ofxAddons
Particle system addon with basic physics and neighbor-connection drawing, where particle integration and rendering run in GPU transform-feedback shaders.
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README
ofxParticleSet
Introduction
A simple CPU-based particle system with basic physics including some drawing inspired by Casey Reas' Software Structures.
License
ofxParticleSet is distributed under the MIT License. See the LICENSE file for further details. Just add my name somewhere along your project Steve Meyfroidt whenever possible.Dependencies
- Core openFrameworks (no external addons required)
Compatibility
Developed against OpenFrameworks v0.12+ (GL 4.1 core context on macOS).GPU Implementation
- Particle integration, lifetime decay and neighbor attraction now run entirely inside transform feedback vertex shaders.
- Spatial relationships are handled via a Morton-coded sort uploaded each frame; geometry shaders read the sorted buffers to draw connection lines.
- Per-particle data (position, velocity, spin, color, radius, lifetime) is stored in ping-pong VBOs and mirrored on the CPU for spawning and recycling.
- Example projects must request at least an OpenGL 4.1 core context so that transform feedback, geometry shaders, and texture buffer objects are available.
Usage Notes
- Supply normalized coordinates (0–1 in both axes) when calling
add()and when defining velocities; convert from pixel space in your app according to its viewport. - Call
add()from the main thread; additions are queued and uploaded before the next GPU update. - Use the parameter group to tune runtime behavior:
timeStep,velocityDamping,attractionStrength,initialVelocityScale,sortNeighborWindow,lineFadeExponent, etc.—they map directly to shader uniforms. - Strategies work as before: choose points, lines, or both. Connections automatically fade with distance and wrap around the viewport edges.