Katana Particle System

Here is a short demo of my accelerated GPU Particle System for Unity. This Particle System, when finished, should be an easy-to-use tool to handle millions of particles in real-time. Rendering and Physics are completely processed on GPU through compute shader kernels.

SCREEN SPACE RENDERING

I also made some research to be able to get fluid-like rendering. I found many techniques on the web but here is the document from Nvidia that brought me light on this subject. Based on it, I made all the rendering steps (point sprite, depth to normal, blurring, bilateral filter…). Caustics render pass isn’t done yet and I didn’t implement good physics kernels yet. Particles aren’t interacting each other but only interacting with buffered colliders from the scene.

CURRENT FEATURES

• Emitter rate and radius
• Forces and angular forces
• Size over time
• Particle Age
• Enable/Disable gravity (values from the Unity physic engine)
• Noise on velocities
• Change color over time
• Bounce and impact parameters
• Soft particles rendering
• GPU Collision Detection based on Unity colliders (bufferize scene colliders to interact with particles)
• Screen Space Rendering for Fluids (experimental)

COMING FEATURES

• Complex Mesh and Terrain Collision on GPU side
• Attract and Repel Force Areas
• All kind of Blend mode for rendering

MARCHING CUBE APPROACH

Lots of metaballs can be heavy for a CPU process. I absolutely wanted to implement a compute shader approach of it … to see what are the possibilities in Unity to get a real-time fluid effect.

The result is not bad, still heavy with a high definition lattice but it can be managed in a small area with a good FPS (120-150 here).

Isosurface and Marching Cube algorithms are not an easy subject but I found interesting articles and I ported some C++ sources (DirectX10) from Nvidia to Unity (DirectX11). Here are some links:

GDC2006
http://http.download.nvidia.com/developer/presentations/2006/gdc/2006-GDC-DX10-Practical-Metaballs.pdf

CPU approach
http://wiki.unity3d.com/index.php?title=MetaBalls

GPU Gems
https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch01.html