how to create a thousand lights stephen smithbower computer science undergraduate
TRANSCRIPT
How to Create a Thousand Lights
Stephen Smithbower Computer Science Undergraduate
Lighting is an Artistic Tool
- Creates mood and atmosphere
- Colours can be calming
- Useful for both realism and surrealism
or abrasive
Author: Brooks Elliot @ 3drender.com
Author: Dan Konieczka @ 3drender.com
Author: Hans Tetzloff @ 3drender.com
Author: Michal Kotek @ 3drender.com
Lighting is Complex
And is therefore slow to render..
- Each frame of video = 1/24th of a second
- Each frame takes on average 6 hours to render
Some frames take up to 90 hours!
Pixar
Authorship: Disney Pixar Studios
Real-Time Is a Bit More Restrictive
For smooth movement, the entire framemust be rendered in...
16 milliseconds(1/60th of a second, or 60 frames per second)
Don’t Be Pixar
Aesthetically plausible, not physically accurate
The Graphics Processing Unit (GPU)
- Excels at parallel tasks
- Much more processing power than the CPU
- Built specifically for real-time graphics
Forward Shading1111
Yellow Light
1111
Blue Light
Forward Shading1111
Yellow Light
Render this, GPU!
1 Draw Call
Forward Shading
1111
Blue Light
Render this, GPU!
2 Draw Calls
Forward Shading1111
Yellow Light
Render this, GPU!
3 Draw Calls
Forward Shading
1111
Blue Light
Render this, GPU!
4 Draw Calls
So What’s the Problem?
Bottleneck!
You’ve got a relay team..
GPU
Bottleneck!
CPU
Forward Rendering Scene Complexity
Most Video Games In Here
New Approach
- Don’t send redundant data
- Don’t worry about what is not in view
- Decouple Light and Geometry data
Current Complexity: # Objects x # Lights
Desired Complexity: # Objects + # Lights
Light Pre-Pass
Step 1: Encode Visible Geometry into a Texture
Depth
Normals
55
Light Pre-Pass
Step 2: Draw Lights as Spheres
Light Pre-Pass
Step 3: Render Scene Again - Modulate Lighting
x =
Comparison of Rendering Scene
Complexity
Comparison of Rendering Scene
Complexity
Comparison of Rendering Scene
Complexity
Comparison of Rendering Scene
Complexity
Rendered on a 2.4ghz dual-core processor, Geforce 8600gts video card
About $500 total, at time of purchase
Questions?
http://www.youtube.com/watch?v=MYMMgI9CDow
Acknowledgements
Dr. Ramon Lawrence
Computer Science Department