在wxWidgets中执行简单openGL显示循环时场景重绘不完整

Question

我正致力于在wxWidets openGl应用程序中实现一个简单的动画循环。我遇到了一个问题，循环迭代在每次迭代显示之前没有完全绘制屏幕。似乎.1s足以完全描绘出简单的场景……有谁能告诉我为什么它可能不会呢？

谢谢!

#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

当涉及到OpenGL时，GLUT并不是必须使用的东西。GLUT是第三方框架，wxWidgets是第三方框架。两者都实现了一个事件循环。

您不应该将它们混合在一起。只使用wxWidgets就可以了，它提供了一个非常好的OpenGL小部件。