Triplanar Node

Description

Triplanar is a method of generating UVs and sampling a texture by projecting in world space. The input Texture is sampled 3 times, once in each of the world x, y and z axes, and the resulting information is planar projected onto the model, blended by the normal, or surface angle. The generated UVs can be scaled with the input Tile and the final blending strength can be controlled with the input Blend. Blend controls the way the normal affects the blending of each plane sample and should be greater or equal to 0. The larger blend is, the more contribution will be given to the sample from the plane towards which the normal is most oriented. (The maximum blend exponent is between 17 and 158 depending on platform and the precision of the node.) A blend of 0 makes each plane get equal weight regardless of normal orientation. The projection can be modified by overriding the inputs Position and Normal. This is commonly used to texture large models such as terrain, where hand authoring UV coordinates would be problematic or not performant.

The expected type of the input Texture can be switched with the dropdown Type. If set to Normal the normals will be converted into world space so new tangents can be constructed then converted back to tangent space before output.

If you experience texture sampling errors while using this node in a graph which includes Custom Function Nodes or Sub Graphs, you can resolve them by upgrading to version 10.3 or later.

NOTE: This Node can only be used in the Fragment shader stage.

Ports

Name	Direction	Type	Binding	Description
Texture	Input	Texture	None	Input texture value
Sampler	Input	Sampler State	None	Sampler for input Texture
Position	Input	Vector 3	World Space Position	Fragment position
Normal	Input	Vector 3	World Space Normal	Fragment normal
Tile	Input	Float	None	Tiling amount for generated UVs
Blend	Input	Float	None	Blend factor between different samples
Out	Output	Vector 4	None	Output value

Controls

Name	Type	Options	Description
Type	Dropdown	Default, Normal	Type of input Texture

Generated Code Example

The following example code represents one possible outcome of this node.

Default

float3 Node_UV = Position * Tile;
float3 Node_Blend = pow(abs(Normal), Blend);
Node_Blend /= dot(Node_Blend, 1.0);
float4 Node_X = SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.zy);
float4 Node_Y = SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.xz);
float4 Node_Z = SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.xy);
float4 Out = Node_X * Node_Blend.x + Node_Y * Node_Blend.y + Node_Z * Node_Blend.z;

Normal

float3 Node_UV = Position * Tile;
float3 Node_Blend = max(pow(abs(Normal), Blend), 0);
Node_Blend /= (Node_Blend.x + Node_Blend.y + Node_Blend.z ).xxx;
float3 Node_X = UnpackNormal(SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.zy));
float3 Node_Y = UnpackNormal(SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.xz));
float3 Node_Z = UnpackNormal(SAMPLE_TEXTURE2D(Texture, Sampler, Node_UV.xy));
Node_X = float3(Node_X.xy + Normal.zy, abs(Node_X.z) * Normal.x);
Node_Y = float3(Node_Y.xy + Normal.xz, abs(Node_Y.z) * Normal.y);
Node_Z = float3(Node_Z.xy + Normal.xy, abs(Node_Z.z) * Normal.z);
float4 Out = float4(normalize(Node_X.zyx * Node_Blend.x + Node_Y.xzy * Node_Blend.y + Node_Z.xyz * Node_Blend.z), 1);
float3x3 Node_Transform = float3x3(IN.WorldSpaceTangent, IN.WorldSpaceBiTangent, IN.WorldSpaceNormal);
Out.rgb = TransformWorldToTangent(Out.rgb, Node_Transform);