fltk/test/shape.cxx

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//
// Tiny OpenGL demo program for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2010 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file. If this
// file is missing or damaged, see the license at:
//
// https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
// https://www.fltk.org/bugs.php
//
#include <config.h>
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Hor_Slider.H>
#include <FL/math.h>
#if HAVE_GL
#include <FL/gl.h>
#include <FL/Fl_Gl_Window.H>
class shape_window : public Fl_Gl_Window {
void draw();
public:
int sides;
shape_window(int x,int y,int w,int h,const char *l=0);
};
shape_window::shape_window(int x,int y,int w,int h,const char *l) :
Fl_Gl_Window(x,y,w,h,l) {
sides = 3;
}
void shape_window::draw() {
// the valid() property may be used to avoid reinitializing your
// GL transformation for each redraw:
if (!valid()) {
valid(1);
glLoadIdentity();
glViewport(0, 0, pixel_w(), pixel_h());
}
// draw an amazing graphic:
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(.5,.6,.7);
glBegin(GL_POLYGON);
for (int j=0; j<sides; j++) {
double ang = j*2*M_PI/sides;
glVertex3f(cos(ang),sin(ang),0);
}
glEnd();
}
#else
#include <FL/Fl_Box.H>
class shape_window : public Fl_Box {
public:
int sides;
shape_window(int x,int y,int w,int h,const char *l=0)
:Fl_Box(FL_DOWN_BOX,x,y,w,h,l){
label("This demo does\nnot work without GL");
}
};
#endif
// when you change the data, as in this callback, you must call redraw():
void sides_cb(Fl_Widget *o, void *p) {
shape_window *sw = (shape_window *)p;
sw->sides = int(((Fl_Slider *)o)->value());
sw->redraw();
}
int main(int argc, char **argv) {
Fl::use_high_res_GL(1);
Fl_Window window(300, 330);
// the shape window could be it's own window, but here we make it
// a child window:
shape_window sw(10, 10, 280, 280);
// make it resize:
window.resizable(&sw);
// window.size_range(300,330,0,0,1,1,1);
// add a knob to control it:
Fl_Hor_Slider slider(50, 295, window.w()-60, 30, "Sides:");
slider.align(FL_ALIGN_LEFT);
slider.callback(sides_cb,&sw);
slider.value(sw.sides);
slider.step(1);
slider.bounds(3,40);
window.end();
window.show(argc,argv);
return Fl::run();
}