test/gl_overlay.cxx

   1 //
   2 // "$Id: gl_overlay.cxx 8033 2010-12-15 12:11:16Z AlbrechtS $"
   3 //
   4 // OpenGL overlay test program for the Fast Light Tool Kit (FLTK).
   5 //
   6 // Copyright 1998-2010 by Bill Spitzak and others.
   7 //
   8 // This library is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU Library General Public
  10 // License as published by the Free Software Foundation; either
  11 // version 2 of the License, or (at your option) any later version.
  12 //
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // Library General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU Library General Public
  19 // License along with this library; if not, write to the Free Software
  20 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21 // USA.
  22 //
  23 // Please report all bugs and problems on the following page:
  24 //
  25 //     http://www.fltk.org/str.php
  26 //
  27
  28 #include <config.h>
  29 #include <FL/Fl.H>
  30 #include <FL/Fl_Window.H>
  31 #include <FL/Fl_Hor_Slider.H>
  32 #include <FL/Fl_Toggle_Button.H>
  33 #include <FL/math.h>
  34
  35 #if !HAVE_GL
  36 #include <FL/Fl_Box.H>
  37 class shape_window : public Fl_Box {
  38 public:
  39   int sides;
  40   shape_window(int x,int y,int w,int h,const char *l=0)
  41     :Fl_Box(FL_DOWN_BOX,x,y,w,h,l){
  42       label("This demo does\nnot work without GL");
  43   }
  44 };
  45 #else
  46 #include <FL/gl.h>
  47 #include <FL/Fl_Gl_Window.H>
  48
  49 class shape_window : public Fl_Gl_Window {
  50   void draw();
  51   void draw_overlay();
  52 public:
  53   int sides;
  54   int overlay_sides;
  55   shape_window(int x,int y,int w,int h,const char *l=0);
  56 };
  57
  58 shape_window::shape_window(int x,int y,int w,int h,const char *l) :
  59 Fl_Gl_Window(x,y,w,h,l) {
  60   sides = overlay_sides = 3;
  61 }
  62
  63 void shape_window::draw() {
  64 // the valid() property may be used to avoid reinitializing your
  65 // GL transformation for each redraw:
  66   if (!valid()) {
  67     valid(1);
  68     glLoadIdentity();
  69     glViewport(0,0,w(),h());
  70   }
  71 // draw an amazing but slow graphic:
  72   glClear(GL_COLOR_BUFFER_BIT);
  73   //  for (int j=1; j<=1000; j++) {
  74     glBegin(GL_POLYGON);
  75     for (int j=0; j<sides; j++) {
  76       double ang = j*2*M_PI/sides;
  77       glColor3f(float(j)/sides,float(j)/sides,float(j)/sides);
  78       glVertex3f(cos(ang),sin(ang),0);
  79     }
  80     glEnd();
  81   // }
  82 }
  83
  84 void shape_window::draw_overlay() {
  85 // the valid() property may be used to avoid reinitializing your
  86 // GL transformation for each redraw:
  87   if (!valid()) {
  88     valid(1);
  89     glLoadIdentity();
  90     glViewport(0,0,w(),h());
  91   }
  92 // draw an amazing graphic:
  93   gl_color(FL_RED);
  94   glBegin(GL_LINE_LOOP);
  95   for (int j=0; j<overlay_sides; j++) {
  96     double ang = j*2*M_PI/overlay_sides;
  97     glVertex3f(cos(ang),sin(ang),0);
  98   }
  99   glEnd();
 100 }
 101 #endif
 102
 103 // when you change the data, as in this callback, you must call redraw():
 104 void sides_cb(Fl_Widget *o, void *p) {
 105   shape_window *sw = (shape_window *)p;
 106   sw->sides = int(((Fl_Slider *)o)->value());
 107   sw->redraw();
 108 }
 109
 110 #if HAVE_GL
 111 void overlay_sides_cb(Fl_Widget *o, void *p) {
 112   shape_window *sw = (shape_window *)p;
 113   sw->overlay_sides = int(((Fl_Slider *)o)->value());
 114   sw->redraw_overlay();
 115 }
 116 #endif
 117 #include <stdio.h>
 118 int main(int argc, char **argv) {
 119
 120   Fl_Window window(300, 370);
 121
 122   shape_window sw(10, 75, window.w()-20, window.h()-90);
 123 //sw.mode(FL_RGB);
 124   window.resizable(&sw);
 125
 126   Fl_Hor_Slider slider(60, 5, window.w()-70, 30, "Sides:");
 127   slider.align(FL_ALIGN_LEFT);
 128   slider.callback(sides_cb,&sw);
 129   slider.value(sw.sides);
 130   slider.step(1);
 131   slider.bounds(3,40);
 132
 133   Fl_Hor_Slider oslider(60, 40, window.w()-70, 30, "Overlay:");
 134   oslider.align(FL_ALIGN_LEFT);
 135 #if HAVE_GL
 136   oslider.callback(overlay_sides_cb,&sw);
 137   oslider.value(sw.overlay_sides);
 138 #endif
 139   oslider.step(1);
 140   oslider.bounds(3,40);
 141
 142   window.end();
 143   window.show(argc,argv);
 144 #if HAVE_GL
 145   printf("Can do overlay = %d\n", sw.can_do_overlay());
 146   sw.show();
 147   sw.redraw_overlay();
 148 #else
 149   sw.show();
 150 #endif
 151
 152   return Fl::run();
 153 }
 154
 155 //
 156 // End of "$Id: gl_overlay.cxx 8033 2010-12-15 12:11:16Z AlbrechtS $".
 157 //