Frameworker

Openframeworks Centroid Example

admin — Sun, 31 Oct 2010 10:50:19 +0000

Centroid Example of a Polygon.

Calculation of Centroid and Area of a Polgygon is:
The centroid of a non-self-intersecting closed polygon defined by n vertices (x0,y0), (x1,y1), …, (xn−1,yn−1) is the point (Cx, Cy), where

and where A is the polygon’s signed area,

In these formulas, the vertices are assumed to be numbered in order of their occurrence along the polygon’s perimeter, and the vertex ( xn , yn ) is assumed to be the same as ( x0 , y0 ). Note that if the points are numbered in clockwise order the area A, computed as above, will have a negative sign; but the centroid coordinates will be correct even in this case.

http://en.wikipedia.org/wiki/Centroid

Source Code:

TestApp.h
#pragma once

#include "ofMain.h"


class testApp : public ofBaseApp{

public:
void setup();

void update();

void draw();
void keyPressed  (int key);

void mouseMoved(int x, int y );

void mouseDragged(int x, int y, int button);

void mousePressed(int x, int y, int button);

void mouseReleased(int x, int y, int button);

void windowResized(int w, int h);
struct Point {

float x,y,z,alpha;

float r,g,b;
Point () {

}
Point (float _x,float _y,float _z,float _alpha) {

x = _x;

y = _y;

z = _z;

alpha = _alpha;
r=ofRandom(0,255);

g=ofRandom(0,255);

b=ofRandom(0,255);

}

};
struct Poly {

Point centroid;
float span;

float counter;
float alpha;
bool childNodes;
double area;
vector

points;

vector

children;
Poly() {

calculateArea();
span = ofRandom(0,500);

counter = 0;

childNodes = false;

alpha = 0;

}
void addPoint(float x,float y,float z=0,float alpha=0) {

points.push_back(* new Point(x,y,z,alpha));

area = calculateArea();

calculateCentroid();

}
double calculateArea() {

area = 0;

int j = 0;

for (int i=0;i

area+=points[i].x*points[j].y;

area-=points[i].y*points[j].x;

}
area/=2;

return area;

}
void calculateCentroid() {

float mx=0;

float my=0;

float f;

float j=points.size()-1;
for (int i=0;i                     f=points[i].x*points[j].y-points[j].x*points[i].y;

mx+=(points[i].x+points[j].x)*f;

my+=(points[i].y+points[j].y)*f;

}
f=area*6;
centroid.x = mx/f;

centroid.y = my/f;

}
void draw() {

for (int i=0;i                     ofSetColor(points[i].r,points[i].g,points[i].b,alpha);

ofLine(points[i].x,points[i].y,points[i+1].x,points[i+1].y);

}

ofLine(points[points.size()-1].x,points[points.size()-1].y,points[0].x,points[0].y);
drawCentroid();
if (childNodes) {

for (int i=0;i<3;i++) { 		                children[i].draw(); 		            } 		        } 		        update(); 		    } 		    void drawCentroid() { 		        //ofCircle(centroid.x,centroid.y,2); 		        //ofDrawBitmapString(ofToString(ofRandom(0,9)),centroid.x,centroid.y); 		    }             void update() {                 if (childNodes) {                     return;                 }                 alpha+=100/span;                 counter++;                 if (counter>span && !childNodes) {

childNodes = true;
for (int i=0;i

children.push_back(* new Poly());

children[i].addPoint(points[i].x,points[i].y);

children[i].addPoint(points[i+1].x,points[i+1].y);

children[i].addPoint(centroid.x,centroid.y);

children[i].addPoint(points[i].x,points[i].y);

}

}

}

};

vector structure; }; extern testApp *myApp;

