Eye

The Eye Master Stack enables you to render custom physically-based eye materials in the High Definition Render Pipeline (HDRP). It models a two-layer material, in which the first layer describes the cornea and fluids on the surface, and the second layer describes the sclera and the iris, visible through the first layer. It supports various effects, such as cornea refraction, caustics, pupil dilation, limbal darkening, and subsurface scattering.

Creating an Eye Shader Graph

To create an Eye material in Shader Graph, you can either:

Modify an existing Shader Graph.
1. Open the Shader Graph in the Shader Editor.
2. In Graph Settings, select the HDRP Target. If there isn't one, go to Active Targets, click the Plus button, and select HDRP.
3. In the Material drop-down, select Eye.
Create a new Shader Graph.
1. Go to Assets > Create > Shader Graph > HDRP and click Eye Shader Graph.

Contexts

This Master Stack material type has its own set of Graph Settings. Because of the relationship between settings and Blocks, this has consequences on which Blocks are relevant to the Graph. This section contains information on the Blocks this Master Stack material type adds by default, and which Blocks set properties for this Master Stack material type's Graph Settings.

For more information about the relationship between Graph Settings and Blocks, see Contexts and Blocks.

Vertex Context

Default

When you create a new Eye Master Stack, the Vertex Context contains the following Blocks by default:

Property	Description	Setting Dependency	Default Value
Position	The object space vertex position per vertex.	None	CoordinateSpace.Object
Normal	The object space vertex normal per vertex.	None	CoordinateSpace.Object
Tangent	The object space vertex tangent per vertex.	None	CoordinateSpace.Object

Relevant

Depending on the Graph Settings you use, Shader Graph can add the following locks to the Vertex Context:

Property	Description	Setting Dependency	Default Value
Tessellation Factor	The number of subdivisions that a triangle can have. If you want more subdivisions, set this to a higher value. More subdivisions increase the strength of the tessellation effect and further smooths the geometry. Note that higher values also increase the resource intensity of the tessellation effect. To maintain good performance on the Xbox One or PlayStation 4, do not use values greater than 15. This is because these platforms cannot consistently handle this many subdivisions. A value of 1.0 mean no tessellation.	• Tessellation enabled	1
Tessellation Displacement	The world space displacement to apply to the world position of mesh vertices after the tessellation process. It is recommended to displace along the world space normal with a displacement map, the displacement map must be sample with a Sample Texture 2D LOD, regular Sample Texture 2D isn't supported.	• Tessellation enabled	CoordinateSpace.World

Fragment Context

Default

When you create a new Eye Master Stack, the Fragment Context contains the following Blocks by default:

Property	Description	Setting Dependency	Default Value
Base Color	The base color of the material.	None	Color.grey
Normal Tangent Space	The normal, in tangent space, for the material.	• Fragment Normal Space set to Tangent	CoordinateSpace.Tangent
Bent Normal	The bent normal of the fragment. HDRP uses bent normal maps to simulate more accurate ambient occlusion. Bent normals only work with diffuse lighting.	• Material set to Eye, Fabric, Hair, Lit, or StackLit	CoordinateSpace.Tangent
Smoothness	The material's smoothness. Every light ray that hits a smooth surface bounces off at predictable and consistent angles. For a perfectly smooth surface that reflects light like a mirror, set this to a value of 1. Less smooth surfaces reflect light over a wider range of angles (because the light hits the bumps in the microsurface), so the reflections have less detail and spread across the surface in a more diffused pattern.	None	0.5
IOR	The index of refraction for this Material. The index of refraction defines the ratio between the speed of light in a vacuum and the speed of light in the medium of the Material. Higher values produce more intense refraction.	• Material Type set to Eye	1.4
Ambient Occlusion	The material's ambient occlusion. This approximates occlusion for a fragment on a GameObject’s surface that has been cast by details present in the Material but not the mesh geometry. A value of 0 means the fragment is completely occluded and appears black. A value of 1 means the fragment is not occluded at all, and the ambient color does not change.	None	1.0
Mask	Specifies whether the current fragment represents the iris or the sclera. The Shader Graph only uses the x component of this Vector2. A value of 0 means the fragment represents the sclera, and a value of 1 means the fragment represents the iris. A value between 0 and 1 results in a linear blend between sclera and iris.	• Material set to Eye	Vector2(1.0, 0)
Emission	The color of light to emit from this material's surface. Emissive materials appear as a source of light in your scene.	None	Color.black
Alpha	The Material's alpha value. This determines how transparent the material is. The expected range is 0 - 1.	None	1.0

