• Region class for more details on managing weather regions via code (C++)Region类，以获取有关通过代码管理天气区域的更多详细信息（C ++）

Star field intensity might seem too low by default. You may need to adjust brightness level of your displays or increase maximum brightness of the star field for your area.默认情况下，星场强度非常低。您可能需要调整显示器的亮度级别或增加所在区域星空的最大亮度。

To set up the stars and make them look brighter do the following: 要使星星看起来更明亮，请执行以下操作：

• Temporarily disable the sun node in the IG:DateTime window of the IG Editor Plugin and make sure the Stars intensity is set to high value. 暂时禁用编辑器中的sun节点
• Open Environment Settings (Windows -> Settings -> Runtime/World/Render/Environment).打开环境设定（Windows -> Settings -> Runtime/World/Render/Environment）
• Set the Environment Texture to stars_c.hdr.确保将Environment Texture设置为star_c.hdr

• Click Environment Color and increase values of RGB color components until you reach the desired color and brightness of the star field (e.g., to 100,100,100).单击Environment Color并增加RGB颜色分量的值，直到达到所需的星场亮度（例如，达到100,100,100）。

  注意

  The Alpha channel is used by the system to control Star Intensity (e.g., via CIGI).系统使用Alpha通道来控制恒星强度（例如，通过CIGI）。
• Enable the sun node back again and save your world.再次启用sun节点并保存您的世界。

Stars are positioned on the sky automatically, depending on the date/time and geographic location.根据日期/时间和地理位置，星星会自动定位在天空上。

IG has a built-in celestial body control (celestial_control packet). In order to use it, you should have:IG具有内置的天体控件（celestial_control数据包）。为了使用它，您应该具有：

• Two nodes, one for the Sun, and one for the Moon两个节点，一个用于太阳，一个用于月球
• The Celestial property assigned to the sun node分配给sun节点的Celestial属性
• Parameters of the Celestial property containing links to the corresponding nodes.Celestial属性的参数包含指向相应节点的链接。

Positions of the Sun and the Moon are adjusted automatically depending on the date/time and geographic location.太阳和月亮的位置会根据日期/时间和地理位置自动调整。

Sometimes it may be necessary to perform certain actions when the state of the sky changes (e.g. enable lighting at nignt time). Callbacks can be used for this purpose. Just implement your specific actions in a callback function and set it as follows:有时，当天空状态发生变化时，可能有必要执行某些操作（例如，在零时启用照明）。回调可用于此目的。只需在回调函数中实现您的特定操作，然后进行如下设置即可：

/// callback function to be called when sky state changes
void SomeClass::my_callback()
{
	// pointer to your sun node (don't forget to initialize it)
	NodePtr sun;
	
	// calculating zenith angle to determine if it is night time or not
	float zenith = getAngle(vec3_up, sun->getDirection(AXIS_Z));
	bool night = zenith > sun_zenit_threshold;
	
	// switching lights
	for (auto & it : lights)
	{
		it.data.setEnable(night);
	}
	
	// switching the emission state for emissive materials
	for (auto & it : emissive_materials)
	{
		it->setState("emission",night);
	}			
}

// ...
// somewhere in code
void SomeClass::init()
{
	// adding "my_callback" to be called on changing sky state
	ig_manager->getSkyMap()->addCallbackRefresh(this, Unigine::MakeCallback(this, &SomeClass::my_callback ) );
}

Weather regions represent the shape of weather in certain areas from the top-down view (cyclone, turbulence zone, thunderstorm front). Various custom weather layers can be added to a region on demand.体积云是模拟光吸收的粒子团，在流经时会导致可见度的实际降低。云会在地形上蒙上阴影。

The type of region specify its shape:IG当前支持Stratocumulus和Stratus云（根据CIGI规范，类型为9和10），但是您可以通过继承clouds_base的新材质来扩展此集合。

There is always a Global region present in the world. The number of possible regions is unlimited.使用接收到的weather_control数据包中的Coverage值自动设置云覆盖，或者您可以通过以下代码手动更改它：

// setting cloud coverage for weather region with a given id
ig_manager->getMeteo()->getRegion(region_id)->setCloudDensity(density_value);

注意

积雨云（Cumulonimbus 1，Cumulonimbus 2，Cumulonimbus 3）由于其特定的功能而无法通过Coverage参数进行控制-这种类型的云始终具有有限的边界并且不能是全局的。

