UnityGame/Library/PackageCache/com.unity.shadergraph/Documentation~/Parallax-Occlusion-Mapping-Node.md

Parallax Occlusion Mapping Node

Description

You can use the Parallax Occlusion Mapping (POM) node to create a parallax effect that displaces a material's UVs and depth to create the illusion of depth inside that material.

If you receive a texture sampling error while using this node in a graph that includes Custom Function nodes or Subgraphs, try upgrading to Shader Graph version 10.3 or later. This may resolve the errors.

When you assign the same Texture2D to a POM node and a Sample Texture 2D node, you need to avoid transforming the UV coordinates twice. To prevent this, connect the Split Texture Transform node’s Texture Only port to the Sample Texture 2D Node’s UV port.

Ports

Name	Direction	Type	Description
Heightmap	Input	Texture2D	The Texture that specifies the depth of the displacement.
Heightmap Sampler	Input	Sampler State	The Sampler to sample Heightmap with.
Amplitude	Input	Float	A multiplier to apply to the height of the Heightmap (in centimeters).
Steps	Input	Float	The number of steps that the linear search of the algorithm performs.
UVs	Input	Vector2	The UVs that the sampler uses to sample the Texture.
Tiling	Input	Vector2	The tiling to apply to the input UVs.
Offset	Input	Vector2	The offset to apply to the input UVs.
Primitive Size	Input	Vector2	Size of the UV space in object space. For example, a Unity built-in Plane mesh has a primitive size of (10,10).
LOD	Input	Float	The level of detail to use to sample the Heightmap. This value should always be positive.
LOD Threshold	Input	Float	The Heightmap mip level where the Parallax Occlusion Mapping effect begins to fade out. This is equivalent to the Fading Mip Level Start property in the High Definition Render Pipeline's (HDRP) Lit Material.
Pixel Depth Offset	Output	Float	The offset to apply to the depth buffer to produce the illusion of depth. Connect this output to the Depth Offset on the Master Node to enable effects that rely on the depth buffer, such as shadows and screen space ambient occlusion.
Parallax UVs	Output	Vector2	UVs that you have added the parallax offset to.

Generated Code Example

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

float3 ParallaxOcclusionMapping_ViewDir = IN.TangentSpaceViewDirection * GetDisplacementObjectScale().xzy;
float ParallaxOcclusionMapping_NdotV = ParallaxOcclusionMapping_ViewDir.z;
float ParallaxOcclusionMapping_MaxHeight = Amplitude * 0.01;
ParallaxOcclusionMapping_MaxHeight *= 2.0 / ( abs(Tiling.x) + abs(Tiling.y) );

float2 ParallaxOcclusionMapping_UVSpaceScale = ParallaxOcclusionMapping_MaxHeight * Tiling / PrimitiveSize;

// Transform the view vector into the UV space.
float3 ParallaxOcclusionMapping_ViewDirUV    = normalize(float3(ParallaxOcclusionMapping_ViewDir.xy * ParallaxOcclusionMapping_UVSpaceScale, ParallaxOcclusionMapping_ViewDir.z)); // TODO: skip normalize

PerPixelHeightDisplacementParam ParallaxOcclusionMapping_POM;
ParallaxOcclusionMapping_POM.uv = UVs.xy;

float ParallaxOcclusionMapping_OutHeight;
float2 _ParallaxOcclusionMapping_ParallaxUVs = UVs.xy + ParallaxOcclusionMapping(Lod, Lod_Threshold, Steps, ParallaxOcclusionMapping_ViewDirUV, ParallaxOcclusionMapping_POM, ParallaxOcclusionMapping_OutHeight);

float _ParallaxOcclusionMapping_PixelDepthOffset = (ParallaxOcclusionMapping_MaxHeight - ParallaxOcclusionMapping_OutHeight * ParallaxOcclusionMapping_MaxHeight) / max(ParallaxOcclusionMapping_NdotV, 0.0001);