src/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 "wx/setup.h"
  18
  19 #if wxUSE_GLCANVAS
  20
  21 #include "wx/glcanvas.h"
  22 #include "wx/utils.h"
  23 #include "wx/app.h"
  24
  25 #include <Xm/Xm.h>
  26 #include "wx/motif/private.h"
  27
  28 #ifdef OLD_MESA
  29 // workaround for bug in Mesa's glx.c
  30 static int bitcount( unsigned long n )
  31 {
  32     int bits;
  33     for (bits=0; n>0;) {
  34         if(n & 1) bits++;
  35         n = n >> 1;
  36     }
  37     return bits;
  38 }
  39 #endif
  40
  41 /*
  42  * GLCanvas implementation
  43  */
  44
  45 IMPLEMENT_CLASS(wxGLCanvas, wxScrolledWindow)
  46
  47 wxGLCanvas::wxGLCanvas(wxWindow *parent,
  48                        wxWindowID id,
  49                        const wxPoint& pos,
  50                        const wxSize& size,
  51                        long style,
  52                        const wxString& name,
  53                        int *attrib_list, const wxPalette& palette)
  54           : wxScrolledWindow(parent, id, pos, size, style, name)
  55 {
  56     XVisualInfo *vi, vi_templ;
  57     XWindowAttributes xwa;
  58     int val, n;
  59
  60     Display* display = (Display*) GetXDisplay();
  61
  62     glx_cx = 0;
  63     // Check for the presence of the GLX extension
  64     if(!glXQueryExtension(display, NULL, NULL)) {
  65         wxDebugMsg("wxGLCanvas: GLX extension is missing\n");
  66         return;
  67     }
  68
  69     if(attrib_list) {
  70         // Get an appropriate visual
  71         vi = glXChooseVisual(display, DefaultScreen(display), attrib_list);
  72         if(!vi) return;
  73
  74         // Here we should make sure that vi is the same visual as the
  75         // one used by the xwindow drawable in wxCanvas.  However,
  76         // there is currently no mechanism for this in wx_canvs.cc.
  77     } else {
  78         // By default, we use the visual of xwindow
  79         XGetWindowAttributes(display, (Window) GetXWindow(), &xwa);
  80         vi_templ.visualid = XVisualIDFromVisual(xwa.visual);
  81         vi = XGetVisualInfo(display, VisualIDMask, &vi_templ, &n);
  82         if(!vi) return;
  83         glXGetConfig(display, vi, GLX_USE_GL, &val);
  84         if(!val) return;
  85         // Basically, this is it.  It should be possible to use vi
  86         // in glXCreateContext() below.  But this fails with Mesa.
  87         // I notified the Mesa author about it; there may be a fix.
  88 #ifdef OLD_MESA
  89         // Construct an attribute list matching the visual
  90         int a_list[32];
  91         n = 0;
  92         if(vi->c_class==TrueColor || vi->c_class==DirectColor) { // RGBA visual
  93             a_list[n++] = GLX_RGBA;
  94             a_list[n++] = GLX_RED_SIZE;
  95             a_list[n++] = bitcount(vi->red_mask);
  96             a_list[n++] = GLX_GREEN_SIZE;
  97             a_list[n++] = bitcount(vi->green_mask);
  98             a_list[n++] = GLX_BLUE_SIZE;
  99             a_list[n++] = bitcount(vi->blue_mask);
 100             glXGetConfig(display, vi, GLX_ALPHA_SIZE, &val);
 101             a_list[n++] = GLX_ALPHA_SIZE;
 102             a_list[n++] = val;
 103         } else { // Color index visual
 104             glXGetConfig(display, vi, GLX_BUFFER_SIZE, &val);
 105             a_list[n++] = GLX_BUFFER_SIZE;
 106             a_list[n++] = val;
 107         }
 108         a_list[n] = None;
 109         XFree(vi);
 110         vi = glXChooseVisual(display, DefaultScreen(display), a_list);
 111         if(!vi) return;
 112 #endif /* OLD_MESA */
 113     }
 114
 115     // Create the GLX context and make it current
 116     glx_cx = glXCreateContext(display, vi, 0, GL_TRUE);
 117 #ifndef OLD_MESA
 118     XFree(vi);
 119 #endif
 120     SetCurrent();
 121 }
 122
 123 wxGLCanvas::~wxGLCanvas(void)
 124 {
 125     Display* display = (Display*) GetXDisplay();
 126     if(glx_cx) glXDestroyContext(display, glx_cx);
 127 }
 128
 129 void wxGLCanvas::SwapBuffers()
 130 {
 131     Display* display = (Display*) GetXDisplay();
 132     if(glx_cx) glXSwapBuffers(display, (Window) GetXWindow());
 133 }
 134
 135 void wxGLCanvas::SetCurrent()
 136 {
 137     Display* display = (Display*) GetXDisplay();
 138     if(glx_cx) glXMakeCurrent(display, (Window) GetXWindow(), glx_cx);
 139 }
 140
 141 void wxGLCanvas::SetColour(const char *col)
 142 {
 143     wxColour *the_colour = wxTheColourDatabase->FindColour(col);
 144     if(the_colour) {
 145         GLboolean b;
 146         glGetBooleanv(GL_RGBA_MODE, &b);
 147         if(b) {
 148             glColor3ub(the_colour->Red(),
 149                     the_colour->Green(),
 150                     the_colour->Blue());
 151         } else {
 152             GLint pix = (GLint)the_colour->m_pixel;
 153             if(pix == -1) {
 154                 XColor exact_def;
 155                 exact_def.red = (unsigned short)the_colour->Red() << 8;
 156                 exact_def.green = (unsigned short)the_colour->Green() << 8;
 157                 exact_def.blue = (unsigned short)the_colour->Blue() << 8;
 158                 exact_def.flags = DoRed | DoGreen | DoBlue;
 159                 if(!XAllocColor((Display*) GetXDisplay(), (Colormap) wxTheApp->GetMainColormap(GetXDisplay()), &exact_def)) {
 160                     wxDebugMsg("wxGLCanvas: cannot allocate color\n");
 161                     return;
 162                 }
 163                 pix = the_colour->m_pixel = exact_def.pixel;
 164             }
 165             glIndexi(pix);
 166         }
 167     }
 168 }
 169
 170 #endif
 171     // wxUSE_GLCANVAS
 172