ofxSpaceColonization

This addon is an openFrameworks implementation of the paper Modeling Trees with a Space Colonization Algorithm by Adam Runions, Brendan Lane, and Przemyslaw Prusinkiewicz.

Dependecies

It requires ofxBranchesPrimitive. The example example-ofxenvelope requires the addon ofxEnvelope

Usage

//in your header file
ofxSpaceColonization tree;
// in your App.cpp file
void ofApp::setup(){
    tree.build();
}
void ofApp::update(){
    tree.grow();
}
void ofApp::draw(){
    tree.draw();
}

This will generate a tree using this standard options:

static const ofxSpaceColonizationOptions defaultSpaceColOptions = {
    150,                             // maxDist, leaves are attractive if closer than this distance
    10,                              // minDist, leaves are attractive if farther than this distance
    150,                             // trunkLength, the length of the trunk
    glm::vec4(0.0f,0.0f,0.0f, 1.0f), // rootPosition, the position of the root
    glm::vec3(0.0f, 1.0f, 0.0f),     // rootDirection, the direction on which the tree will starts to grow
    7,                               // branchLength, the length of each branch
    false,                           // doneDrawing, a value that indicates when the grow process is done
    false,                           // cap, if the cylinders that compose the branches have caps or not
    2.0,                             // radius, the radius of the branch
    16,                              // resolution, the resolution of the cylinders that compose the geometry
    1,                               // textureRepeat, how many times a texture has to be repeated on a branch
    0.9997                           // radiusScale, how much the radius will increase or decrease at each interaction
};

You can specify yours options using the setup method:

void ofApp::setup(){
    auto myOpt = ofxSpaceColonizationOptions({
       // ...
    });
    tree.setup(myOpt);
    tree.build();
}

The form of the tree changes depending on these options and on the position of the leaves. By default, some default leaves are provided but you can provide your leaves by using the setLeavesPositions() method. It takes a vector<glm::vec3> as argument.

void ofApp::setup(){
    vector<glm::vec3> points;
    // ... fullfill the vector
    tree.setLeavesPositions(points);
    tree.build();
}

I’ve created an addon that can be used to generate the points, it is called ofxEnvelope and you can see in the example example-ofxenvelope how to use it.

Wind

The grow method takes a glm::vec3 as optional parameter. This vector can be used to move the leaves, like this
Example:

void ofApp::update(){
  float t = ofGetElapsedTimef();
  float n = ofSignedNoise(t * windFreq) * windAmpl;
  auto wind = glm::vec3(n,0.0,0.0); // a weird wind that only breezes on the x axis
  tree.grow(wind);
}

Examples

example-3d

example-ofxenvelope

License

MIT

References

Procedurally Generated Trees with Space Colonization Algorithm in XNA C#

Daniel Shiffman Video

space-colonization