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