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2. GenerativeArt–MadewithUnity
Best Practices for
Shader Graph
2
Charles Sanglimsuwan
Developer Relations Engineer

3. What we'll cover today
 Motivations
 Demo
 How Shader Graph works
 Choosing the right Master Node
 Optimizations
 Workflow
 What’s next
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4. Motivations
4

5. 5
Democratize
Development
Solve Hard
Problems
Enable
Success

6. 6

7. Brief History
 Early work started in May 2017
 Preview package released in Unity 2018.1
 23 updates since
7

8. How Shader Graph works
8

9. Scriptable Render Pipeline
 Shader Graph requires SRP
 High Definition Render Pipeline (HDRP)
 Lightweight Render Pipeline (LWRP)
 VR Lightweight Render Pipeline (VR LWRP)
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10. The Master Node
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11. Shader Generation Process
 Each Render Pipeline has a shader backend
 Shader backends include subshader generators for supported Master
Nodes
 Not all Master Nodes supported by every RP
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12. Subshader Generators
 Each Master Node has a per-pipeline template
 Templates have many injection points
 Your Shader Graph is traversed, and injection points are replaced with
node values
 Final outcome is a shader (written in ShaderLab)
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13. Shader Anatomy
13

14. Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
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Shader Graph

15. 15
Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
Shader Graph

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Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
Shader Graph

17. 17
Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
Shader Graph

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void Unity_Multiply_float (float3 A, float3 B, out float3 Out)
{
Out = A * B;
}
struct SurfaceDescriptionInputs
{
float3 WorldSpaceTangent;
}
struct SurfaceDescription
{
float3 Albedo;
}
SurfaceDescription PopulateSurfaceData (SurfaceDescriptionInputs IN)
{
SurfaceDescription surface = (SurfaceDescription)0;
float _Vector1_1EF2E600_Out = 2;
float3 _Multiply_E1E37A64_Out;
Unity_Multiply_float(IN.WorldSpaceTangent,
_Vector1_1EF2E600_Out.xxx,
_Multiply_E1E37A64_Out)
surface.Albedo = _Multiply_E1E37A64_Out;
return surface;
}
Example: Surface Description

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void Unity_Multiply_float (float3 A, float3 B, out float3 Out)
{
Out = A * B;
}
struct SurfaceDescriptionInputs
{
float3 WorldSpaceTangent;
}
struct SurfaceDescription
{
float3 Albedo;
}
SurfaceDescription PopulateSurfaceData (SurfaceDescriptionInputs IN)
{
SurfaceDescription surface = (SurfaceDescription)0;
float _Vector1_1EF2E600_Out = 2;
float3 _Multiply_E1E37A64_Out;
Unity_Multiply_float(IN.WorldSpaceTangent,
_Vector1_1EF2E600_Out.xxx,
_Multiply_E1E37A64_Out)
surface.Albedo = _Multiply_E1E37A64_Out;
return surface;
}
Example: Surface Description

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void Unity_Multiply_float (float3 A, float3 B, out float3 Out)
{
Out = A * B;
}
struct SurfaceDescriptionInputs
{
float3 WorldSpaceTangent;
}
struct SurfaceDescription
{
float3 Albedo;
}
SurfaceDescription PopulateSurfaceData (SurfaceDescriptionInputs IN)
{
SurfaceDescription surface = (SurfaceDescription)0;
float _Vector1_1EF2E600_Out = 2;
float3 _Multiply_E1E37A64_Out;
Unity_Multiply_float(IN.WorldSpaceTangent,
_Vector1_1EF2E600_Out.xxx,
_Multiply_E1E37A64_Out)
surface.Albedo = _Multiply_E1E37A64_Out;
return surface;
}
Example: Surface Description

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void Unity_Multiply_float (float3 A, float3 B, out float3 Out)
{
Out = A * B;
}
struct SurfaceDescriptionInputs
{
float3 WorldSpaceTangent;
}
struct SurfaceDescription
{
float3 Albedo;
}
SurfaceDescription PopulateSurfaceData (SurfaceDescriptionInputs IN)
{
SurfaceDescription surface = (SurfaceDescription)0;
float _Vector1_1EF2E600_Out = 2;
float3 _Multiply_E1E37A64_Out;
Unity_Multiply_float(IN.WorldSpaceTangent,
_Vector1_1EF2E600_Out.xxx,
_Multiply_E1E37A64_Out)
surface.Albedo = _Multiply_E1E37A64_Out;
return surface;
}
Example: Surface Description

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Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
Shader Graph

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Properties
Subshader
{
Tags
Pass
{
Material Options
Includes & Defines
Graph Functions
Surface Description Input Struct
Surface Description Output Struct
Surface Description Function
Vertex Input Struct
Vertex Output Struct
Vertex Shader
Fragment Shader
}
}
Shader Graph