Relevant

Depending on the Graph Settings you use, Shader Graph can add the following Blocks to the Fragment Context:

Property	Description	Setting Dependency	Default Value
Alpha Clip Threshold	The alpha value limit that HDRP uses to determine whether to render each pixel. If the alpha value of the pixel is equal to or higher than the limit, HDRP renders the pixel. If the value is lower than the limit, HDRP does not render the pixel. The default value is 0.5.	• Alpha Clipping enabled	0.5
Alpha Clip Threshold Depth Postpass	The alpha value limit that HDRP uses for the transparent depth postpass. If the alpha value of the pixel is equal to or higher than this limit, HDRP renders the pixel. If the value is lower than the limit, HDRP does not render the pixel. The default value is 0.5.	• Alpha Clipping enabled • Transparent Depth Postpass enabled	0.5
Alpha Clip Threshold Depth Prepass	The alpha value limit that HDRP uses for the transparent depth prepass. If the alpha value of the pixel is equal to or higher than this limit, HDRP renders the pixel. If the value is lower than the limit, HDRP does not render the pixel. The default value is 0.5.	• Alpha Clipping enabled • Transparent Depth Prepass enabled	0.5
Alpha Clip Threshold Shadow	The alpha value limit that HDRP uses to determine whether it should render shadows for a pixel. If the alpha value of the pixel is equal to or higher than this limit, HDRP renders the pixel. If the value is lower than the limit, HDRP does not render the pixel. The default value is 0.5.	• Use Shadow Threshold enabled	0.5
Baked Back GI	The global illumination (GI) value to apply to the back face of the Mesh only. This replaces the built-in diffuse GI solution. This port only appears when you enable the Override Baked GI setting.	• Override Baked GI enabled	0.0
Baked GI	The global illumination (GI) value to apply to the front face of the Mesh only. This replaces the built-in diffuse GI solution.	• Override Baked GI enabled	0.0
Depth Offset	The value that the Shader uses to increase the depth of the fragment by. This Block requires you to input the result of the Parallax Occlusion Mapping Node to produce a realistic result.	• Depth Offset enabled	0.0
Diffusion Profile	The Diffusion Profile to use for subsurface scattering and transmission.	• Material Type set to Subsurface Scattering or Translucent	0.0
Iris Normal Object Space	The normal of the eye's iris in object space.	• Material Type set to Eye • Iris Normal enabled • Fragment Normal Space set to Object	CoordinateSpace.Object
Iris Normal Tangent Space	The normal of the eye's iris in tangent space.	• Material Type set to Eye • Iris Normal enabled • Fragment Normal Space set to Tangent	CoordinateSpace.Tangent
Iris Normal World Space	The normal of the eye's iris in world space.	• Material Type set to Eye • Iris Normal enabled • Fragment Normal Space set to World	CoordinateSpace.World
Normal Object Space	The normal, in object space, for the material.	• Fragment Normal Space set to Object	CoordinateSpace.Object
Normal World Space	The normal, in world space, for the material.	• Fragment Normal Space set to World	CoordinateSpace.World
Specular AA Screen Space Variance	The strength of the geometric specular anti-aliasing effect between 0 and 1. Higher values produce a blurrier result with less aliasing.	• Specular AA enabled	0.0
Specular AA Threshold	The maximum value that HDRP subtracts from the smoothness value to reduce artifacts.	• Specular AA enabled	0.0
Specular Occlusion	A multiplier for the intensity of specular global illumination.	• Specular Occlusion Mode set to Custom	1.0
Subsurface Mask	The strength of the screen-space blur effect across the Material.	• Material set to Lit • Material Type set to Subsurface Scattering.	1.0

