ParticlesAndNoise.cpp

#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){
	
	ofBackground(246, 189, 208);
	
	gui.setup();
	gui.add(value.set("value", 2.5, 0.00001, 3));
	gui.add(speed.set("speed", 0.045, 0.00001, 3));
	gui.add(drawModes.set("draw modes", 0, 0, 10));
	gui.add(pointSize.set("point size", 1, 0.5, 55));
	gui.add(enableAntiAliasing.set("anti aliasing", true));
	
	drawModeName = "drawmode";
	noisePhase = 0;
	
}

//--------------------------------------------------------------
void ofApp::update(){
	
	if(enableAntiAliasing) {
		ofEnableAntiAliasing();
	} else {
		ofDisableAntiAliasing();
	}
	
	noisePhase += speed;
	
	for(auto &particle : particles) {
		
		float xx = ofMap(particle.p.x, 0, ofGetWidth(), 0, 1) * value;
		float yy = ofMap(particle.p.y, 0, ofGetHeight(), 0, 1) * value;
		float nx = ofSignedNoise(xx + particle.u, yy, particle.u);
		float ny = ofNoise(yy, xx + particle.u, particle.u);
		
		particle.v.x = nx * 2;
		particle.v.y = ny * 10;
		
		ofVec2f vec = ofVec2f(ofGetMouseX(), ofGetMouseY()) - particle.p;
		float len = vec.length();
		
		if (len < 100) {
			vec.normalize();
			particle.v -= vec * 8;
		}
		
		particle.p += particle.v;
		
		if (particle.p.x > ofGetWidth()) {
			particle.p.x = 0;
		}
		if (particle.p.x < 0) {
			particle.p.x = ofGetWidth();
		}
		if (particle.p.y > ofGetHeight()) {
			particle.p.y = 0;
		}
		if (particle.p.y < 0) {
			particle.p.y = ofGetHeight();
		}
	}
}

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

	if (drawModes == 0) {
		drawModeName = "immediate mode";
		
		glPointSize(pointSize);
		ofSetColor(88);
		glBegin(GL_POINTS);
		for(auto &particle : particles) {
			glVertex3f(particle.p.x, particle.p.y, 0);
		}
		glEnd();
		glPointSize(1);
	}
	
	if (drawModes == 1) {
		drawModeName = "vbo mesh";
		
		if (mesh.getVertices().size() != particles.size()) {
			mesh.getVertices().resize(particles.size());
			mesh.setUsage(GL_DYNAMIC_DRAW);
			mesh.setMode(OF_PRIMITIVE_POINTS);
			cout << "allocate " << endl;
		}
		
		
		for(int i=0; i<particles.size(); i++) {
			mesh.setVertex(i, ofVec3f(particles[i].p.x, particles[i].p.y, 0));
		}
		
		glPointSize(pointSize);
		ofSetColor(88);
		mesh.draw();
		glPointSize(1);
	}
	
	/*int step = 3;
	noisePhase += speed;
	for(int x=0; x<ofGetWidth(); x+=step) {
		for(int y=0; y<ofGetHeight(); y+=step) {
			float xx = ofMap(x, 0, ofGetWidth(), 0, 1);
			float yy = ofMap(y, 0, ofGetHeight(), 0, 1);
			float nx = ofNoise(noisePhase - (xx * value), yy * value) * 10;
			float ny = ofNoise(xx * value, yy * value) * 10;
			ofDrawLine(x, y, x+nx, y+ny);
		}
	}*/
	
	string info = "fps " + ofToString(ofGetFrameRate(), 1) + "\n";
	info += ofToString((int)particles.size()) +" particles \n";
	info += drawModeName+" "+ofToString(drawModes);
	ofDrawBitmapStringHighlight(info, gui.getPosition().x, gui.getPosition().y + gui.getHeight() + 20);

	
	gui.draw();
}


//--------------------------------------------------------------
void ofApp::keyPressed(int key){
	if (key == ' ') {
		for(int i=0; i<1000; i++) {
			Particle particle(ofGetMouseX() + ofRandom(-30, 30), ofGetMouseY() + ofRandom(-30, 30));
			particles.push_back(particle);
		}
	}
	
	if (key == 'c') {
		particles.clear();
	}
}

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

}

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

}

//--------------------------------------------------------------
void ofApp::mouseDragged(int x, int y, int button){
	Particle p(ofGetMouseX() + ofRandom(-30, 30), ofGetMouseY() + ofRandom(-30, 30));
	particles.push_back(p);
}

//--------------------------------------------------------------
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){ 

}

ParticlesAndNoise.h

#pragma once

#include "ofMain.h"
#include "ofxGui.h"

class Particle {
public:
	Particle(float x, float y) {
		u = ofRandomf();
		p.set(x, y);
	}
	float u;
	ofVec2f p, v;
};

class ofApp : 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 mouseEntered(int x, int y);
	void mouseExited(int x, int y);
	void windowResized(int w, int h);
	void dragEvent(ofDragInfo dragInfo);
	void gotMessage(ofMessage msg);

	ofxPanel gui;
	ofParameter<int> drawModes;
	ofParameter<bool> enableAntiAliasing;
	ofParameter<float> pointSize;
	ofParameter<float> value, speed;
	
	ofVboMesh mesh;
	float noisePhase;
	string drawModeName;
	vector <Particle> particles;
};