An Introduction toWriting Custom Unity Shaders!

Andy Touch@andytouch

Content EvangelistEurope, Middle East, Africa & Russia

Shaders

Shaders

“Shaders Are Scary!!”

Before This Talk:“WTF is a Shader? Some sort of wizardry?!”

After This Talk:“Ah, I get it now! I want to experiment!”

Wikipedia on Shaders“A Program That Tells A Computer

To Draw Something In A Specific and Unique Way”

Wow! Wikipedia got it right! :O

But why learn Shader Programming?!Built-In Shaders are for ‘generic’ use-

casesUnique and Custom Visuals!

You can do some Really Weird Stuff.Optimization!

Shader Skills are ‘Gold Dust’They aren’t THAT scary

They are fun to play with. :)

Unity Shaders Written using NVidia’s CG

But wrapped in Unity’s ShaderLab!

ShaderLab

ShaderLab

CG

ExampleShader.shader

Vertex And Fragment ShadersSurface Shader

Vertex And Fragment Shaders Surface Shader

Vertex And Fragment ShadersSurface Shader

Shader FlowStep 1) Gather the Information to Use

Shader FlowStep 2) Vertex Function (Build the Object in the World)

Shader FlowStep 3) Vertex to Fragment (Send it to the screen!)

Shader FlowStep 4) Fragment Function (Color in it’s screen pixels!)

Shader FlowStep 5) Done! Object is rendered. :)

Shader FlowStep 1) Gather the Information to Use

Shader FlowStep 2) Vertex Function (Build the Object in the World)

Shader FlowStep 3) Vertex to Fragment (Send it to the screen!)

Shader FlowStep 4) Fragment Function (Color in it’s screen pixels!)

Shader FlowStep 5) Done! Object is rendered. :)

Vertex And Fragment Shader Flow

Object Data Custom Data

Vertex Function V2F Struct Fragment Function

Object Drawn On Screen!

Shad

er

Demo Time!(Because PowerPoint is boring…)

Vertex And Fragment ShaderSurface Shader

Surface Shaders do lots Automagically

Object Lighting (Directional, Point etc)Shadows

Ambient LightingReflections

LightmappingPBR Workflow

Final Drawing to the ScreenSurface Vertex/Fragment

Default Surface V/F: Texture + Reflections

Default Surface V/F: 1 Light and Shadows

Default Surface V/F: Simple Lightmapping

Default Surface V/F Combined…

Surface Shaders do lots Automagically

But this makes them Overkill!

NO for Mobile/Low-EndSometimes tricky to manipulate

Kind-of Unity specific…“Do you need all those PBR outputs?”

BUT…They make Custom Lighting creation easier!

Color Ramp

Demo Time!(Because PowerPoint is boring…)

Diffuse Light = dot(Normal, LightDirection)

Diffuse Light = dot(Normal, LightDirection)

So… What Now?Shader Documentation

docs.unity3d.com/Manual/SL-Reference.html

So… What Now?Built-In Unity Shader Package:

unity3d.com/get-unity/download/archive

So… What Now?

Nvidia’s CG Documentationdeveloper.nvidia.com/Cg

So… What Now?

Unity CommunityAsset StoreUnify Wiki

Unity Forums (Shaders)Community Blogs

So… What Now?Google search:

“[insert game name] rendering techniques”

GDC TalksSiggraph Papers

Dev Blogs…More!

So… What Now?

Go and Experiment!It’s the best way to learn. :)

Thank You!

Andy Touch

@andytouchandyt@unity3d.com

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Samples