utils/glcanvas/motif/glcanvas.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        glcanvas.cpp
   3 // Purpose:     wxGLCanvas, for using OpenGL with wxWindows 2.0 for Motif.
   4 //              Uses the GLX extension.
   5 // Author:      Julian Smart and Wolfram Gloger
   6 // Modified by:
   7 // Created:     1995, 1999
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) Julian Smart, Wolfram Gloger
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifdef __GNUG__
  14 #pragma implementation "glcanvas.h"
  15 #endif
  16
  17 #include "glcanvas.h"
  18 #include "wx/utils.h"
  19 #include "wx/app.h"
  20
  21 #include <Xm/Xm.h>
  22 #include "wx/motif/private.h"
  23
  24 #ifdef OLD_MESA
  25 // workaround for bug in Mesa's glx.c
  26 static int bitcount( unsigned long n )
  27 {
  28     int bits;
  29     for (bits=0; n>0;) {
  30         if(n & 1) bits++;
  31         n = n >> 1;
  32     }
  33     return bits;
  34 }
  35 #endif
  36
  37 /*
  38  * GLCanvas implementation
  39  */
  40
  41 IMPLEMENT_CLASS(wxGLCanvas, wxScrolledWindow)
  42
  43 wxGLCanvas::wxGLCanvas(wxWindow *parent, wxWindowID id = -1, const wxPoint& pos,
  44   const wxSize& size, long style,
  45   const wxString& name, int *attrib_list, const wxPalette& palette):
  46     wxScrolledWindow(parent, id, pos, size, style, name)
  47 {
  48     XVisualInfo *vi, vi_templ;
  49     XWindowAttributes xwa;
  50     int val, n;
  51
  52     Display* display = (Display*) GetXDisplay();
  53
  54     glx_cx = 0;
  55     // Check for the presence of the GLX extension
  56     if(!glXQueryExtension(display, NULL, NULL)) {
  57         wxDebugMsg("wxGLCanvas: GLX extension is missing\n");
  58         return;
  59     }
  60
  61     if(attrib_list) {
  62         // Get an appropriate visual
  63         vi = glXChooseVisual(display, DefaultScreen(display), attrib_list);
  64         if(!vi) return;
  65
  66         // Here we should make sure that vi is the same visual as the
  67         // one used by the xwindow drawable in wxCanvas.  However,
  68         // there is currently no mechanism for this in wx_canvs.cc.
  69     } else {
  70         // By default, we use the visual of xwindow
  71         XGetWindowAttributes(display, (Window) GetXWindow(), &xwa);
  72         vi_templ.visualid = XVisualIDFromVisual(xwa.visual);
  73         vi = XGetVisualInfo(display, VisualIDMask, &vi_templ, &n);
  74         if(!vi) return;
  75         glXGetConfig(display, vi, GLX_USE_GL, &val);
  76         if(!val) return;
  77         // Basically, this is it.  It should be possible to use vi
  78         // in glXCreateContext() below.  But this fails with Mesa.
  79         // I notified the Mesa author about it; there may be a fix.
  80 #ifdef OLD_MESA
  81         // Construct an attribute list matching the visual
  82         int a_list[32];
  83         n = 0;
  84         if(vi->c_class==TrueColor || vi->c_class==DirectColor) { // RGBA visual
  85             a_list[n++] = GLX_RGBA;
  86             a_list[n++] = GLX_RED_SIZE;
  87             a_list[n++] = bitcount(vi->red_mask);
  88             a_list[n++] = GLX_GREEN_SIZE;
  89             a_list[n++] = bitcount(vi->green_mask);
  90             a_list[n++] = GLX_BLUE_SIZE;
  91             a_list[n++] = bitcount(vi->blue_mask);
  92             glXGetConfig(display, vi, GLX_ALPHA_SIZE, &val);
  93             a_list[n++] = GLX_ALPHA_SIZE;
  94             a_list[n++] = val;
  95         } else { // Color index visual
  96             glXGetConfig(display, vi, GLX_BUFFER_SIZE, &val);
  97             a_list[n++] = GLX_BUFFER_SIZE;
  98             a_list[n++] = val;
  99         }
 100         a_list[n] = None;
 101         XFree(vi);
 102         vi = glXChooseVisual(display, DefaultScreen(display), a_list);
 103         if(!vi) return;
 104 #endif /* OLD_MESA */
 105     }
 106
 107     // Create the GLX context and make it current
 108     glx_cx = glXCreateContext(display, vi, 0, GL_TRUE);
 109 #ifndef OLD_MESA
 110     XFree(vi);
 111 #endif
 112     SetCurrent();
 113 }
 114
 115 wxGLCanvas::~wxGLCanvas(void)
 116 {
 117     Display* display = (Display*) GetXDisplay();
 118     if(glx_cx) glXDestroyContext(display, glx_cx);
 119 }
 120
 121 void wxGLCanvas::SwapBuffers()
 122 {
 123     Display* display = (Display*) GetXDisplay();
 124     if(glx_cx) glXSwapBuffers(display, (Window) GetXWindow());
 125 }
 126
 127 void wxGLCanvas::SetCurrent()
 128 {
 129     Display* display = (Display*) GetXDisplay();
 130     if(glx_cx) glXMakeCurrent(display, (Window) GetXWindow(), glx_cx);
 131 }
 132
 133 void wxGLCanvas::SetColour(const char *col)
 134 {
 135     wxColour *the_colour = wxTheColourDatabase->FindColour(col);
 136     if(the_colour) {
 137         GLboolean b;
 138         glGetBooleanv(GL_RGBA_MODE, &b);
 139         if(b) {
 140             glColor3ub(the_colour->Red(),
 141                        the_colour->Green(),
 142                        the_colour->Blue());
 143         } else {
 144             GLint pix = (GLint)the_colour->m_pixel;
 145             if(pix == -1) {
 146                 XColor exact_def;
 147                 exact_def.red = (unsigned short)the_colour->Red() << 8;
 148                 exact_def.green = (unsigned short)the_colour->Green() << 8;
 149                 exact_def.blue = (unsigned short)the_colour->Blue() << 8;
 150                 exact_def.flags = DoRed | DoGreen | DoBlue;
 151                 if(!XAllocColor((Display*) GetXDisplay(), (Colormap) wxTheApp->GetMainColormap(GetXDisplay()), &exact_def)) {
 152                     wxDebugMsg("wxGLCanvas: cannot allocate color\n");
 153                     return;
 154                 }
 155                 pix = the_colour->m_pixel = exact_def.pixel;
 156             }
 157             glIndexi(pix);
 158         }
 159     }
 160 }
 161