云的覆盖范围不会立即发生变化，它具有一定的过渡期，可提供平滑性。您可以通过更改以下位置的cloud_transition_time标记中的值来调整过渡时间：配置文件（data/ig_config.xml）。

可以在LightingProperties属性（data/ig/weather/properties/LightingProperties.prop）中找到闪电参数。

以下内容可供调整：

• Period —后续闪电之间的间隔，以秒为单位。
• Emission Params —定义雷电发射特性的一组参数：
  • 前两个是emission_random_factor_min和emission_random_factor_max-这些值定义了随机闪光强度的极限（与闪电材料的Emission Scale参数值的最小和最大偏差）。
  • emission_period —定义单个闪光灯的寿命，以秒为单位。此值应始终小于后续闪烁之间的间隔。

To adjust specific parameters for rain or snow (spawn rate, size of raindrops/snowflakes, etc.) select the IG precipitation node in the World Nodes window and tweak the parameters of the PrecipitationEffect property assigned to it.要调整降雨或降雪的参数（强度，雨滴/雪花的大小等），请选择场景中的相应节点并调整分配给它的PrecipitationParams属性的参数。

The following parameters are available:可以使用以下参数：

• Precipitation Type — type of precipitation (rain or snow).Minimum Intensity 和Maximum Intensity-这些值定义了降雨或降雪的随机强度极限。
• Emitter Node — particles node that simulates the effect.Minimum Particle Size和Particle Size-这些值定义雨滴或雪花的大小变化。
• Minimum and Maximum Particles Size — limits for random particles size.Source Node —表示场景中的雨或雪的节点。
• Minimum and Maximum Spawn Rate — limits for spawn rate value.Lut Base Image —基本散射LUT要使用的。
• Rotation — rotation parameters for particles based on the camera movement.
  • Enabled — enables the particles rotation.
  • Curve — sets the interpolation curve for rotation (linear interpolation when the curve is not specified).
  • Curve Angle Scale — maximum deflection angle.
  • Curve Speed Scale — maximum speed when the maximum deflection angle is achieved.
  Lut Mie Image —三重散射LUT要使用的。

Particle Systems (rain, snow, and so on) can be affected by the wind controlled by IG when they get inside a region with wind enabled. Wind also affects the cloud movement in cloud layers.粒子系统可能会受到IG控制的风的影响。这是通过分配ParticlesWind属性来实现的。

可以使用以下参数：

• Recursive —将所有子粒子系统与分配了此属性的父粒子系统同步。子粒子系统不需要分配此属性。
• Gravity Vertical —控制粒子下落速度的重力值。

For your convenience, we have also added the windsock.node asset to the IG Template, it is available in ig_data\objects\windsock\.为了方便起见，我们还将windsock.node资产添加到IG模板中，该资产在data\ig\objects\windsock\中可用。

This asset is already preconfigured to be affected by the IG wind via the WindSock property.此资产已通过WindSock属性预先配置为受IG风影响。

The following parameters are available:可以使用以下参数：

• Angle Wind — additional angle rotating the mesh to align it with the wind direction.Angle Wind —旋转网格以使其与风向对齐的附加角度。
• Mesh Skinned — the windsock mesh.Mesh Skinned —风向袋网格。
• Anim Power — animation of the windsock deformation depending on the wind speed variation.Anim Power —风向袋变形的动画，取决于风速变化。
• Anim Standing — animation of the windsock rippling.Anim Standing —风向袋荡漾的动画。

有时，当天气条件发生变化时，可能有必要执行某些操作（例如，为风向袋或风向标设定方向）。可以使用与for相同的方法来使用回调改变天空状态。只需在回调函数中实现您的特定操作，然后进行如下设置即可：

/// callback function to be called when weather conditions change
void SomeClass::my_weather_callback()
{
	// setting orientation of the vane downwind
	vec3 wind_direction = ig_manager->getMeteo()->getMeanWindSpeed(vane_node->getWorldPosition());
	vane_node->setWorldDirection(wind_direction, vec3_up);
}

// ...
// somewhere in code
void SomeClass::init()
{
	// adding "my_weather_callback" to be called on changing weather conditions
	ig_manager->getMeteo()->addCallbackMeteoChanged(this, Unigine::MakeCallback(this, &SomeClass::my_weather_callback );
}