ofxHeadlessFbo

Introduction

This is a simple addon implementing the basic 2D drawing functions that don't utilize OpenGL. Inspired from the Adafruit GFX Library. The shapes are drawn directly to an buffer of ofPixels instead of ofTextures.

This addon is intended to be used in applications that run headless, for example a Raspberry Pi controlling LED strips without a monitor connected (thus unable to run OpenGL).

I hope you find this useful. Please open an issue if you have suggestions or find bugs, and feel free to contribute improvements.

Installation

Download the addon into your openframeworks/addons/ directory or install using git: git clone https://github.com/ghztomash/ofxHeadlessFbo.git

Use

Before drawing into the buffer you need to first allocate it's size and define the pixel color type.

ofxHeadlessFbo hfbo;

void ofApp::setup(){
    // allocate virtual FBO buffer
    hfbo.allocate(800, 300, OF_PIXELS_RGBA);
}

void ofApp::update(){
    hfbo.clear(ofColor(0,0,0,0));

    hfbo.setColor(ofColor(0,255,0));
    hfbo.drawTriangle( 0, size, size/2.0, 0, size, size);
    hfbo.setColor(ofColor(0,0,255,127));
    hfbo.drawRectangle(size/4.0,size/4.0,size/2.0,size/2.0);
    hfbo.setColor(ofColor(255,255,255,127));
    hfbo.drawCircle(size/2.0,size/2.0, size/4.0);
}

The supported shapes are

You can draw the buffer directly onto the screen with

void ofApp::draw(){
    // draw the virtual FBO
    hfbo.draw(10, 10);
}

or get the pixel data and transmit over UDP to LED strips.

Tested

MacOS, Linux and Windows

License

BSD

Credits

Created and maintained by Tomash GHz Ported sections from Adafruit GFX Library