TestApp.cpp
#include "testApp.h" static int span = 1000; static int counter = 0; //-------------------------------------------------------------- void testApp::setup(){ ofBackground(50,50,50); structure.push_back( * new Poly());

structure[0].addPoint(100,100); structure[0].addPoint(500,200); structure[0].addPoint(800,300); structure[0].addPoint(200,600); structure[0].addPoint(150,500);


ofEnableAlphaBlending();

ofEnableSmoothing();

}
//--------------------------------------------------------------

void testApp::update(){

counter++;

if (counter>span) {

counter=0;

structure.clear();
structure.push_back( * new Poly());

structure[0].addPoint(ofRandom(0,100),ofRandom(0,100));

structure[0].addPoint(ofRandom(100,500),ofRandom(100,200));

structure[0].addPoint(ofRandom(500,800),ofRandom(200,400));

structure[0].addPoint(ofRandom(800,1000),ofRandom(400,600));

structure[0].addPoint(ofRandom(100,150),ofRandom(100,400));

}

}
//--------------------------------------------------------------

void testApp::draw(){

structure[0].draw();

}
//--------------------------------------------------------------

void testApp::keyPressed  (int key){
}
//--------------------------------------------------------------

void testApp::mouseMoved(int x, int y ){

}
void testApp::windowResized(int w, int h) {
}
//--------------------------------------------------------------

void testApp::mouseDragged(int x, int y, int button){

}
//--------------------------------------------------------------

void testApp::mousePressed(int x, int y, int button){

}
//--------------------------------------------------------------

void testApp::mouseReleased(int x, int y, int button){
}

Openframeworks Sphere Boids Demo

admin — Wed, 13 Oct 2010 17:14:19 +0000

I’ve translated some code inorder to create a sphere from n number of points.

here it is

void testApp::createSphereFromPoints( const ofxVec3f ¢er, float radius, int segments ) { if( segments < 0 ) return;


float *verts = new float[(segments+1)*2*3];

for( int j = 0; j < segments / 2; j++ ) {

float theta1 = j * 2 * 3.14159f / segments - ( 3.14159f / 2.0f );

float theta2 = (j + 1) * 2 * 3.14159f / segments - ( 3.14159f / 2.0f );
for( int i = 0; i <= segments; i++ ) {

ofxVec3f e, p;

float theta3 = i * 2 * 3.14159f / segments;
e.x = cos( theta1 ) * cos( theta3 );

e.y = sin( theta1 );

e.z = cos( theta1 ) * sin( theta3 );

p = e * radius + center;
verts[i*3*2+0] = p.x;

verts[i*3*2+1] = p.y;

verts[i*3*2+2] = p.z;
e.x = cos( theta2 ) * cos( theta3 );

e.y = sin( theta2 );

e.z = cos( theta2 ) * sin( theta3 );

p = e * radius + center;
verts[i*3*2+3] = p.x;

verts[i*3*2+4] = p.y;

verts[i*3*2+5] = p.z;

spherePoints.push_back(p); } } }

It pushes an number of points to “ofxVec3d spherPoints”. and another function pushes n number of boids into the space with an initial location of a point in over the surface of sphere.

I got that after all:

What I am trying to do is, I want to select randomly 2 points from my sphere, and draw a 3d Bezier line between that two points inorder to get that image

I have the 2d bezier formula, I am looking for 3d version.
src

Openframeworks Text Effects Demo

admin — Tue, 05 Oct 2010 17:01:53 +0000

I’ve tried to create some text effects for openframeworks. Hope you enjoy it.

The source is here.

ofxTextEffects

Art of Code

admin — Tue, 14 Sep 2010 11:31:22 +0000

Here some experiments with the old boid codes which are translated from Daniel Shiffman’s flocking behaviours, the origins of the source are coming from Craig W. Reynold .

3d Boids Source Code

09.September.2010 Roadtrip through the industry to the roots

admin — Mon, 13 Sep 2010 21:50:37 +0000

A nice roadtrip through the industrial zone of Izmit / Kocaeli to Esme. Our first rest place was Hereke its only 100km far from Istanbul. We have eaten a delicious fish at a small restaurant called Mercan.