Graph Settings

Surface Options

Property	Description
Material Type	Specifies the method HDRP uses to calculate caustics in the eye's iris. Currently, the quality difference between the two methods is marginal and the best one for your project depends on the context. The options are: • Eye: A low resource-intensity caustic calculation method. • Eye Cinematic: Produces a more realistic caustic effect. This is the same caustic calculation algorithm as used in The Heretic. This method is more resource-intensive than Eye.
Recursive Rendering	Indicates whether to include this material in the recursive rendering pipeline. When enabled, if your project supports ray tracing and a Recursive Rendering Volume Profile override is active, HDRP uses ray tracing to render this material.
Surface Type	Specifies whether the material supports transparency or not. Materials with a Transparent Surface Type are more resource intensive to render than Materials with an Opaque Surface Type. Depending on the option you select, HDRP exposes more properties. The options are: • Opaque: • Transparent: Simulates a translucent Material that light can penetrate, such as clear plastic or glass. For more information about the feature and for the list of properties each Surface Type exposes, see the Surface Type documentation.
- Rendering Pass	Specifies the rendering pass that HDRP processes this material in. • Before Refraction: Draws the GameObject before the refraction pass. This means that HDRP includes this Material when it processes refraction. To expose this option, select Transparent from the Surface Type drop-down. • Default: Draws the GameObject in the default opaque or transparent rendering pass pass, depending on the Surface Type. • Low Resolution: Draws the GameObject in half resolution after the Default pass. • After post-process: For Unlit Materials only. Draws the GameObject after all post-processing effects.
- Blending Mode	Specifies the method HDRP uses to blend the color of each pixel of the material with the background pixels. The options are: • Alpha: Uses the Material’s alpha value to change how transparent an object is. 0 is fully transparent. 1 appears fully opaque, but the Material is still rendered during the Transparent render pass. This is useful for visuals that you want to be fully visible but to also fade over time, like clouds. • Additive: Adds the Material’s RGB values to the background color. The alpha channel of the Material modulates the intensity. A value of 0 adds nothing and a value of 1 adds 100% of the Material color to the background color. • Premultiply: Assumes that you have already multiplied the RGB values of the Material by the alpha channel. This gives better results than Alpha blending when filtering images or composing different layers. This property only appears if you set Surface Type to Transparent.
- Receive Fog	Indicates whether fog affects the transparent surface. When disabled, HDRP does not take this material into account when it calculates the fog in the Scene.
- Depth Test	Specifies the comparison function HDRP uses for the depth test.
- Depth Write	Indicates whether HDRP writes depth values for GameObjects that use this material.
- Cull Mode	Specifies the face to cull for GameObjects that use this material. The options are: • Front: Culls the front face of the mesh. • Back: Culls the back face of the mesh. This property only appears if you disable Double Sided.
- Sorting Priority	Allows you to change the rendering order of overlaid transparent surfaces. For more information and an example of usage, see the Material sorting documentation. This property only appears if you set Surface Type to Transparent.
- Back Then Front Rendering	Indicates whether HDRP renders this material in two separate draw calls. HDRP renders the back face in the first draw call and the front face in the second. This property only appears if you set Surface Type to Transparent.
- Transparent Depth Prepass	Indicates whether HDRP adds polygons from the transparent surface to the depth buffer to improve their sorting. HDRP performs this operation before the lighting pass and this process improves GPU performance.
- Transparent Depth Postpass	Indicates whether HDRP adds polygons to the depth buffer that post-processing uses. HDRP performs this operation before the lighting pass. Enabling this feature is useful if you want to use post-processing effects that use depth information, like motion blur or depth of field.
- Transparent Writes Motion Vectors	Indicates whether HDRP writes motion vectors for transparent GameObjects that use this Material. This allows HDRP to process effects like motion blur for transparent objects. For more information on motion vectors, see the motion vectors documentation. This property only appears if you set Surface Type to Transparent.
- - Preserve Specular Lighting	Indicates whether to make alpha blending not reduce the intensity of specular highlights. This preserves the specular elements on the transparent surface, such as sunbeams shining off glass or water. This property only appears if you set Surface Type to Transparent.
Alpha Clipping	Indicates whether this material acts like a Cutout Shader. For more information about the feature and for the list of properties this feature exposes, see the Alpha Clipping documentation.
- Use Shadow Threshold	Indicates whether HDRP uses another threshold value for alpha clipping shadows. This property only appears if you enable Alpha Clipping.
- Alpha to Mask	Indicates whether to turn on alpha-to-coverage. If your Project uses MSAA, alpha-to-coverage modifies the multi-sample coverage mask proportionally to the pixel shader result alpha value. This is typically used for anti-aliasing vegetation and other alpha-tested shaders. This property only appears if you enable Alpha Clipping.
Double Sided Mode	Specifies how HDRP renders the faces of polygons in the mesh geometry. The options are: • Disabled: Only renders one face of the polygons. • Enabled: Renders both faces of the polygons. In this mode, the normal of the back face is the same as the front face. • Flipped Normals: Renders both faces of the polygons. In this mode, the normal of the back face is 180° of the front-facing normal. This also applies to the material, which means that it looks the same on both sides of the geometry. • Mirrored Normals: Renders both faces of the polygons. In this mode, the normal of the back face mirrors the front-facing normal. This also applies to the material, which means that it inverts on the back face. This is useful when you want to keep the same shape on both sides of the geometry, for example, for leaves. For more information about this feature, see Double-sided.
Fragment Normal Space	Specifies the normal map space that this Material uses. • TangentSpace: Defines the normals in tangent space. Use this to tile a Texture on a Mesh. • ObjectSpace: Defines the normals in object space. Use this for planar-mapping GameObjects like the terrain. • WorldSpace: Defines the normal maps in world space.
Receive Decals	Indicates whether HDRP can draw decals on this material’s surface.
Receive SSR/SSGI	Indicates whether HDRP includes this material when it processes the screen space reflection pass. HDRP also takes this material into account when it calculates screen space global illumination. This property only appears if you set Surface Type to Opaque.
Receive SSR Transparent	Indicates whether HDRP includes this material when it processes the screen space reflection pass. This property only appears if you set Surface Type to Transparent.
Geometric Specular AA	Indicates whether HDRP performs geometric anti-aliasing on this material. This modifies the smoothness values on the surfaces of curved geometry to remove specular artifacts. For more information about the feature and for the list of properties this feature exposes, see the Geometric Specular Anti-aliasing documentation.
Depth Offset	Indicates whether HDRP modifies the depth buffer according to the displacement. This allows effects that use the depth buffer (Contact Shadows for example) to capture pixel displacement details.
- Conservative	Indicates whether HDRP only applies positive depth offsets in order to take advantage of the early depth test mechanic.
Add Custom Velocity	Indicates whether HDRP changes the motion vector according to the provided velocity. HDRP adds the provided velocity (the difference between the current frame position and the last frame position) to the motion vector calculation. This provides correct motion vector calculations for any procedural geometry that HDRP calculates outside of Shader Graph. The motion vector still takes into account other deformations (for example, skinning or vertex animation).
Tessellation	Tessellation Shaders subdivide the Mesh and add vertices according to the Material’s tessellation options, see the Tessellation documentation.
Subsurface Scattering	Indicates whether the Material supports subsurface scattering. To disable subsurface scattering in specific regions of the Material, use the Subsurface Mask.
Iris Normal	Indicates whether to use custom normals for the iris. When enabled, the Iris Normal Block sets the normal of the iris for the current fragment. When disabled, it uses the Normal Block.

