CODEWITHSUNDEEP
c++openglglutcairofreeglut
user1095108
user1095108

Reputation: 14603

error with cairo + freeglut combination

I make a GL context with freeglut like this:

glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_STENCIL);

and a draw with cairo like this:

  if (!device_)
  {
    device_ = cairo_glx_device_create(glXGetCurrentDisplay(),
      glXGetCurrentContext());
  }
  // else do nothing

  auto const surface(cairo_gl_surface_create_for_window(device_,
    glXGetCurrentDrawable(), width, height));

  auto const cr(cairo_create(surface));

  // draw using cairo calls

  cairo_destroy(cr);
  cairo_gl_surface_swapbuffers(surface); // !!!
  cairo_surface_destroy(surface);

If I don't call cairo_gl_surface_swapbuffers(), but call glutSwapBuffers(), nothing shows, but there is an error:

X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  156 (GLX)
  Minor opcode of failed request:  11 (X_GLXSwapBuffers)
  Serial number of failed request:  69
  Current serial number in output stream:  72

But, if I call cairo_gl_surface_swapbuffers(), but don't call glutSwapBuffers(), the drawing will show and there will be no error. How can I call glutSwapBuffers(), not cairo_gl_surface_swapbuffers() and not trigger the error? I'd like to mix other content alongside cairo content.

Upvotes: 1

Views: 358

Answers (1)

Uli Schlachter
Uli Schlachter

Reputation: 9867

The function cairo_gl_surface_swapbuffers should be equivalent to calling cairo_surface_flush and afterwards calling the right function for swapping buffers.

So I guess you are looking for cairo_surface_flush(surface)?

Upvotes: 1

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