// ----- BEGIN: TryWin.h
#include <FL/Fl_Gl_Window.H>

class TryWin : public Fl_Gl_Window
{
public:
    TryWin(int x1, int y1, int x2, int y2, int index0 = -1);
    
    void draw();
    void initGL();
};

//  ----- END: TryWin.h
//  ----- BEGIN: TryWin.cpp

#include <openGL/GLU.h>
#include <GLUT/GLUT.h>

TryWin::TryWin(int x1, int y1, int x2, int y2, int index0)
:       Fl_Gl_Window(x1, y1, x2, y2, "TryWin") // THIS SETS THE OPENGL VIEWPORT
{
}

void TryWin::initGL() {
    glClear(GL_COLOR_BUFFER_BIT + GL_DEPTH_BUFFER_BIT);
}
void TryWin::draw(){
    if (!visible_r()) return;   // don't draw invisible widget
    if (!valid()) {
      glLoadIdentity();
      glViewport(0, 0, pixel_w(), pixel_h());
    }
    // Draw using the FLTK widget's rgb color()         //                     RRGGBBCC
                                                        //                     --------
    float r = (color() >> (8*3) & 0xff) / 255.0;        // get red component 0xff000000
    float g = (color() >> (8*2) & 0xff) / 255.0;        // get grn component 0x00ff0000
    float b = (color() >> (8*1) & 0xff) / 255.0;        // get blu component 0x0000ff00
    glClearColor(r, g, b, 1.0);
    glClear(GL_COLOR_BUFFER_BIT + GL_DEPTH_BUFFER_BIT);
    glFlush();
}

// ----- END: TryWin.cpp
// ----- BEGIN: TryFLTK.cpp

#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Box.H>

int main(int argc, char **argv) {
    Fl_Window *mainwin = new Fl_Window(800,180);
    {
        // Positions of these subwindows are relative to the mainwin's upper/left
        Fl_Window *leftwin = new TryWin(20,20, 200, 140, 1);
        leftwin->align(FL_ALIGN_CENTER);
        leftwin->color(0x88000000);     // dark red
        leftwin->end();
        
        Fl_Window *midwin = new TryWin(120, 20, 200, 150, 2);
        midwin->align(FL_ALIGN_CENTER);
        midwin->color(0xdd000000);      // red
        midwin->end();
        
        Fl_Window *rightwin = new Fl_Window(410, 20, 200, 140);
        rightwin->align(FL_ALIGN_CENTER);
        rightwin->color(0x00880000);    // dark green
        rightwin->begin();
        {
            // Child box coords within subwindow
            Fl_Box *box = new Fl_Box(20,20,80,80,"R Box");
            box->color(0x00dd0000);     // green
            box->box(FL_FLAT_BOX);
        }
        rightwin->end();
    }
    mainwin->end(); 
    mainwin->resizable(mainwin); 
    mainwin->show(argc, argv); 
    return Fl::run(); 
} 

//  END: TryFLTK.cpp