Parallax mapping plugin

1. Introduction

The ParallaxMappingMaterial plugin is a C++ implementation of the free Interior Mapping Shader available on Fab.

The final result in-engine:

2. Usage

2.1 Background nodes

2.1.1 Nine-Grid Texture

If you’re using a 9-grid texture atlas like this:

Drop an Interior Mapping UV node into your material graph.

Pin	Type	Description
Inputs
UVs	TexCoordinates	UV coordinates. Defaults to TexCoord[0].
CameraVectorWs	Vector3	Camera vector in world space. Use CameraVectorWS by default.
BoxDepth	Scalar	Depth of the virtual room.
AspectRatio	Scalar	\(\frac{Room_{Width}}{Room_{Height}}\) Defaults to 1 (a cube-shaped room).
AtlasColumns	Scalar	Number of grid columns in the atlas. Defaults to 3.
AtlasRows	Scalar	Number of grid rows in the atlas. Defaults to 3.
BackRow	Scalar	Which row contains the back wall. Top row = BackRow - 1, bottom row = BackRow + 1.
Outputs
Return value	Vector2	The parallax-shifted UVs. Connect to the UVs pin of a TextureSample node.

2.1.2 One Texture Per Cell

If your textures are split into individual files:

• CenterTop:
  
• CenterLeft:
  
• Center:
  
• CenterRight:
  
• CenterBottom:
  

Use the Atlas Composer node to merge them into a single atlas, then connect its AtlasUV with the output of the Interior Mapping UV node.

2.3 Foreground Elements

Use a Billboard Layer UV node to layer foreground elements with independent parallax.

Pin	Type	Description
Inputs
UVs	TexCoordinates	UV coordinates. Defaults to TexCoord[0].
CameraVectorWs	Vector3	Camera vector in world space. Use CameraVectorWS by default.
LayerDepth	Scalar	Controls where the layer sits in depth.
CellCol	Scalar	Which column of the cell this foreground element belongs to.
CellRow	Scalar	Which row of the cell this foreground element belongs to.
AtlasColumns	Scalar	Grid columns. Defaults to 3. Set to 1 when using individual textures.
AtlasRows	Scalar	Grid rows. Defaults to 3. Set to 1 when using individual textures.
Outputs
Pin 1	Vector2	The parallax-shifted UVs for the foreground layer.
Pin 2	Scalar	1.0 if the shifted UV stays within $[0,1]^2$; 0.0 if it falls outside the tile boundary.

Multiply the second output pin by your texture’s alpha to get the correct opacity mask.

2.4 Compositing Foreground and Background

Use a Lerp node, driven by the alpha mask computed in the foreground pipeline, to blend the layers together.

Two common compositing orderings:

• Sequential blending — lerp each foreground layer over the background in order:
  

• Flatten foreground first, then blend — combine all foreground layers together first, then lerp the result over the background:
  

Samples

Texture files: https://1drv.ms/f/c/53c607b8bea23158/IgDmN6ZhbhF_SIFqYHuihS8yAd4OvlsYO_YHI-Fe2mHs0Kk?e=DyZu2v

Sample Material: https://1drv.ms/f/c/53c607b8bea23158/IgAcOrITqqL9Rbpi2_DzZVFUAVaAHJgjyNPP6iRf4M7-bOM?e=ACCAZw

Copyable blueprint:

1. Nine-grid: https://blueprintue.com/blueprint/cwzojttp/
2. Individual texture: https://blueprintue.com/blueprint/fqkpjgb4/