[work 66] Band

Movie

Source code

about

• 以下を繰り返して帯状の線を描く
  • 点A、点Bの位置を決める
  • AB間の等間隔の位置にある点の座標を取得する
  • 点ABを移動し、同様にAB間の点の座標を取得する
  • 移動前後の点を結ぶ線を描く
  • 点ABの移動は、FlowFieldに従う

file

• 上部にあるファイル名が表示されているボタンを押すと、表示されるファイルが切り替わります
• 別ウィンドウ表示したい時や行番号などが無いRawMode表示したい時は、コード内右上のボタンを押してください（ボタンはマウスオーバーすると表示されます）

#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 "Band.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::shared_ptr<Band> band;
    std::shared_ptr<FlowField> ff;
};

#include "ofApp.h"


ofApp::ofApp(){
    
}

ofApp::~ofApp(){
    
}

//--------------------------------------------------------------
void ofApp::setup(){
    double fps = 30;
    
    
    ofSetFrameRate(fps);
    ofBackground(0);
    ofSetBackgroundAuto(true);
    ofSetVerticalSync(true);
    
    ff = make_shared<FlowField>(80);
    ff->setup();
    
    band = make_shared<Band>();
    band->setup();
}

//--------------------------------------------------------------
void ofApp::update(){
    ff->update();
    band->follow(ff);
    band->update();
}

//--------------------------------------------------------------
void ofApp::draw(){
    band->display();
}

//--------------------------------------------------------------
void ofApp::keyPressed(int key){
    if (key == 's') {
        ofImage img;
        img.grabScreen(0, 0, ofGetWidth(), ofGetHeight());
        img.save("screenshot.png");
    }
}

#ifndef Band_hpp
#define Band_hpp

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

#include "FlowField.hpp"

#define MAX_LINE (100)


class Band {
public:
    Band();
    ~Band();
    void setup();
    void update();
    void display();
    void follow(shared_ptr<FlowField> &flowfield);
    
private:
    std::array<std::vector<ofVec2f>, MAX_LINE> points;
    std::array<ofColor, MAX_LINE> colors;
    ofVec2f start, end;
    
    ofFbo fbo;
};
#endif /* Band_hpp */

#include "Band.hpp"


Band::Band()
{
    
}


Band::~Band()
{
    
}


void Band::setup()
{
    start = ofVec2f(10, 10);
    end = ofVec2f(10, ofGetHeight() - 10);
    
    fbo.allocate(ofGetWidth(), ofGetHeight(), GL_RGBA, 4);
    fbo.begin();
    ofClear(0);
    fbo.end();
    
    for (int i = 0; i < colors.size(); i++) {
        colors.at(i) = ofColor(255, 255, 255, 30);
    }
}


void Band::update()
{
    ofVec2f band = end - start;
    float len = band.length();
    ofVec2f unit = band.normalize();
    
    for (int i = 0; i < points.size(); i++) {
        float d = (len / points.size()) * i;
        points.at(i).push_back(start + unit * d);
    }
    
    ofEnableBlendMode(OF_BLENDMODE_SCREEN);
    fbo.begin();
    ofNoFill();
    ofSetLineWidth(1);
    for (int i = 0; i < points.size(); i++) {
        if (points.at(i).size() > 1) {
            ofSetColor(colors.at(i));
            auto itr = points.at(i).rbegin();
            ofVec2f pre = *(itr + 1);
            ofVec2f current = *(itr);
            ofDrawLine(pre, current);
        }
    }
    fbo.end();
}


void Band::display()
{
    fbo.draw(0, 0);
}


void Band::follow(shared_ptr<FlowField> &flowfield)
{
    Flow fs = flowfield->lookup(start);
    Flow fe = flowfield->lookup(end);
    
    start += fs.direction * ofMap(fs.force, -1, 1, 3, 5);
    end += fe.direction * ofMap(fe.force, -1, 1, 3, 5);
}

#ifndef FlowField_hpp
#define FlowField_hpp

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

struct Flow {
    ofVec2f direction;
    float force;
};

class FlowField {
public:
    FlowField(int r);
    ~FlowField();
    void setup();
    void update();
    void display();
    Flow lookup(ofVec2f pos);
private:
    int cols, rows;
    int resolution;
    float xoff, yoff, zoff0, zoff1;
    std::vector<std::vector<Flow>> flow;
};
#endif /* FlowField_hpp */

#include "FlowField.hpp"


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


FlowField::~FlowField()
{
    
}


void FlowField::setup()
{
    zoff0 = ofRandom(0, 1000);
    zoff1 = ofRandom(1000, 2000);
}


void FlowField::update()
{
    xoff = 0;
    for (int x = 0; x < cols; x++) {
        yoff = 0;
        for (int y = 0; y < rows; y++) {
            float theta = ofMap(ofSignedNoise(xoff, yoff, zoff0), -1, 1, -PI, PI);
            ofVec2f dir = ofVec2f(std::cos(theta), std::sin(theta));
            Flow f;
            f.direction = dir.normalize();
            f.force = ofSignedNoise(xoff, yoff, zoff1);
            flow[x][y] = f;
            yoff += 0.05;
        }
        xoff += 0.05;
    }
    zoff0 += 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 - (flow[x][y].direction * len / 2);
            ofVec2f t1 = c + (flow[x][y].direction * len / 2);
            ofSetColor(255, 255, 0);
            ofDrawLine(t0.x, t0.y, t1.x, t1.y);
            ofPopMatrix();
        }
    }
}


Flow 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 flow[col][row];
}

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。

Development environment

• openframeworks 0.10.1
• c++
• macOS
• Xcode