src/gl_start.cxx

   1 //
   2 // "$Id: gl_start.cxx 8368 2011-02-04 23:32:53Z manolo $"
   3 //
   4 // OpenGL context routines 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 // You MUST use gl_visual() to select the default visual before doing
  29 // show() of any windows.  Mesa will crash if you try to use a visual
  30 // not returned by glxChooseVisual.
  31
  32 // This does not work with Fl_Double_Window's!  It will try to draw
  33 // into the front buffer.  Depending on the system this will either
  34 // crash or do nothing (when pixmaps are being used as back buffer
  35 // and GL is being done by hardware), work correctly (when GL is done
  36 // with software, such as Mesa), or draw into the front buffer and
  37 // be erased when the buffers are swapped (when double buffer hardware
  38 // is being used)
  39
  40 #include <config.h>
  41 #if HAVE_GL
  42
  43 #include <FL/Fl.H>
  44 #include <FL/Fl_Window.H>
  45 #include <FL/x.H>
  46 #include <FL/fl_draw.H>
  47 #include "Fl_Gl_Choice.H"
  48
  49 static GLContext context;
  50 static int clip_state_number=-1;
  51 static int pw, ph;
  52
  53 #ifdef WIN32
  54 static Fl_Gl_Choice* gl_choice;
  55 #endif
  56
  57 #ifdef __APPLE__
  58 static Fl_Gl_Choice* gl_choice;
  59 #endif
  60
  61 Fl_Region XRectangleRegion(int x, int y, int w, int h); // in fl_rect.cxx
  62
  63 /** Creates an OpenGL context */
  64 void gl_start() {
  65   if (!context) {
  66 #if defined(USE_X11)
  67     context = fl_create_gl_context(fl_visual);
  68 #elif defined(WIN32)
  69     if (!gl_choice) Fl::gl_visual(0);
  70     context = fl_create_gl_context(Fl_Window::current(), gl_choice);
  71 #elif defined(__APPLE_QUARTZ__)
  72     // warning: the Quartz version should probably use Core GL (CGL) instead of AGL
  73     context = fl_create_gl_context(Fl_Window::current(), gl_choice);
  74 #else
  75 #  error Unsupported platform
  76 #endif
  77   }
  78   fl_set_gl_context(Fl_Window::current(), context);
  79 #if !defined(WIN32) && !defined(__APPLE__)
  80   glXWaitX();
  81 #endif
  82   if (pw != Fl_Window::current()->w() || ph != Fl_Window::current()->h()) {
  83     pw = Fl_Window::current()->w();
  84     ph = Fl_Window::current()->h();
  85     glLoadIdentity();
  86     glViewport(0, 0, pw, ph);
  87     glOrtho(0, pw, 0, ph, -1, 1);
  88     glDrawBuffer(GL_FRONT);
  89   }
  90   if (clip_state_number != fl_graphics_driver->fl_clip_state_number) {
  91     clip_state_number = fl_graphics_driver->fl_clip_state_number;
  92     int x, y, w, h;
  93     if (fl_clip_box(0, 0, Fl_Window::current()->w(), Fl_Window::current()->h(),
  94                     x, y, w, h)) {
  95       fl_clip_region(XRectangleRegion(x,y,w,h));
  96       glScissor(x, Fl_Window::current()->h()-(y+h), w, h);
  97       glEnable(GL_SCISSOR_TEST);
  98     } else {
  99       glDisable(GL_SCISSOR_TEST);
 100     }
 101   }
 102 }
 103
 104 /** Releases an OpenGL context */
 105 void gl_finish() {
 106   glFlush();
 107 #if !defined(WIN32) && !defined(__APPLE__)
 108   glXWaitGL();
 109 #endif
 110 }
 111
 112 int Fl::gl_visual(int mode, int *alist) {
 113   Fl_Gl_Choice *c = Fl_Gl_Choice::find(mode,alist);
 114   if (!c) return 0;
 115 #if defined(USE_X11)
 116   fl_visual = c->vis;
 117   fl_colormap = c->colormap;
 118 #elif defined(WIN32)
 119   gl_choice = c;
 120 #elif defined(__APPLE_QUARTZ__)
 121   // warning: the Quartz version should probably use Core GL (CGL) instead of AGL
 122   gl_choice = c;
 123 #else
 124 #  error Unsupported platform
 125 #endif
 126   return 1;
 127 }
 128 #endif
 129
 130 //
 131 // End of "$Id: gl_start.cxx 8368 2011-02-04 23:32:53Z manolo $".
 132 //