reproduce gluPerspective in openFrameworks w/ ofxFenster and glFrustum

testApp.cpp

// useful as a basis for rendering parts of the image across multiple monitors
// see also http://www.opengl.org/wiki/GluPerspective_code
// and https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/gl/ofGLRenderer.cpp#L315

void testApp::draw(){
    ofxFenster * win = ofxFensterManager::get()->getActiveWindow();
    ofPoint size = win->getWindowSize();
    glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
    float halfFovTan = tanf(60 * PI / 360.0);
    float baseDist = (size.y / 2) / halfFovTan;
    float near = baseDist / 10.f;
    float far = baseDist * 10.f;
    float ymax = near * halfFovTan;
    float xmax = (size.x / size.y) * ymax;
    glFrustum(-xmax, xmax, -ymax, ymax, near, far);
    
    
    glMatrixMode(GL_MODELVIEW);

    // the rest of your draw here
}

👏 thanks for this gist