Displacement Shader
Overview[edit]
The Displacement shader displaces a surface by the values from any shader or function nodes assigned to its function input. Values from the assigned shader or function nodes are converted to scalar data.
Settings:
- Name: This setting allows you to apply a descriptive name to the node, which can be helpful when using multiple Displacement shader nodes in a project.
- Enable: When checked, the node is active and the Displacement shader will be applied to the surface. When unchecked, the node is ignored.
- Function: This setting allows you to assign shader or function nodes to use as displacement for the surface.
- Displacement direction: This popup has 5 options which allow you to choose the direction in which the displacement is applied in. Options that "(requires computed normal)" must have a Compute Terrain or Compute Normal node connected somewhere above the Surface Layer in the network to work properly. The popup has the following options
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Along vertical: Displacement happens along the normal of the underlying planet or 3D object’s geometry.
Along normal: Displacement happens along the current surface normal.
Vertical only (requires computed normal): Displacement only happens along the normal of the underlying planet or 3d object’s geometry. The displacement is scaled by the difference between the object normal and the surface normal. Displacement is reduced as the angle between the normals approaches 90°.
Lateral only (requires computed normal): Displacement only occurs in the lateral plane, that is perpendicular to the normal of the underlying object.
Lateral normalized (requires computed normal): This is the same as Lateral only but the normal is normalised, that is scaled so it has a length of 1.
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- Displacement multiplier: This multiplies the displacement values coming from the "Displacement function" input. A value of 1 leaves the incoming values unchanged. A value of 2 would make the incoming values twice as large. A value of 0.5 would make them half as large. Negative values will invert the displacement.
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A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.
A scalar is a single number. 1, 200.45, -45, -0.2 are all examples of scalar values.
A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.
Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.
