///////////////////////////////////////////////////////////////////////////////
// Name:        src/common/glcmn.cpp
// Purpose:     wxGLCanvasBase implementation
// Author:      Vadim Zeitlin
// Created:     2007-04-09
// Copyright:   (c) 2007 Vadim Zeitlin <vadim@wxwindows.org>
// Licence:     wxWindows licence
///////////////////////////////////////////////////////////////////////////////

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

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

// for compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#define GL_GLEXT_PROTOTYPES

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#if wxUSE_GLCANVAS

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

#include "wx/glcanvas.h"

// DLL options compatibility check:
#include "wx/build.h"
WX_CHECK_BUILD_OPTIONS("wxGL")

IMPLEMENT_CLASS(wxGLApp, wxApp)

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

wxGLCanvasBase::wxGLCanvasBase()
{
#if WXWIN_COMPATIBILITY_2_8
    m_glContext = NULL;
#endif

    // we always paint background entirely ourselves so prevent wx from erasing
    // it to avoid flicker
    SetBackgroundStyle(wxBG_STYLE_CUSTOM);
}

bool wxGLCanvasBase::SetCurrent(const wxGLContext& context) const
{
    // although on MSW it works even if the window is still hidden, it doesn't
    // work in other ports (notably X11-based ones) and documentation mentions
    // that SetCurrent() can only be called for a shown window, so check for it
    wxASSERT_MSG( IsShownOnScreen(), wxT("can't make hidden GL canvas current") );


    return context.SetCurrent(*static_cast<const wxGLCanvas *>(this));
}

bool wxGLCanvasBase::SetColour(const wxString& colour)
{
    wxColour col = wxTheColourDatabase->Find(colour);
    if ( !col.IsOk() )
        return false;

#ifdef wxHAS_OPENGL_ES
    wxGLAPI::glColor3f((GLfloat) (col.Red() / 256.), (GLfloat) (col.Green() / 256.),
                (GLfloat) (col.Blue() / 256.));
#else
    GLboolean isRGBA;
    glGetBooleanv(GL_RGBA_MODE, &isRGBA);
    if ( isRGBA )
    {
        glColor3f((GLfloat) (col.Red() / 256.), (GLfloat) (col.Green() / 256.),
                (GLfloat) (col.Blue() / 256.));
    }
    else // indexed colour
    {
        GLint pix = GetColourIndex(col);
        if ( pix == -1 )
        {
            wxLogError(_("Failed to allocate colour for OpenGL"));
            return false;
        }

        glIndexi(pix);
    }
#endif
    return true;
}

wxGLCanvasBase::~wxGLCanvasBase()
{
#if WXWIN_COMPATIBILITY_2_8
    delete m_glContext;
#endif // WXWIN_COMPATIBILITY_2_8
}

#if WXWIN_COMPATIBILITY_2_8

wxGLContext *wxGLCanvasBase::GetContext() const
{
    return m_glContext;
}

void wxGLCanvasBase::SetCurrent()
{
    if ( m_glContext )
        SetCurrent(*m_glContext);
}

void wxGLCanvasBase::OnSize(wxSizeEvent& WXUNUSED(event))
{
}

#endif // WXWIN_COMPATIBILITY_2_8

/* static */
bool wxGLCanvasBase::IsExtensionInList(const char *list, const char *extension)
{
    if ( !list )
        return false;

    for ( const char *p = list; *p; p++ )
    {
        // advance up to the next possible match
        p = wxStrstr(p, extension);
        if ( !p )
            break;

        // check that the extension appears at the beginning/ending of the list
        // or is preceded/followed by a space to avoid mistakenly finding
        // "glExtension" in a list containing some "glFunkyglExtension"
        if ( (p == list || p[-1] == ' ') )
        {
            char c = p[strlen(extension)];
            if ( c == '\0' || c == ' ' )
                return true;
        }
    }

    return false;
}

// ============================================================================
// compatibility layer for OpenGL 3 and OpenGL ES
// ============================================================================

static wxGLAPI s_glAPI;

#if wxUSE_OPENGL_EMULATION

#include "wx/vector.h"

static GLenum s_mode;

static GLfloat s_currentTexCoord[2];
static GLfloat s_currentColor[4];
static GLfloat s_currentNormal[3];

// TODO move this into a different construct with locality for all attributes
// of a vertex

static wxVector<GLfloat> s_texCoords;
static wxVector<GLfloat> s_vertices;
static wxVector<GLfloat> s_normals;
static wxVector<GLfloat> s_colors;

static bool s_texCoordsUsed;
static bool s_colorsUsed;
static bool s_normalsUsed;

bool SetState( int flag, bool desired )
{
    bool former = glIsEnabled( flag );
    if ( former != desired )
    {
        if ( desired )
            glEnableClientState(flag);
        else
            glDisableClientState(flag);
    }
    return former;
}

void RestoreState( int flag, bool desired )
{
    if ( desired )
        glEnableClientState(flag);
    else
        glDisableClientState(flag);
}
#endif

