#include "wxgl.h"

BEGIN_EVENT_TABLE(wxGL,wxGLCanvas)
    EVT_PAINT(wxGL::OnPaint)
    EVT_SIZE(wxGL::OnSize)
    EVT_ERASE_BACKGROUND(wxGL::OnEraseBackground)
END_EVENT_TABLE()

wxGL::wxGL(wxWindow *parent, wxWindowID id,
        const wxPoint& pos,
        const wxSize& size,
        long style, const wxString& name,int* attribList )
    : wxGLCanvas(parent, (wxGLCanvas*) NULL, id, pos, size,
        style|wxFULL_REPAINT_ON_RESIZE , name, attribList )
{
    if ( InitGL() )
    {
    }
}

wxGL::~wxGL()
{
}

void wxGL::OnEraseBackground(wxEraseEvent& WXUNUSED(event))
{
  // Do nothing, to avoid flashing.
}

void wxGL::OnSize(wxSizeEvent& event)
{
    event.Skip();

    ResizeGL();
}

void wxGL::OnPaint( wxPaintEvent& WXUNUSED(event) )
{
    wxPaintDC dc(this);

    RenderScene();
}

void wxGL::OnFullScreen(wxCommandEvent& event)
{
//    fullscreen = event.IsChecked();
}

bool wxGL::InitGL()
{
    if (GetContext())
    {
        SetCurrent();

        glShadeModel(GL_SMOOTH);		// Enable Smooth Shading
        glClearColor(0.0f, 0.0f, 0.0f, 0.5f);	// Black Background
        glClearDepth(1.0f);			// Depth Buffer Setup
        glEnable(GL_DEPTH_TEST);		// Enables Depth Testing
        glDepthFunc(GL_LEQUAL);		// The Type Of Depth Testing To Do
        // Really Nice Perspective Calculations
        glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
    }

    return true;
}

void wxGL::ResizeGL()
{
    if (GetContext())
    {
        SetCurrent();

        int w, h;
        GetClientSize(&w, &h);

        if (h==0)       // Prevent A Divide By Zero By
        {
            h=1;	// Making Height Equal One
        }

        glViewport(0,0,w,h);	// Reset The Current Viewport

        // If I use the following code, nothing will shown on screen!!!!!
//        glMatrixMode(GL_PROJECTION);	// Select The Projection Matrix
//        glLoadIdentity();		// Reset The Projection Matrix
//
//        // Calculate The Aspect Ratio Of The Window
//        gluPerspective(45.0f,(GLfloat)w/(GLfloat)h,0.1f,100.0f);
//
//        glMatrixMode(GL_MODELVIEW);	// Select The Modelview Matrix
//        glLoadIdentity();

        glOrtho(-1.0f, 1.0f, -1.0f, 1.0, 1.0f, -1.0f);
    }
}

void wxGL::RenderScene()
{
    if (!GetContext()) return;

    SetCurrent();
        // Clear Screen And Depth Buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();	// Reset The Current Modelview Matrix

	glBegin(GL_TRIANGLES);	// Drawing Using Triangles
		glVertex3f( 0.0f, 1.0f, 0.0f);	// Top
		glVertex3f(-1.0f,-1.0f, 0.0f);	// Bottom Left
		glVertex3f( 1.0f,-1.0f, 0.0f);	// Bottom Right
	glEnd();				// Finished Drawing The Triangle

    glFlush();
    SwapBuffers();
}

/////////////////////////////////////////
// inside myframe's constructor, I use the following code to create 
// wxGLCanvas based object

	wxInt32 attrib[] = {
		WX_GL_RGBA,
		WX_GL_DEPTH_SIZE,
		32,
		WX_GL_DOUBLEBUFFER,
		0,
	};

        gl =new wxGL(this,-1,wxPoint(0,0),wxSize(w,h),0,"",&attrib[0]);

void wxGL::RenderScene(){    if (!GetContext()) return;    SetCurrent();        // Clear Screen And Depth Buffer	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	glLoadIdentity();	// Reset The Current Modelview Matrix	glBegin(GL_TRIANGLES);	// Drawing Using Triangles		glVertex3f( 0.0f, 1.0f, -4.0f);	// Top		glVertex3f(-1.0f,-1.0f, -4.0f);	// Bottom Left		glVertex3f( 1.0f,-1.0f, -4.0f);	// Bottom Right	glEnd();				// Finished Drawing The Triangle    glFlush();    SwapBuffers();}