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RenderTexture.cpp

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//---------------------------------------------------------------------------
// File : RenderTexture.cpp
//---------------------------------------------------------------------------
// Copyright (c) 2002-2004 Mark J. Harris
//---------------------------------------------------------------------------
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any
// damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any
// purpose, including commercial applications, and to alter it and
// redistribute it freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you
//    must not claim that you wrote the original software. If you use
//    this software in a product, an acknowledgment in the product
//    documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and
//    must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
//    distribution.
//
// --------------------------------------------------------------------------
// Credits:
// Original RenderTexture class: Mark J. Harris
// Original Render to Depth Texture support: Thorsten Scheuermann
// Linux Copy-to-texture: Eric Werness
// Various Bug Fixes: Daniel (Redge) Sperl 
//                    Bill Baxter
//
// --------------------------------------------------------------------------
/**
* @file RenderTexture.cpp
* 
* Implementation of class RenderTexture.  A multi-format render to 
* texture wrapper.
*/
#pragma warning(disable:4786)

/*
 * Changelog:
 *
 * Jan. 2005, Removed GLEW dependencies, Erik Hofman, Fred Bouvier
 */

#include <simgear/compiler.h>
#include <plib/ul.h>
#ifdef UL_GLX
#  include SG_GL_H
#  define GLX_GLXEXT_PROTOTYPES
#  ifdef __APPLE__
#    include <AGL/agl.h>
#  else
#    include <GL/glx.h>
#  endif
#elif defined UL_WIN32
#  include <windows.h> // MUST be before SG_GL_H and all other GL related include directive
#  include SG_GL_H
#endif
#include "extensions.hxx"
#include "RenderTexture.h"

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>

#ifdef _WIN32
#pragma comment(lib, "gdi32.lib") // required for GetPixelFormat()
#endif

using namespace std;

#ifdef _WIN32
static bool fctPtrInited = false;
/* WGL_ARB_pixel_format */
static wglChoosePixelFormatARBProc wglChoosePixelFormatARBPtr = 0;
static wglGetPixelFormatAttribivARBProc wglGetPixelFormatAttribivARBPtr = 0;
/* WGL_ARB_pbuffer */
static wglCreatePbufferARBProc wglCreatePbufferARBPtr = 0;
static wglGetPbufferDCARBProc wglGetPbufferDCARBPtr = 0;
static wglQueryPbufferARBProc wglQueryPbufferARBPtr = 0;
static wglReleasePbufferDCARBProc wglReleasePbufferDCARBPtr = 0;
static wglDestroyPbufferARBProc wglDestroyPbufferARBPtr = 0;
/* WGL_ARB_render_texture */
static wglBindTexImageARBProc wglBindTexImageARBPtr = 0;
static wglReleaseTexImageARBProc wglReleaseTexImageARBPtr = 0;
#endif

//---------------------------------------------------------------------------
// Function      : RenderTexture::RenderTexture
// Description     : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::RenderTexture()
* @brief Mode-string-based Constructor.
*/ 
RenderTexture::RenderTexture(const char *strMode)
:   _iWidth(0), 
    _iHeight(0), 
    _bIsTexture(false),
    _bIsDepthTexture(false),
    _bHasARBDepthTexture(true),            // [Redge]
#ifdef _WIN32
    _eUpdateMode(RT_RENDER_TO_TEXTURE),
#else
    _eUpdateMode(RT_COPY_TO_TEXTURE),
#endif
    _bInitialized(false),
    _iNumAuxBuffers(0),
    _bIsBufferBound(false),
    _iCurrentBoundBuffer(0),
    _iNumDepthBits(0),
    _iNumStencilBits(0),
    _bFloat(false),
    _bDoubleBuffered(false),
    _bPowerOf2(true),
    _bRectangle(false),
    _bMipmap(false),
    _bShareObjects(false),
    _bCopyContext(false),
#ifdef _WIN32
    _hDC(NULL), 
    _hGLContext(NULL), 
    _hPBuffer(NULL),
    _hPreviousDC(0),
    _hPreviousContext(0),
#elif defined( __APPLE__ )
#else
    _pDisplay(NULL),
    _hGLContext(NULL),
    _hPBuffer(0),
    _hPreviousContext(0),
    _hPreviousDrawable(0),
#endif
    _iTextureTarget(GL_NONE),
    _iTextureID(0),
    _iDepthTextureID(0),
    _pPoorDepthTexture(0) // [Redge]
{
    _iNumColorBits[0] = _iNumColorBits[1] = 
        _iNumColorBits[2] = _iNumColorBits[3] = 0;