24. Choosing a Master Node
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25. Master Node Overview
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UnlitHD Lit PBR

26. PBR Master Node
 Works with all Render Pipelines
 Good starting point for prototyping
 Feature ready for many scenarios
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27. HD Lit Master Node
 Compatible only with HDRP
 More features than PBR
 Easy to add needless complexity
27

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29. Unlit Master Node
 Works with all Render Pipelines
 Very lightweight
 Good for effects, vertex modifications
29

30. Unlit Master Node
Possible to add custom lighting:
1. Create nodes to calculate lighting
from desired shading model (e.g., Blinn-Phong)
2. Connect output color to the Color port
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31. Master Node Review
 PBR is the most versatile node
 Use HD Lit only when applicable and necessary
 Consider Unlit for particle effects, UI, etc.
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32. Unity Optimizations
32

33. Built-in Optimizations
1. Where ever possible, Shader Graph will not add unused features to
output shader
 Changing the default value will mark the feature active
 Connecting any node will mark the feature active
2. The shader compiler will compile out no-op features
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34. Optimization Example: Coat Mask
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No CoatMask code will be present in the output
ShaderLab code if the value is zero

35. Optimization Example: Metallic
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If the Metallic is set to zero, that code block will
be compiled out by the shader compiler

36. Optimization Example: Emission
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If the Emission is set to Black, and disabled in
Material, that code block will be compiled out by
the shader compiler

37. Built-in Optimizations
1. Where ever possible, Shader Graph will not add unused features to
output shader
 Changing the default value will mark the feature active
 Connecting any node will mark the feature active
2. The shader compiler will compile out no-op features
37

38. Draw Call Batching
 GPU instancing is supported in shaders
 Needs to be enabled on the material
 Requires hardware support
 All generated shaders are compatible with the SRP Batcher (2018.3)
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39. GPU Instancing
39

40. SRP Batcher
 New batching solution, designed for SRP
 Improved rendering performance
 Works with SkinnedMeshRenderers!
 Requires per-material parameters to be stored in a constant buffer
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41. Render Faster with the SRP Batcher
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0
5
10
15
20
25
30
35
Scene: 1024 materials Scene: 1 material
RenderTime(ms)
5.26x Faster 1.27x Faster
SRP
Legacy
Lower is better

42. Graph Optimizations
42

43. Node Decimation
 Eliminate no-op nodes
 Bake values back into the textures
 Examples: gradients, noise
 Combine nodes when possible
43

44. Example: Texture Modification
44

45. Example: Power
45

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48. 48

49. Data Formats
 Each node has a memory cost
 Use smaller data structures when possible
 Modifying precision
 Requires code modification
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public enum OutputPrecision
{
@fixed,
@half,
@float
}
private OutputPrecision m_OutputPrecision = OutputPrecision.@float;
Modifying Precision
AbstractMaterialNode.cs

51. Reduce Math Operations
 Multiply scalar values before vector values
 Prefer blending results, instead of branching
 Research impact of certain math operations
 Prefer constants when possible
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52. Example: Reciprocal
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Fast mode requires Shader Model 5

53. Reduce Math Operations
 Multiply scalar values before vector values
 Prefer blending results, instead of branching
 Research impact of certain math operations
 Prefer constants when possible
53

54. Example: Properties
54

55. Workflow: Manual Optimizations
 Hand-optimizing shaders is a one-way path
 Don’t manually optimize too early
 Copy or view shader code in Master Node menu
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56. Workflow: Manual Optimizations
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57. Workflow: Faster Iterations
 Nodes not connected to Master Node aren’t evaluated
 Can keep them in view for quick iterations
 Create a Preview node that isn’t attached to the Master Node
 Editing these nodes will be much faster
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58. Workflow Summary
1. Prototype with PBR Master Node
 Move to HD Lit if necessary
2. Start optimization
1. Optimize nodes
2. Convert properties to inline values
3. Near the end of the project, start hand optimizing shaders
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59. Exploratory
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60. Custom API
 Create your own nodes
 Examples: specialized noise functions, custom lighting, etc.
 Full documentation available on GitHub
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61. Vertex Modification
 Low-impact on CPU performance
 Good for animating foliage, water, or cloth
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Foliage

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Animating Water

64. What’s next
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65. Roadmap
2019.1
 First official, verified release
 Completely overhauled Node API
 Key bug fixes, UX improvements
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66. Available Resources
 Plentiful samples abound:
 Andy Touch
 Keijiro Takahashi
 Video tutorials on YouTube
 Source available on GitHub
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67. Questions?
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Thank you