wxWidgets/samples/opengl/cube/cube.cpp

///////////////////////////////////////////////////////////////////////////////
// Name:        cube.cpp
// Purpose:     wxGLCanvas demo program
// Author:      Julian Smart
// Modified by: Vadim Zeitlin to use new wxGLCanvas API (2007-04-09)
// Created:     04/01/98
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart
// Licence:     wxWindows licence
///////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#pragma hdrstop
#endif

#ifndef WX_PRECOMP
#include "wx/wx.h"
#endif

#if !wxUSE_GLCANVAS
    #error "OpenGL required: set wxUSE_GLCANVAS to 1 and rebuild the library"
#endif

#include "cube.h"

#if !defined(__WXMSW__) && !defined(__WXPM__)
    #include "../../sample.xpm"
#endif

// ----------------------------------------------------------------------------
// helper functions
// ----------------------------------------------------------------------------

static void CheckGLError()
{
    GLenum errLast = GL_NO_ERROR;

    for ( ;; )
    {
        GLenum err = glGetError();
        if ( err == GL_NO_ERROR )
            return;

        // normally the error is reset by the call to glGetError() but if
        // glGetError() itself returns an error, we risk looping forever here
        // so check that we get a different error than the last time
        if ( err == errLast )
        {
            wxLogError(_T("OpenGL error state couldn't be reset."));
            return;
        }

        errLast = err;

        wxLogError(_T("OpenGL error %d"), err);
    }
}

// function to draw the texture for cube faces
static wxImage DrawDice(int size, unsigned num)
{
    wxASSERT_MSG( num >= 1 && num <= 6, _T("invalid dice index") );

    const int dot = size/16;        // radius of a single dot
    const int gap = 5*size/32;      // gap between dots

    wxBitmap bmp(size, size);
    wxMemoryDC dc;
    dc.SelectObject(bmp);
    dc.SetBackground(*wxWHITE_BRUSH);
    dc.Clear();
    dc.SetBrush(*wxBLACK_BRUSH);

    // the upper left and lower right points
    if ( num != 1 )
    {
        dc.DrawCircle(gap + dot, gap + dot, dot);
        dc.DrawCircle(size - gap - dot, size - gap - dot, dot);
    }

    // draw the central point for odd dices
    if ( num % 2 )
    {
        dc.DrawCircle(size/2, size/2, dot);
    }

    // the upper right and lower left points
    if ( num > 3 )
    {
        dc.DrawCircle(size - gap - dot, gap + dot, dot);
        dc.DrawCircle(gap + dot, size - gap - dot, dot);
    }

    // finally those 2 are only for the last dice
    if ( num == 6 )
    {
        dc.DrawCircle(gap + dot, size/2, dot);
        dc.DrawCircle(size - gap - dot, size/2, dot);
    }

    dc.SelectObject(wxNullBitmap);

    return bmp.ConvertToImage();
}

// ============================================================================
// implementation
// ============================================================================

// ----------------------------------------------------------------------------
// TestGLContext
// ----------------------------------------------------------------------------

TestGLContext::TestGLContext(wxGLCanvas *canvas)
             : wxGLContext(canvas)
{
    SetCurrent(*canvas);

    // set up the parameters we want to use
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_TEXTURE_2D);

    // add slightly more light, the default lighting is rather dark
    GLfloat ambient[] = { 0.5, 0.5, 0.5, 0.5 };
    glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);

    // set viewing projection
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-0.5f, 0.5f, -0.5f, 0.5f, 1.0f, 3.0f);

    // create the textures to use for cube sides: they will be reused by all
    // canvases (which is probably not critical in the case of simple textures
    // we use here but could be really important for a real application where
    // each texture could take many megabytes)
    glGenTextures(WXSIZEOF(m_textures), m_textures);

    for ( unsigned i = 0; i < WXSIZEOF(m_textures); i++ )
    {
        glBindTexture(GL_TEXTURE_2D, m_textures[i]);

        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

        const wxImage img(DrawDice(256, i + 1));

        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, img.GetWidth(), img.GetHeight(), 
                     0, GL_RGB, GL_UNSIGNED_BYTE, img.GetData());
    }

