It’s Just Data!The Wonderful World of Shaders

Daniel S. Buckstein

VT Game Developers Meetup

Feb. 22, 2018

Daniel S. Buckstein

Hello World

Dan “ShaderMan” Buckstein

Assistant Professor, Champlain

College (Game Programming)

– M.Sc, Computer Science, UOIT

– B.IT, Game Development & Entrepreneurship, UOIT

– Favourite games: Dragon Quest I-VI, Super Mario 64, Banjo-Kazooie

Daniel S. Buckstein

What are we talking about?

• The technical yet cross-discipline perspective.

• Not really shaders for Unity, Unreal, Maya...

1. “It’s just data!”

2. Shaders are for everyone

3. Tricks of the trade

Daniel S. Buckstein

How much is there to discuss?

• This talk:

45-ish minutes

• Graphics curriculum in EGP at Champlain:

90 – 135 cr. hoursDaniel S. Buckstein

My First Shader

• CircaFeb. 20-something, 2011

• I was bored.

Daniel S. Buckstein

What are shaders?

Daniel S. Buckstein

https://www.lri.fr/~mbl/ENS/IG2/docs/opengl-stm.pdf

What are shaders?

• Shaders are the “programmable” in “programmable pipeline”

Daniel S. Buckstein

http://www.3dgep.com/wp-content/uploads/2014/02/OpenGL-4.0-Pipeline.png

Data input/output (API/framebuffer)OpenGL-controlled process

Shader: programmer-controlled process

Don’t forget me…

What are shaders?

• Shaders are the “programmable” in “programmable pipeline”

• A chain of shaders is called a shader program

– E.g. VS TCS TES GS FS

– E.g. VS GS FS

– E.g. VS FS (most popular)

– E.g. VS (minimum requirement)

– E.g. CS (must be standalone)

Daniel S. Buckstein

What are shaders?

• Well-known shading languages:

• Cg: C for graphics (Nvidia) rip

• HLSL: High-Level Shading Language (v6.0)

• GLSL: The OpenGL Shading Language (v4.6)

• Metal: Apple’s proprietary language (v2.0)

• SPIR-V: Vulkan’s core language (v1.0)

Daniel S. Buckstein

Daniel S. Buckstein

The one rule to rule them all:

It’s just

data!Daniel S. Buckstein

It’s just data!

• A shader program eats raw data:

• API defines geometry, stores it in vertex buffer

• Vertex shader reads this only as you tell it to!

Daniel S. Buckstein

Data in interleaved VBO:

𝑝0𝑥 𝑝0𝑦 𝑝0𝑧 ො𝑛0𝑥 ො𝑛0𝑦 ො𝑛0𝑧 𝑢0 𝑣0 𝑝1𝑥 𝑝1𝑦 𝑝1𝑧 ො𝑛1𝑥 ො𝑛1𝑦 ො𝑛1𝑧 𝑢1 𝑣1

“position” “normal” “texcoord”

The first vertex (all of it!) The second vertex…

It’s just data!

• A shader program also outputs raw data:

Off-screen render pass(assume same size as display)

DepthBACK BUFFER (main target)

Daniel S. Buckstein

It’s just data!

• Shaders are fancy data readers and writers.

• They are crazy fast.

• And they don’t give a damn.

Daniel S. Buckstein

What can shaders do?

• The misnomer: a shader does not “shade”

• Its true purpose is to manipulate data

Vertex shader Vertices (mesh data)

Tessellation Mesh detail (LOD)

Geometry Primitives (multiple VS)

Fragment Framebuffer (“color”)

Compute Whatever you want

Daniel S. Buckstein

What can shaders do?

• Sprite sheet animation vertex shader

• Mesh deformation vertex shader

• Particles geometry shader

• Stereo 3D/VR parallel geometry shader

• Any and all shading fragment shader

• Post-processing fragment shader

• Anything and everything compute shader

Daniel S. Buckstein

What can shaders do?

• Compute is easier than it sounds…

Daniel S. BucksteinCourtesy of Michael G.

Who cares about shaders?

• Programmer: build the framework, feed data

• Artist: manipulate data to make pretty things

• Designer: high-level code… you can code too!

• Producer: graphics player $$$$$

• Other: simulation… film… stage… audio…

Daniel S. Buckstein

Who cares about shaders?

• Engines and editors (e.g. Unity, Unreal, Maya) write the shader programs for you…

• …anyone can define the “materials”:

Daniel S. Buckstein

How do we manipulate data?

• Why should I tell you…

Daniel S. Buckstein

…when I can show you?

Conclusion

• What does my future hold???

• What does your future hold???

Better graphics.

Better games.

Daniel S. Buckstein

Conclusion

• Where can you get started?

• www.kickjs.org VS & FS

• www.shadertoy.com only FS

• Check out some other people’s work: • Pac-Man: https://www.shadertoy.com/view/Ms3XWN

• Doom: https://www.shadertoy.com/view/lldGDr

• Others: https://shadertoyunofficial.wordpress.com/2017/11/11/playable-games-in-shadertoy/

Daniel S. Buckstein

Conclusion

• Where can you get started?

• Learn some math.

• Read a book.

• Just do it.

Daniel S. Buckstein

Vectors, matrices, quaternions.

OpenGL SuperBible, Real-Time Rendering

Conclusion

• It’s just data…

• Communication with the GPU is key.

• Get busy, there’s so much to do!

Daniel S. Buckstein

The end.

• Questions? Comments? Concerns?

Daniel S. Buckstein