incomplete scene redrawing during simple openGL display loop in wxWidgets - c++

Question

I'm working on getting a simple animation loop going in a wxWidets openGl app. I am having a problem with the loop iterations not fully drawing the screen before displaying it on each iteration. It seems like .1s is more than enough to fully draw the simple scene.... Can anyone give me an idea of why it might not?
Thanks!
#include <wx/wx.h>
#include <wx/glcanvas.h>
#ifdef __WXMAC__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#ifndef WIN32
#include <unistd.h> // FIXME: ¿This work/necessary in Windows?
//Not necessary, but if it was, it needs to be replaced by process.h AND io.h
#endif
//#include "GlBox.cpp"
#include <iostream>
using namespace std;
class wxGLCanvasSubClass: public wxGLCanvas {
public:
wxGLCanvasSubClass(wxFrame* parent);
void Paintit(wxPaintEvent& event);
void Render();
protected:
DECLARE_EVENT_TABLE()
//GlBox myBox;
};
wxGLCanvasSubClass *thing;
static void timerRender(int count)
{
thing->Render();
cout << "render timeout was called \n";
glutTimerFunc(25, timerRender, 0);
}
static void myIdleFunc()
{
cout << "idleing \n";
cout.flush();
}
static void setRender(wxGLCanvasSubClass *thing2)
{
thing = thing2;
cout << "global thing was set \n";
glutTimerFunc(1100, timerRender, 0);
}
BEGIN_EVENT_TABLE(wxGLCanvasSubClass, wxGLCanvas)
EVT_PAINT (wxGLCanvasSubClass::Paintit)
END_EVENT_TABLE()
wxGLCanvasSubClass::wxGLCanvasSubClass(wxFrame *parent)
:wxGLCanvas(parent, wxID_ANY, wxDefaultPosition, wxDefaultSize, 0, wxT("GLCanvas")){
int argc = 1;
char* argv[1] = { wxString((wxTheApp->argv)[0]).char_str() };
/*
NOTE: this example uses GLUT in order to have a free teapot model
to display, to show 3D capabilities. GLUT, however, seems to cause problems
on some systems. If you meet problems, first try commenting out glutInit(),
then try comeenting out all glut code
*/
glutInit(&argc, argv);
glutIdleFunc(myIdleFunc);
}
void wxGLCanvasSubClass::Paintit(wxPaintEvent& WXUNUSED(event)){
Render();
}
void wxGLCanvasSubClass::Render()
{
SetCurrent();
wxPaintDC(this);
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glViewport(0, 0, (GLint)GetSize().x, (GLint)GetSize().y);
glBegin(GL_POLYGON);
glColor3f(1.0, 1.0, 1.0);
glVertex2f(-0.5, -0.5);
glVertex2f(-0.5, 0.5);
glVertex2f(0.5, 0.5);
glVertex2f(0.5, -0.5);
glColor3f(0.4, 0.5, 0.4);
glVertex2f(0.0, -0.8);
glEnd();
// using a little of glut
glColor4f(0,0,1,1);
glutWireTeapot(0.4);
glLoadIdentity();
glColor4f(2,0,1,1);
glutWireTeapot(0.6);
//myBox.getIt();
SwapBuffers();
glFlush();
//
}
class MyApp: public wxApp
{
virtual bool OnInit();
void onIdle(wxIdleEvent& evt);
time_t lastEvent;
bool slept ;
wxGLCanvas * MyGLCanvas;
wxGLCanvasSubClass * myCanvas;
};
IMPLEMENT_APP(MyApp)
bool MyApp::OnInit()
{
slept = false;
lastEvent = time( &lastEvent);
wxFrame *frame = new wxFrame((wxFrame *)NULL, -1, wxT("Hello GL World"), wxPoint(50,50), wxSize(200,200));
myCanvas = new wxGLCanvasSubClass(frame);
frame->Show(TRUE);
Connect( wxID_ANY, wxEVT_IDLE, wxIdleEventHandler(MyApp::onIdle) );
return TRUE;
}
void MyApp::onIdle(wxIdleEvent& evt)
{
if(slept)
{
slept = false;
cout << "event hit " << lastEvent;
myCanvas->Render();
evt.RequestMore();
} else {
cout << "idleing \n " << lastEvent;
usleep(100000);
slept = true;
evt.RequestMore();
}
}

Answer 1

GLUT is not a mandatory thing to use when it comes to OpenGL. GLUT is a third party framework, wxWidgets is a third party framework. And both implement a event loop.
You should not mix these. Just use wxWidgets only, which provides a very fine OpenGL widget.