wxGLAPI::wxGLAPI()
{
#if wxUSE_OPENGL_EMULATION
    s_mode = 0xFF;
#endif
}

wxGLAPI::~wxGLAPI()
{
}

void wxGLAPI::glFrustum(GLfloat left, GLfloat right, GLfloat bottom,
                            GLfloat top, GLfloat zNear, GLfloat zFar)
{
#if wxUSE_OPENGL_EMULATION
    ::glFrustumf(left, right, bottom, top, zNear, zFar);
#else
    ::glFrustum(left, right, bottom, top, zNear, zFar);
#endif
}

void wxGLAPI::glBegin(GLenum mode)
{
#if wxUSE_OPENGL_EMULATION
    if ( s_mode != 0xFF )
    {
        wxFAIL_MSG("nested glBegin");
    }

    s_mode = mode;
    s_texCoordsUsed = false;
    s_colorsUsed = false;
    s_normalsUsed = false;

    s_texCoords.clear();
    s_normals.clear();
    s_colors.clear();
    s_vertices.clear();
#else
    ::glBegin(mode);
#endif
}

void wxGLAPI::glTexCoord2f(GLfloat s, GLfloat t)
{
#if wxUSE_OPENGL_EMULATION
    if ( s_mode == 0xFF )
    {
        wxFAIL_MSG("glTexCoord2f called outside glBegin/glEnd");
    }

    else
    {
        s_texCoordsUsed = true;
        s_currentTexCoord[0] = s;
        s_currentTexCoord[1] = t;
    }
#else
    ::glTexCoord2f(s,t);
#endif
}

void wxGLAPI::glVertex3f(GLfloat x, GLfloat y, GLfloat z)
{
#if wxUSE_OPENGL_EMULATION
    if ( s_mode == 0xFF )
    {
        wxFAIL_MSG("glVertex3f called outside glBegin/glEnd");
    }
    else
    {
        s_texCoords.push_back(s_currentTexCoord[0]);
        s_texCoords.push_back(s_currentTexCoord[1]);

        s_normals.push_back(s_currentNormal[0]);
        s_normals.push_back(s_currentNormal[1]);
        s_normals.push_back(s_currentNormal[2]);

        s_colors.push_back(s_currentColor[0]);
        s_colors.push_back(s_currentColor[1]);
        s_colors.push_back(s_currentColor[2]);
        s_colors.push_back(s_currentColor[3]);

        s_vertices.push_back(x);
        s_vertices.push_back(y);
        s_vertices.push_back(z);
    }
#else
    ::glVertex3f(x,y,z);
#endif
}

void wxGLAPI::glNormal3f(GLfloat nx, GLfloat ny, GLfloat nz)
{
#if wxUSE_OPENGL_EMULATION
    if ( s_mode == 0xFF )
        ::glNormal3f(nx,ny,nz);
    else
    {
        s_normalsUsed = true;
        s_currentNormal[0] = nx;
        s_currentNormal[1] = ny;
        s_currentNormal[2] = nz;
    }
#else
    ::glNormal3f(nx,ny,nz);
#endif
}

void wxGLAPI::glColor4f(GLfloat r, GLfloat g, GLfloat b, GLfloat a)
{
#if wxUSE_OPENGL_EMULATION
    if ( s_mode == 0xFF )
        ::glColor4f(r,g,b,a);
    else
    {
        s_colorsUsed = true;
        s_currentColor[0] = r;
        s_currentColor[1] = g;
        s_currentColor[2] = b;
        s_currentColor[3] = a;
    }
#else
    ::glColor4f(r,g,b,a);
#endif
}

void wxGLAPI::glColor3f(GLfloat r, GLfloat g, GLfloat b)
{
#if wxUSE_OPENGL_EMULATION
    glColor4f(r,g,b,1.0);
#else
    ::glColor3f(r,g,b);
#endif
}

void wxGLAPI::glEnd()
{
#if wxUSE_OPENGL_EMULATION
    bool formerColors = SetState( GL_COLOR_ARRAY, s_colorsUsed );
    bool formerNormals = SetState( GL_NORMAL_ARRAY, s_normalsUsed );
    bool formerTexCoords = SetState( GL_TEXTURE_COORD_ARRAY, s_texCoordsUsed );
    bool formerVertex = glIsEnabled(GL_VERTEX_ARRAY);

    if( !formerVertex )
        glEnableClientState(GL_VERTEX_ARRAY);

    if ( s_colorsUsed )
        glColorPointer( 4, GL_FLOAT, 0, &s_colors[0] );

    if ( s_normalsUsed )
        glNormalPointer( GL_FLOAT, 0, &s_normals[0] );

    if ( s_texCoordsUsed )
        glTexCoordPointer( 2, GL_FLOAT, 0, &s_texCoords[0] );

    glVertexPointer(3, GL_FLOAT, 0, &s_vertices[0]);
    glDrawArrays( s_mode, 0, s_vertices.size() / 3 );

    if ( s_colorsUsed != formerColors )
        RestoreState( GL_COLOR_ARRAY, formerColors );

    if ( s_normalsUsed != formerNormals )
        RestoreState( GL_NORMAL_ARRAY, formerColors );

    if ( s_texCoordsUsed != formerTexCoords )
        RestoreState( GL_TEXTURE_COORD_ARRAY, formerColors );

    if( !formerVertex )
        glDisableClientState(GL_VERTEX_ARRAY);

    s_mode = 0xFF;
#else
    ::glEnd();
#endif
}

#endif // wxUSE_GLCANVAS