#ifdef _WIN32
    _pixelFormatAttribs.push_back(WGL_DRAW_TO_PBUFFER_ARB);
    _pixelFormatAttribs.push_back(true);
    _pixelFormatAttribs.push_back(WGL_SUPPORT_OPENGL_ARB);
    _pixelFormatAttribs.push_back(true);
    
    _pbufferAttribs.push_back(WGL_PBUFFER_LARGEST_ARB);
    _pbufferAttribs.push_back(true);
#elif defined( __APPLE__ )
#else
    _pbufferAttribs.push_back(GLX_RENDER_TYPE_SGIX);
    _pbufferAttribs.push_back(GLX_RGBA_BIT_SGIX);
    _pbufferAttribs.push_back(GLX_DRAWABLE_TYPE_SGIX);
    _pbufferAttribs.push_back(GLX_PBUFFER_BIT_SGIX);
#endif

    _ParseModeString(strMode, _pixelFormatAttribs, _pbufferAttribs);

#ifdef _WIN32
    _pixelFormatAttribs.push_back(0);
    _pbufferAttribs.push_back(0);
#else
    _pixelFormatAttribs.push_back(None);
#endif
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::~RenderTexture
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::~RenderTexture()
* @brief Destructor.
*/ 
RenderTexture::~RenderTexture()
{
    _Invalidate();
}


//---------------------------------------------------------------------------
// Function       : _wglGetLastError
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn wglGetLastError()
* @brief Returns the last windows error generated.
*/ 
#ifdef _WIN32
void _wglGetLastError()
{
#ifdef _DEBUG
    
    DWORD err = GetLastError();
    switch(err)
    {
    case ERROR_INVALID_PIXEL_FORMAT:
        fprintf(stderr, 
                "RenderTexture Win32 Error:  ERROR_INVALID_PIXEL_FORMAT\n");
        break;
    case ERROR_NO_SYSTEM_RESOURCES:
        fprintf(stderr, 
                "RenderTexture Win32 Error:  ERROR_NO_SYSTEM_RESOURCES\n");
        break;
    case ERROR_INVALID_DATA:
        fprintf(stderr, 
                "RenderTexture Win32 Error:  ERROR_INVALID_DATA\n");
        break;
    case ERROR_INVALID_WINDOW_HANDLE:
        fprintf(stderr, 
                "RenderTexture Win32 Error:  ERROR_INVALID_WINDOW_HANDLE\n");
        break;
    case ERROR_RESOURCE_TYPE_NOT_FOUND:
        fprintf(stderr, 
                "RenderTexture Win32 Error:  ERROR_RESOURCE_TYPE_NOT_FOUND\n");
        break;
    case ERROR_SUCCESS:
        // no error
        break;
    default:
        LPVOID lpMsgBuf;
        FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 
            FORMAT_MESSAGE_FROM_SYSTEM | 
            FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL,
            err,
            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
            (LPTSTR) &lpMsgBuf,
            0,
            NULL);
        
        fprintf(stderr, "RenderTexture Win32 Error %d: %s\n", err, lpMsgBuf);
        LocalFree( lpMsgBuf );
        break;
    }
    SetLastError(0);
    
#endif // _DEBUG
}
#endif

//---------------------------------------------------------------------------
// Function       : PrintExtensionError
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn PrintExtensionError( char* strMsg, ... )
* @brief Prints an error about missing OpenGL extensions.
*/ 
00256 void PrintExtensionError( char* strMsg, ... )
{
    fprintf(stderr, 
            "Error: RenderTexture requires the following unsupported "
            "OpenGL extensions: \n");
    char strBuffer[512];
    va_list args;
    va_start(args, strMsg);
#if defined _WIN32 && !defined __CYGWIN__
    _vsnprintf( strBuffer, 512, strMsg, args );
#else
    vsnprintf( strBuffer, 512, strMsg, args );
#endif
    va_end(args);
    
    fprintf(stderr, strMsg);
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::Initialize
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::Initialize(int width, int height, bool shareObjects, bool copyContext);
* @brief Initializes the RenderTexture, sharing display lists and textures if specified.
* 
* This function creates of the p-buffer.  It can only be called once a GL 
* context has already been created.  
*/ 
bool RenderTexture::Initialize(int width, int height,
                                bool shareObjects       /* = true */,
                                bool copyContext        /* = false */)
{
    assert(width > 0 && height > 0);

