ofDocsexamples math vectorMathExample src ofApp.cpp
#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){
	ofSetVerticalSync(true);

	nPts = 0;
	rotateAmount = {0, 0, 1};
	speedOfRotation = ofDegToRad(0.5f);

	ofBackground(255,255,255);

	glm::vec3 center(ofGetWidth()/2, ofGetHeight()/2, 0);

	xAxisMin = {-100,   0,    0};
	xAxisMax = { 100,   0,    0};
	yAxisMin = {   0,-100,    0};
	yAxisMax = {   0, 100,    0};
	zAxisMin = {   0,   0, -100};
	zAxisMax = {   0,   0,  100};

	xAxisMin += center;
	xAxisMax += center;
	yAxisMin += center;
	yAxisMax += center;
	zAxisMin += center;
	zAxisMax += center;

	bDrawnAnything = false;     // added this cause theo saw this example
								// and was like "how do I tell zach that a rotating
								// cross is not that interesting ??"  before realizing
								// that one should draw :)

}

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

     // rotation occurs around 0,0,0 position.
     // since 0,0,0 is the top left corner, we need to:
     // (A) move over,
     // (B) rotate
     // (C) move back
     // this could all be one for loop, but broken out here for
     // clarity on the steps:

     glm::vec3 center(ofGetWidth()/2, ofGetHeight()/2,0);

     // move the points so that their center (ofGetW/2, ofGetH/2) is at 0,0,0
     for (int i = 0; i < nPts; i++){
        pts[i]-= center;
     }

     // rotate the points
     for (int i = 0; i < nPts; i++){
         pts[i] = glm::rotate(pts[i],speedOfRotation, rotateAmount);
     }

     // move them back
     for (int i = 0; i < nPts; i++){
        pts[i]+= center;
     }


     xAxisMin -= center;
     xAxisMax -= center;
     yAxisMin -= center;
     yAxisMax -= center;
     zAxisMin -= center;
     zAxisMax -= center;


     xAxisMin = glm::rotate(xAxisMin, speedOfRotation, rotateAmount);
     xAxisMax = glm::rotate(xAxisMax, speedOfRotation, rotateAmount);
     yAxisMin = glm::rotate(yAxisMin, speedOfRotation, rotateAmount);
     yAxisMax = glm::rotate(yAxisMax, speedOfRotation, rotateAmount);
     zAxisMin = glm::rotate(zAxisMin, speedOfRotation, rotateAmount);
     zAxisMax = glm::rotate(zAxisMax, speedOfRotation, rotateAmount);

     xAxisMin += center;
     xAxisMax += center;
     yAxisMin += center;
     yAxisMax += center;
     zAxisMin += center;
     zAxisMax += center;
}

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

     ofSetHexColor(0x000000);
     ofNoFill();
     ofBeginShape();
     for (int i = 0; i < nPts; i++){
         ofVertex(pts[i].x, pts[i].y);
     }
     ofEndShape();

     string info = "speed of rotation (a/z): " + ofToString(speedOfRotation,3) + "\n" +
                  "rotateAmount in x (s/x): " + ofToString(rotateAmount.x,3) + "\n" +
                  "rotateAmount in y (d/c): " + ofToString(rotateAmount.y,3) + "\n" +
                  "rotateAmount in z (f/v): " + ofToString(rotateAmount.z,3);

     ofFill();
     ofSetHexColor(0xE5A93F);
     ofDrawRectangle(10,10,300,70);
     ofSetHexColor(0x000000);
     ofDrawBitmapString(info,30,30);


     ofSetColor(50,50,255);
     ofNoFill();
     ofBeginShape();
        ofVertex(xAxisMin.x, xAxisMin.y, xAxisMin.z);
        ofVertex(xAxisMax.x, xAxisMax.y, xAxisMax.z);
     ofEndShape();
     ofBeginShape();
        ofVertex(yAxisMin.x, yAxisMin.y, yAxisMin.z);
        ofVertex(yAxisMax.x, yAxisMax.y, yAxisMax.z);
     ofEndShape();
     ofBeginShape();
        ofVertex(zAxisMin.x, zAxisMin.y, zAxisMin.z);
        ofVertex(zAxisMax.x, zAxisMax.y, zAxisMax.z);
     ofEndShape();


    if (bDrawnAnything == false){
        ofSetColor(0,0,0);
        ofDrawBitmapString("draw something!", ofGetWidth()/2 + 100,ofGetHeight()/2 + 20);
    }

}

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

    switch (key){
        case 'a':
            speedOfRotation += 0.001f;
            break;
        case 'z':
            speedOfRotation -= 0.001f;
            break;
        case 's':
            rotateAmount.x += 0.05f;
            break;
        case 'x':
             rotateAmount.x -= 0.05f;
            break;
        case 'd':
            rotateAmount.y += 0.05f;
            break;
        case 'c':
             rotateAmount.y -= 0.05f;
            break;
        case 'f':
            rotateAmount.z += 0.05f;
            break;
        case 'v':
             rotateAmount.z -= 0.05f;
            break;
    }
}

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

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

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

     bDrawnAnything = true;

     if (nPts < MAX_N_PTS){
        pts[nPts].x = x;
        pts[nPts].y = y;
        nPts++;
     }
}

//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){
     nPts = 0;
}

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

}