    CheckGLError();
}

void TestGLContext::DrawRotatedCube(float xangle, float yangle)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0f, 0.0f, -2.0f);
    glRotatef(xangle, 1.0f, 0.0f, 0.0f);
    glRotatef(yangle, 0.0f, 1.0f, 0.0f);

    // draw six faces of a cube of size 1 centered at (0, 0, 0)
    glBindTexture(GL_TEXTURE_2D, m_textures[0]);
    glBegin(GL_QUADS);
        glNormal3f( 0.0f, 0.0f, 1.0f);
        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
        glTexCoord2f(1, 0); glVertex3f(-0.5f, 0.5f, 0.5f);
        glTexCoord2f(1, 1); glVertex3f(-0.5f,-0.5f, 0.5f);
        glTexCoord2f(0, 1); glVertex3f( 0.5f,-0.5f, 0.5f);
    glEnd();

    glBindTexture(GL_TEXTURE_2D, m_textures[1]);
    glBegin(GL_QUADS);
        glNormal3f( 0.0f, 0.0f,-1.0f);
        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
        glTexCoord2f(1, 0); glVertex3f(-0.5f, 0.5f,-0.5f);
        glTexCoord2f(1, 1); glVertex3f( 0.5f, 0.5f,-0.5f);
        glTexCoord2f(0, 1); glVertex3f( 0.5f,-0.5f,-0.5f);
    glEnd();

    glBindTexture(GL_TEXTURE_2D, m_textures[2]);
    glBegin(GL_QUADS);
        glNormal3f( 0.0f, 1.0f, 0.0f);
        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
        glTexCoord2f(1, 0); glVertex3f( 0.5f, 0.5f,-0.5f);
        glTexCoord2f(1, 1); glVertex3f(-0.5f, 0.5f,-0.5f);
        glTexCoord2f(0, 1); glVertex3f(-0.5f, 0.5f, 0.5f);
    glEnd();

    glBindTexture(GL_TEXTURE_2D, m_textures[3]);
    glBegin(GL_QUADS);
        glNormal3f( 0.0f,-1.0f, 0.0f);
        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
        glTexCoord2f(1, 0); glVertex3f( 0.5f,-0.5f,-0.5f);
        glTexCoord2f(1, 1); glVertex3f( 0.5f,-0.5f, 0.5f);
        glTexCoord2f(0, 1); glVertex3f(-0.5f,-0.5f, 0.5f);
    glEnd();

    glBindTexture(GL_TEXTURE_2D, m_textures[4]);
    glBegin(GL_QUADS);
        glNormal3f( 1.0f, 0.0f, 0.0f);
        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
        glTexCoord2f(1, 0); glVertex3f( 0.5f,-0.5f, 0.5f);
        glTexCoord2f(1, 1); glVertex3f( 0.5f,-0.5f,-0.5f);
        glTexCoord2f(0, 1); glVertex3f( 0.5f, 0.5f,-0.5f);
    glEnd();

    glBindTexture(GL_TEXTURE_2D, m_textures[5]);
    glBegin(GL_QUADS);
        glNormal3f(-1.0f, 0.0f, 0.0f);
        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
        glTexCoord2f(1, 0); glVertex3f(-0.5f,-0.5f, 0.5f);
        glTexCoord2f(1, 1); glVertex3f(-0.5f, 0.5f, 0.5f);
        glTexCoord2f(0, 1); glVertex3f(-0.5f, 0.5f,-0.5f);
    glEnd();

    glFlush();

    CheckGLError();
}


// ----------------------------------------------------------------------------
// MyApp: the application object
// ----------------------------------------------------------------------------

IMPLEMENT_APP(MyApp)

bool MyApp::OnInit()
{
    if ( !wxApp::OnInit() )
        return false;

    new MyFrame();

    return true;
}

int MyApp::OnExit()
{
    delete m_glContext;

    return wxApp::OnExit();
}

TestGLContext& MyApp::GetContext(wxGLCanvas *canvas)
{
    if ( !m_glContext )
    {
        // Create the OpenGL context for the first window which needs it:
        // subsequently created windows will all share the same context.
        m_glContext = new TestGLContext(canvas);
    }

    m_glContext->SetCurrent(*canvas);

    return *m_glContext;
}

// ----------------------------------------------------------------------------
// TestGLCanvas
// ----------------------------------------------------------------------------