Advanced Options

Property	Description
Specular Occlusion Mode	The mode that HDRP uses to calculate specular occlusion. The options are: • Off: Disables specular occlusion. • From AO: Calculates specular occlusion from the ambient occlusion map and the Camera's view vector. • From AO and Bent Normal: Calculates specular occlusion from the ambient occlusion map, the bent normal map, and the Camera's view vector. • Custom: Allows you to specify your own specular occlusion values.
Override Baked GI	Indicates whether this Material ignores global illumination (GI) in the Scene and instead uses custom GI values. Enable this setting to add two baked GI Blocks to the Fragment Context that control GI for the Material. Disable this setting to make the Material use the Scene's GI.
Support Lod Crossfade	Indicates whether HDRP processes dithering when a mesh moves moves from one LOD level to another.
Add Precomputed Velocity	Indicates whether to use precomputed velocity information stored in an Alembic file.

Other top level settings

Property	Description
Support VFX Graph	Indicates whether this Shader Graph supports the Visual Effect Graph. If you enable this property, output contexts can use this Shader Graph to render particles. The internal setup that Shader Graph does to support visual effects happens when Unity imports the Shader Graph. This means that if you enable this property, but don't use the Shader Graph in a visual effect, there is no impact on performance. It only affects the Shader Graph import time.

Property

Description

Support VFX Graph

Indicates whether this Shader Graph supports the Visual Effect Graph. If you enable this property, output contexts can use this Shader Graph to render particles. The internal setup that Shader Graph does to support visual effects happens when Unity imports the Shader Graph. This means that if you enable this property, but don't use the Shader Graph in a visual effect, there is no impact on performance. It only affects the Shader Graph import time.