Custom Shader Effects

OpenMW leverages the NiStringExtraData node to inject special shader flags and effects. This node must have the prefix omw:data and have a valid JSON object that follows.

Note

This is a new feature to inject OpenMW-specific shader effects. By default, the shader effects will propagate to all of a node’s children. Other propagation modes and effects will come with future releases.

Soft Effect

This effect softens the intersection of alpha-blended planes with other opaque geometry. This effect is automatically applied to all particle systems, but can be applied to any mesh or node. This is useful when layering many alpha-blended planes for various effects like steam over a hotspring or low hanging fog for dungeons.

To use this feature the soft particles setting must be enabled. This setting can either be activated in the OpenMW launcher or changed in settings.cfg:

[Shaders]
soft particles = true

Variables.

Name	Description	Type	Default
size	Scaling ratio. Larger values will make a softer fade effect. Larger geometry requires higher values.	integer	45
falloff	Fades away geometry as camera gets closer. Geometry full fades when parallel to camera.	boolean	false
falloffDepth	The units at which geometry starts to fade.	float	300

Example usage.

omw:data {
    "shader" : {
        "soft_effect" : {
            "size": 250,
            "falloff" : false,
            "falloffDepth": 5,
        }
    }
}

Distortion

This effect is used to imitate effects such as refraction and heat distortion. A common use case is to assign a normal map to the diffuse slot to a material and add uv scrolling. The red and green channels of the texture are used to offset the final scene texture. Blue and alpha channels are ignored.

To use this feature the post processing setting must be enabled. This setting can either be activated in the OpenMW launcher, in-game, or changed in settings.cfg:

[Post Processing]
enabled = false

Variables.

Name	Description	Type	Default
strength	The strength of the distortion effect. Scales linearly.	float	0.1

Example usage.

omw:data {
    "shader" : {
        "distortion" : {
            "strength": 0.12,
        }
    }
}