many lines from wall to wall

gistfile1.txt

#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){

}

//--------------------------------------------------------------
void ofApp::update(){

}



//--------------------------------------------------------------
void ofApp::draw(){

    ofBackground(0);
    
    // make a polyline which is the screen dimensions
    ofPolyline screen;
    screen.addVertex(ofPoint(0,0));
    screen.addVertex(ofPoint(1024,0));
    screen.addVertex(ofPoint(1024, 1024));
    screen.addVertex(ofPoint(0, 1024));
    screen.setClosed(true);
    
    float f = ofGetElapsedTimef();
    ofPoint anglePt = ofPoint(cos(f), sin(f));
    ofSetColor(255,255,255,20);
    for (int i = 0; i < 20000; i++){
        int randomWall = ofRandom(0,4);
        int randomOtherWall = (int) (randomWall + ofRandom(1,3)) % 4;
        
        float pctA = ofRandom(0,1);
        float pctB = ofRandom(0,1);
        
        ofPoint a = screen[randomWall] * (1-pctA) + screen[(randomWall + 1) % 4] * (pctA);
        ofPoint b = screen[randomOtherWall] * (1-pctB) + screen[(randomOtherWall + 1) % 4] * (pctB);
        
        
        ofPoint intersects;
        float dist = ofMap(sin(f), -1, 1, 0, 512);
        
        bool bIntersects = ofLineSegmentIntersection(a, b, ofPoint(512, 512) -  dist*anglePt, ofPoint(512,512) + dist*anglePt, intersects);
        if (bIntersects){
            ofDrawLine(a,b);
        }
        
    }
    
    
    
    
}

//--------------------------------------------------------------
void ofApp::keyPressed(int key){

}

//--------------------------------------------------------------
void ofApp::keyReleased(int key){

}

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

}

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

}

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

}

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

}

//--------------------------------------------------------------
void ofApp::mouseEntered(int x, int y){

}

//--------------------------------------------------------------
void ofApp::mouseExited(int x, int y){

}

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

}

//--------------------------------------------------------------
void ofApp::gotMessage(ofMessage msg){

}

//--------------------------------------------------------------
void ofApp::dragEvent(ofDragInfo dragInfo){ 

}