BEGIN_EVENT_TABLE(TestGLCanvas, wxGLCanvas)
    EVT_PAINT(TestGLCanvas::OnPaint)
    EVT_KEY_DOWN(TestGLCanvas::OnKeyDown)
END_EVENT_TABLE()

TestGLCanvas::TestGLCanvas(wxWindow *parent)
    // With perspective OpenGL graphics, the wxFULL_REPAINT_ON_RESIZE style
    // flag should always be set, because even making the canvas smaller should
    // be followed by a paint event that updates the entire canvas with new
    // viewport settings.
    : wxGLCanvas(parent, wxID_ANY, NULL /* attribs */,
                 wxDefaultPosition, wxDefaultSize,
                 wxFULL_REPAINT_ON_RESIZE)
{
    m_xangle =
    m_yangle = 30;
}

void TestGLCanvas::OnPaint(wxPaintEvent& WXUNUSED(event))
{
    // This is required even though dc is not used otherwise.
    wxPaintDC dc(this);

    // Set the OpenGL viewport according to the client size of this canvas.
    // This is done here rather than in a wxSizeEvent handler because our
    // OpenGL rendering context (and thus viewport setting) is used with
    // multiple canvases: If we updated the viewport in the wxSizeEvent
    // handler, changing the size of one canvas causes a viewport setting that
    // is wrong when next another canvas is repainted.
    const wxSize ClientSize = GetClientSize();

    glViewport(0, 0, ClientSize.x, ClientSize.y);

    // Render the graphics and swap the buffers.
    wxGetApp().GetContext(this).DrawRotatedCube(m_xangle, m_yangle);
    SwapBuffers();
}

void TestGLCanvas::OnKeyDown( wxKeyEvent& event )
{
    float *p = NULL;

    bool inverse = false;

    switch ( event.GetKeyCode() )
    {
        case WXK_RIGHT:
            inverse = true;
            // fall through

        case WXK_LEFT:
            // rotate around Y axis
            p = &m_yangle;
            break;

        case WXK_DOWN:
            inverse = true;
            // fall through

        case WXK_UP:
            // rotate around X axis
            p = &m_xangle;
            break;

        default:
            event.Skip();
            return;
    }

    float angle = 5;
    if ( inverse )
        angle = -angle;

    *p += angle;

    Refresh(false);
}


// ----------------------------------------------------------------------------
// MyFrame: main application window
// ----------------------------------------------------------------------------

BEGIN_EVENT_TABLE(MyFrame, wxFrame)
    EVT_MENU(wxID_NEW, MyFrame::OnNewWindow)
    EVT_MENU(wxID_CLOSE, MyFrame::OnClose)
END_EVENT_TABLE()

MyFrame::MyFrame()
       : wxFrame(NULL, wxID_ANY, _T("wxWidgets OpenGL Cube Sample"))
{
    new TestGLCanvas(this);

    SetIcon(wxICON(sample));

    // Make a menubar
    wxMenu *menu = new wxMenu;
    menu->Append(wxID_NEW);
    menu->AppendSeparator();
    menu->Append(wxID_CLOSE);
    wxMenuBar *menuBar = new wxMenuBar;
    menuBar->Append(menu, _T("&Cube"));

    SetMenuBar(menuBar);

    CreateStatusBar();

    SetClientSize(400, 400);
    Show();

    // test IsDisplaySupported() function:
    static const int attribs[] = { WX_GL_RGBA, WX_GL_DOUBLEBUFFER, 0 };
    wxLogStatus("Double-buffered display %s supported",
                wxGLCanvas::IsDisplaySupported(attribs) ? "is" : "not");
}

void MyFrame::OnClose(wxCommandEvent& WXUNUSED(event))
{
    // true is to force the frame to close
    Close(true);
}

void MyFrame::OnNewWindow( wxCommandEvent& WXUNUSED(event) )
{
    new MyFrame();
}