Then we have continiued our triped to Esme a lovely village of Adapazarı. At the other day we’ve went to Taraklı which is a small village 20kms far from Esme, at Taraklı I am very happy to see a restoration of an ancient Ottoman Han ( inn ). The old people living at the village where coming from the Cuma praying and they were very interested with us, they were happy to see foreigners interested about their village. One of the old person who was a retired imam of the mosque come near to us while I was taking a photo of an ancient door and its remainings. He told me about a Plane Tree which is 600 years old. We’ve also tried to take photos of the tree.

After drinking our traditional Turkish coffee at the villages park, we went to another ancient Ottoman Village which is called Göynük. Göynük is a very important Ottoman Village because of Akşemseddin who is the teacher of Fatih Sultan Mehmet who had conquered Istanbul at 1453 also known as “FATIH THE CONQUERER”. Akşemseddin was a very famous Sofi who is also called as the father of microbiology after his researchs about micro-orgonizms around 1400 AD.

Some more photos from the journey..

Birthday present for a friend

admin — Mon, 16 Aug 2010 22:55:09 +0000

Roadtrips

admin — Thu, 29 Jul 2010 16:29:16 +0000

The roadshow events for the adidas “buformabizim.com” campaign will start tomorrow. I will be going to Erzurum, Kayseri, Trabzon, Antalya, İzmir and Antalya during the event.

Bosphorus Gaz Data Visualisation Software Beta Tests

admin — Thu, 29 Jul 2010 11:30:54 +0000

I’ve completed the data visualisation software for Bosphorus Gaz, which shows the Natural Gas resources around Europe & Asia, each city in the software shows the nearby gaz points, the pipe lines between Russia through other countries and a photo library.

I’ve used Displax’s Multitouch hardware for multitouch gesture recognitions.

Today is the day that Mc Fly arrived, when he went to the Future.

admin — Tue, 06 Jul 2010 20:56:31 +0000

Where is the flying cars working with garbage?

Recording Video & Sound Together

admin — Sun, 20 Jun 2010 22:28:42 +0000

Finally, I am able to record sound & video together.. Thanks to openframeworks forum.. here is the first tests..
Sources

Here how it works…
First you need to add libsnd libraries to your code… I’ve added them to addons/libsound/libsndfile-1.lib
Download libsnd from Mega-Nerd

Then you must add linker options as:
to your codeblocks project file.

*** You must carefully arrange the framerates, otherwise you get sound + video sync problems.

First we save audio track and video separately and then we add the audio track to quicktime file. Finally save them. At the end we have a quicktime movie with sound and also a sound file.

testApp.cpp
#include "testApp.h" #include "stdio.h"


#include 
static bool bRecording = false;

static int myFrameRate = 15;
//--------------------------------------------------------------

void testApp::setup(){
    camWidth 		= 640;	// try to grab at this size.

	camHeight 		= 480;
	vidGrabber.setVerbose(true);

	vidGrabber.initGrabber(camWidth,camHeight);
	saver.listCodecs();

	//saver.setCodecType(17); //ZACH FIX see recording quicktime with sound in sync on of forum

	saver.setCodecQualityLevel(OF_QT_SAVER_CODEC_QUALITY_NORMAL);

	saver.setup(640,480,"data/output.mov");
	ofSetFrameRate(myFrameRate);
	ofBackground(255,255,255);
	// 0 output channels,

	// 2 input channels

	// 22050 samples per second

	// 256 samples per buffer

	// 4 num buffers (latency)
	ofSoundStreamSetup(0,2,this, 44100, 256, 4);

	left = new float[256];

	right = new float[256];
	bufferCounter = 0;

	drawCounter = 0;
    sampleRate = 44100;
    info.format=SF_FORMAT_WAV | SF_FORMAT_PCM_16;

    info.frames = sampleRate*myFrameRate;

    info.samplerate = sampleRate;

    info.channels = 2;

    outfile = sf_open ("data/mydata.wav", SFM_WRITE, &info) ;
    if (!outfile)

