[work 28] Flow Field

[work 28] Flow Field

Movie

Source code

about

  • Flow Fieldを漂うパーティクル
  • 動画の前半はFlowFieldのベクトル表示あり

file

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#include "ofMain.h"
#include "ofApp.h"

//================================
int main( ){

    // 4K:4096x2160
    // 2K:2048x1080
    // FullHD:1920x1080
    // HD:1440x1080
    // HD720p:1280x720
    // DVD:720x480
    // setup the GL context
	ofSetupOpenGL(1280,720, OF_WINDOW);

	// this kicks off the running of my app
	// can be OF_WINDOW or OF_FULLSCREEN
	// pass in width and height too:
	ofRunApp( new ofApp());

}
#pragma once

#include "ofMain.h"

#include "FlowField.hpp"
#include "Particle.hpp"


class ofApp : public ofBaseApp{
	public:
    ofApp();
    ~ofApp();
    
		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);
    
private:
    std::vector<unique_ptr<Particle>> particles;
    unique_ptr<FlowField> ff;
};
#include "ofApp.h"


ofApp::ofApp(){
    
}

ofApp::~ofApp(){
    
}

//--------------------------------------------------------------
void ofApp::setup(){
    double fps = 30;
    
    ofSetFrameRate(fps);
    ofBackground(0);
    ofSetBackgroundAuto(true);
    
    ff = make_unique<FlowField>(20);
    ff->setup();
}

//--------------------------------------------------------------
void ofApp::update(){
    for (int i = 0; i < 500; i++) {
        particles.push_back(make_unique<Particle>(ofVec2f(ofRandomWidth(), ofRandomHeight())));
    }
    
    ff->update();
    
    for (unique_ptr<Particle> &p : particles) {
        p->follow(ff);
        p->update();
    }
    ofRemove(particles, Particle::shouldRemoveOffScreen);
}

//--------------------------------------------------------------
void ofApp::draw(){
    if (ofGetFrameNum() < 30 * 15) {
        ff->display();
    }
    
    for (unique_ptr<Particle> &p : particles) {
        p->display();
    }
}
#ifndef FlowField_hpp
#define FlowField_hpp

#include <stdio.h>
#include "ofMain.h"


class FlowField {
public:
    FlowField(int r);
    ~FlowField();
    void setup();
    void update();
    void display();
    ofVec2f lookup(ofVec2f pos);
private:
    int cols, rows;
    int resolution;
    float xoff, yoff, zoff;
    std::vector<std::vector<ofVec2f>> field;
};
#endif /* FlowField_hpp */
#include "FlowField.hpp"


FlowField::FlowField(int r)
{
    resolution = r;
    cols = ofGetWidth() / resolution;
    rows = ofGetHeight() / resolution;
    field.assign(cols, std::vector<ofVec2f>(rows, ofVec2f(0, 0)));
}


FlowField::~FlowField()
{
    
}


void FlowField::setup()
{
    zoff = 0;
}


void FlowField::update()
{
    xoff = 0;
    for (int x = 0; x < cols; x++) {
        yoff = 0;
        for (int y = 0; y < rows; y++) {
            float theta = ofMap(ofNoise(xoff, yoff, zoff), 0, 1, 0, TWO_PI);
            ofVec2f dir = ofVec2f(std::cos(theta), std::sin(theta));
            field[x][y] = dir.normalize();
            yoff += 0.05;
        }
        xoff += 0.05;
    }
    zoff += 0.01;
}


void FlowField::display()
{
    for (int x = 0; x < cols; x++) {
        for (int y = 0; y < rows; y++) {
            ofPushMatrix();
            ofTranslate(x * resolution, y * resolution);
            ofNoFill();
            ofSetColor(255);
            ofDrawRectangle(0, 0, resolution, resolution);
            
            ofVec2f c = ofVec2f(resolution / 2, resolution / 2);
            int len = resolution * 3 / 4;
            ofVec2f t0 = c - (field[x][y] * len / 2);
            ofVec2f t1 = c + (field[x][y] * len / 2);
            ofSetColor(255, 255, 0);
            ofDrawLine(t0.x, t0.y, t1.x, t1.y);
            ofPopMatrix();
        }
    }
}


ofVec2f FlowField::lookup(ofVec2f pos)
{
    int col = (int)ofClamp(pos.x / resolution, 0, cols - 1);
    int row = (int)ofClamp(pos.y / resolution, 0, rows - 1);
    return field[col][row];
}
#ifndef Particle_hpp
#define Particle_hpp

#include <stdio.h>
#include "ofMain.h"
#include "FlowField.hpp"


class Particle {
public:
    Particle(ofVec2f l);
    ~Particle();
    void update();
    void display();
    
    void follow(unique_ptr<FlowField> &flow);
    void applyForce(ofVec2f force);
    
    static bool shouldRemoveOffScreen(unique_ptr<Particle> &v);
private:
    ofVec2f getLocation();
    void setVelocity();
    
    ofColor color;
    ofVec2f location;
    ofVec2f velocity;
    ofVec2f acceleration;
    float radius;
    float maxforce;
    float maxspeed;
    float tx;
};
#endif /* Particle_hpp */
#include "Particle.hpp"


bool Particle::shouldRemoveOffScreen(unique_ptr<Particle> &p)
{
    return !ofRectangle(0, 0, ofGetWidth(), ofGetHeight()).inside(p->getLocation());
}


Particle::Particle(ofVec2f l)
{
    color = ofColor(255);
    maxspeed = 3;
    maxforce = 0.15;
    acceleration = ofVec2f(0, 0);
    velocity = ofVec2f(0, 0);
    location = l;
    radius = 1;
    tx = 0;
}


Particle::~Particle()
{
    
}


void Particle::update()
{
    location += velocity;
    acceleration *= 0;
}


void Particle::display()
{
    ofPushMatrix();
    ofFill();
    ofSetColor(color);
    ofTranslate(location.x, location.y);
    ofDrawCircle(0, 0, radius);
    ofPopMatrix();
}


void Particle::follow(unique_ptr<FlowField> &flow)
{
    ofVec2f desired = flow->lookup(location);
    desired *= maxspeed;
    
    ofVec2f steer = desired - velocity;
    steer.limit(maxforce);
    applyForce(steer);
}


void Particle::applyForce(ofVec2f force)
{
    acceleration += force;
    setVelocity();
}


ofVec2f Particle::getLocation()
{
    return location;
}


void Particle::setVelocity()
{
    velocity += acceleration;
    velocity.limit(maxspeed);
}

Link to the reference page

ソースコードで使用したAPIの中から要点になりそうなものをいくつか選んでリストアップしました。

categoryAPI/Lib
openframeworksofUtils ofRemove

Development environment

  • openframeworks 0.10.1
  • c++
  • macOS
  • Xcode