openFrameworks addon to create 3D lathe objects
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README.md

README.md

ofxLathePrimitive

Build status Build Status

ofxLathePrimitive

This addon generates lathe geometries. Lathe geometries are geometries produced by rotating some points around a fixed axis, in my addon and in many other similar program, the up axis.

This addon is very close to that one that comes from THREE.js, and most of the code comes from there, but it has also some new features, as explained below

Usage example

A lathe primitive comes with its default, this minimal example is enough to have a lathe geometry in your scene.

void ofApp::setup(){
    lathe.build();
}

void ofApp::setup(){
    lathe.draw()
}

API

Public properties:

The public properties segments, phiStart, phiLength and points behave exactly as in this demo.

ofParameter<int> segments;

It defines the number of segments that will compose the rotating geometry.


ofParameter<float> phiStart;

The initial rotation angle.


ofParameter<float> phiLength;

The upper limit of the rotation. A value TWO_PI, for example, means a complete rotation on the y axis


ofParameter<bool> closed = false;

When the first part of the rotating mesh and the last part are close to each other, the mesh will be perfectly closed.


ofParameter<bool> flipNormals = false;

Depending on the order on which the points are inserted, the face of the generated polygon maybe in the inverted direction as expected. This option flip the faces.


ofParameterGroup parameters;

Contains all the parameter listed above.


vector<glm::vec2> points;

The vector containing the point that are going to be rotated around the y axis

Member methods

void setup(const vector<glm::vec2>points, const int segments, const float phiStart, const float phiLength);

Setup a new geometry defining points, segments, phiStart and phiLength.


void build();

It builds a ofMesh.


void clear();

It clears the mesh.


void setPoints(vector<glm::vec2> _points);

Set the points that are going to be rotated. Example:

ofxLathePrimitive lathe;
vector<glm::vec2> points;
for ( int i = 0; i < 12; i ++ ) {
    points.push_back( glm::vec2( sin( i * 0.2 ) * 100 + 5, ( i + 2) * 20 ) );
}
lathe.setPoints(points);
lathe.build();

vector<glm::vec2> getPoints() const;

Returns the points that are going to be rotated.


vector<glm::vec3> getCurrentRotatingPoints() const;

Like getPoints(), but it returns the points at the last angle rotation. See the example example-rotating-points


std::function<glm::vec3(float, int, int)> addOffset;

Lambda function that add an offset to the point position of each rotating point. For example, to add an offset to the y component of point depending on the rotation angle:

lathe.addOffset = [](float angle, int segmentIndex, int pointIndex) {
    auto y = sin(angle*3.0) * 9.0;
    return glm::vec3(0,y,0);
};

std::function<glm::vec2(const vector<glm::vec2> points, float, int, int)> editPoint;

Lambda function that changes the position of the point while rotating. Example:

lathe.editPoint = [offset](const vector<glm::vec2> points, float angle, int segIndex, int pointIndex){
    auto point = points.at(pointIndex);
    glm::vec2 newPoint;

    newPoint.x = point.x * cos(angle*4) * 0.3 + offset.x;
    newPoint.y = point.y * sin(angle*2) * 0.3 + offset.y;

    return newPoint;
};

See the example example-funky-torus.


std::function<ofColor(float, int, int)> computeColor;

Lambda function that changes the color of the point during the rotation. For example:

int totPoints = lathe.points.size();
lathe.computeColor = [totPoints](float angle, int segmentIter, int pointIter) {
    float hue = ofMap(sin(angle*3.), -1, 1, 125, 200);
    return ofColor().fromHsb(hue, 255, 255);
};

See the example example-distorted.

Examples

example-distorted example-distorted

example-editor example-editor

example-rotating-points example-rotating-points

example-funky-torus example-funky-torus