        {

            cerr<<"Error opening ["<
        }
}
//--------------------------------------------------------------

void testApp::draw(){

    vidGrabber.draw(20,400);
	// draw the left:

	ofSetColor(0x333333);

	ofRect(100,100,256,200);

	ofSetColor(0xFFFFFF);

	for (int i = 0; i < 256; i++){

		ofLine(100+i,200,100+i,200+left[i]*100.0f);

	}
	// draw the right:

	ofSetColor(0x333333);

	ofRect(600,100,256,200);

	ofSetColor(0xFFFFFF);

	for (int i = 0; i < 256; i++){

		ofLine(600+i,200,600+i,200+right[i]*100.0f);

	}
	ofSetColor(0x333333);

	drawCounter++;

	char reportString[255];

	sprintf(reportString, "buffers received: %i\ndraw routines called: %i\n", bufferCounter,drawCounter);

	ofDrawBitmapString(reportString,80,380);

}
void testApp::update(){
	ofBackground(100,100,100);
	vidGrabber.grabFrame();
	if (bRecording == true){

		saver.addFrame(vidGrabber.getPixels(), 1.0f / myFrameRate);
		//  you can also pass in the frameRate:

		//	saver.addFrame(vidGrabber.getPixels(), 1.0f / 30.0f);  // 30 fps for this frame

		//	saver.addFrame(vidGrabber.getPixels(), 1.0f / 5.0f);   // 5 fps for this frame, etc....
	}
}
static float adder = 0;

//--------------------------------------------------------------

void testApp::audioReceived 	(float * input, int bufferSize, int nChannels){
    if (bRecording){
	// samples are "interleaved"

	for (int i = 0; i < bufferSize; i++){

		left[i] = input[i*2];

		right[i] = input[i*2+1];

	}

	bufferCounter++;

	sf_write_float(outfile, input, bufferSize*2);

    }

}
//--------------------------------------------------------------

void testApp::keyPressed  (int key){
    if (key=='a')

        {

            bRecording = true;

        }
    if (key=='s')

        {

            bRecording = false;

            sf_close(outfile);

        }
    if (key==' ')

        {

            saver.addAudioTrack("data/mydata.wav");

            saver.finishMovie();

        }

}
//--------------------------------------------------------------

void testApp::keyReleased(int key){
}
//--------------------------------------------------------------

void testApp::mouseMoved(int x, int y ){
}
//--------------------------------------------------------------

void testApp::mouseDragged(int x, int y, int button){
}
//--------------------------------------------------------------

void testApp::mousePressed(int x, int y, int button){
}
//--------------------------------------------------------------

void testApp::mouseReleased(int x, int y, int button){
}
//--------------------------------------------------------------

void testApp::resized(int w, int h){

}

testApp.h
#ifndef _TEST_APP #define _TEST_APP


#include "ofMain.h"
#include 

#include "ofxQtVideoSaver.h"
class testApp : public ofBaseApp{
	public:
		void setup();

		void update();

		void draw();
		void keyPressed(int key);

		void keyReleased(int key);

		void mouseMoved(int x, int y );

		void mouseDragged(int x, int y, int button);

		void mousePressed(int x, int y, int button);

		void mouseReleased(int x, int y, int button);

		void resized(int w, int h);
		void audioReceived 	(float * input, int bufferSize, int nChannels);
		float * left;

		float * right;

		int 	bufferCounter;

		int 	drawCounter;
        int      format;

        int      channels;

        int      sampleRate;

        int      sndBuffSize;

        int      sndBuffPos;

        char   * outfilename;

        SNDFILE * outfile;

        SF_INFO    info;
        ofVideoGrabber 		vidGrabber;
		int 				camWidth;

		int 				camHeight;
		ofxQtVideoSaver		saver;
		float * output;

};
#endif