README.md

OfxJFA - OpenFrameworks Jump Flooding addon

An addon for the C++ creative coding framework OpenFrameworks of the Jump Flooding algorithm implemented with GLSL shaders. The Jump Flooding algorithm is a method of constructing Voronoi diagrams by encoding the distance and ID of the closest seed in a texture for every pixel. This addon follows the description of implementation by this article by Ryan Kaplan.

color map of jump flood output

Using ofxJFA

Using ofxJFA is as simple as passing an ofxTexture to the update() method of an instance of the ofxJFA class. The class then does 11 passes of Jump Flooding, writing the output each time to an RGBA32F texture and returns it in the end.

Declare and Init

//ofApp.h
#include "ofxJFA.h"
ofxJfa jfa;

//ofApp.cpp 
//width and height of source
jfa.init(1280,720); 

Update

//ofApp.cpp

//pass in source texture
jfa.update(sourceTexture); 

Using the output

The output of this addon is a JFA encoding, where the XY coordinates to the nearest seed is recorded in the red and green channels of the texture and the distance to it in the blue channel.

The texture can then be used in another shader for other purposes.

//ofApp.cpp

// passing the texture into another shader
shader.setUniformTexture("jfa", jfa.getTexture(), 0);
shader.setUniformTexture("src", sourceTexture(), 1);

//shader.frag

//get encoded data
vec4 loc = texture(jfa, gl_FragCoord.xy); 
//use encoded data to get color data from source
gl_FragColor = texture(src, loc.xy);