    _iWidth = width; _iHeight = height;
    _bPowerOf2 = IsPowerOfTwo(width) && IsPowerOfTwo(height);

    _bShareObjects = shareObjects;
    _bCopyContext  = copyContext;

    // Check if this is an NVXX GPU and verify necessary extensions.
    if (!_VerifyExtensions())
        return false;
    
    if (_bInitialized)
        _Invalidate();

#ifdef _WIN32
    // Get the current context.
    HDC hdc = wglGetCurrentDC();
    if (NULL == hdc)
        _wglGetLastError();
    HGLRC hglrc = wglGetCurrentContext();
    if (NULL == hglrc)
        _wglGetLastError();
    
    int iFormat = 0;
    unsigned int iNumFormats;
    
    if (_bCopyContext)
    {
        // Get the pixel format for the on-screen window.
        iFormat = GetPixelFormat(hdc);
        if (iFormat == 0)
        {
            fprintf(stderr, 
                    "RenderTexture Error: GetPixelFormat() failed.\n");
            return false;
        }
    }
    else 
    {
        if (!wglChoosePixelFormatARBPtr(hdc, &_pixelFormatAttribs[0], NULL, 
                                     1, &iFormat, &iNumFormats))
        {
            fprintf(stderr, 
                "RenderTexture Error: wglChoosePixelFormatARB() failed.\n");
            _wglGetLastError();
            return false;
        }
        if ( iNumFormats <= 0 )
        {
            fprintf(stderr, 
                    "RenderTexture Error: Couldn't find a suitable "
                    "pixel format.\n");
            _wglGetLastError();
            return false;
        }
    }
    
    // Create the p-buffer.    
    _hPBuffer = wglCreatePbufferARBPtr(hdc, iFormat, _iWidth, _iHeight, 
                                    &_pbufferAttribs[0]);
    if (!_hPBuffer)
    {
        fprintf(stderr, 
                "RenderTexture Error: wglCreatePbufferARB() failed.\n");
        _wglGetLastError();
        return false;
    }
    
    // Get the device context.
    _hDC = wglGetPbufferDCARBPtr( _hPBuffer);
    if ( !_hDC )
    {
        fprintf(stderr, 
                "RenderTexture Error: wglGetGetPbufferDCARB() failed.\n");
        _wglGetLastError();
        return false;
    }
    
    // Create a gl context for the p-buffer.
    if (_bCopyContext)
    {
        // Let's use the same gl context..
        // Since the device contexts are compatible (i.e. same pixelformat),
        // we should be able to use the same gl rendering context.
        _hGLContext = hglrc;
    }
    else
    {
        _hGLContext = wglCreateContext( _hDC );
        if ( !_hGLContext )
        {
            fprintf(stderr, 
                    "RenderTexture Error: wglCreateContext() failed.\n");
            _wglGetLastError();
            return false;
        }
    }
    
    // Share lists, texture objects, and program objects.
    if( _bShareObjects )
    {
        if( !wglShareLists(hglrc, _hGLContext) )
        {
            fprintf(stderr, 
                    "RenderTexture Error: wglShareLists() failed.\n");
            _wglGetLastError();
            return false;
        }
    }
    
    // Determine the actual width and height we were able to create.
    wglQueryPbufferARBPtr( _hPBuffer, WGL_PBUFFER_WIDTH_ARB, &_iWidth );
    wglQueryPbufferARBPtr( _hPBuffer, WGL_PBUFFER_HEIGHT_ARB, &_iHeight );
    
    _bInitialized = true;
    
    // get the actual number of bits allocated:
    int attrib = WGL_RED_BITS_ARB;
    //int bits[6];
    int value;
    _iNumColorBits[0] = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0;
    attrib = WGL_GREEN_BITS_ARB;
    _iNumColorBits[1] = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0;
    attrib = WGL_BLUE_BITS_ARB;
    _iNumColorBits[2] = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0;
    attrib = WGL_ALPHA_BITS_ARB;
    _iNumColorBits[3] = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0; 
    attrib = WGL_DEPTH_BITS_ARB;
    _iNumDepthBits = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0; 
    attrib = WGL_STENCIL_BITS_ARB;
    _iNumStencilBits = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? value : 0; 
    attrib = WGL_DOUBLE_BUFFER_ARB;
    _bDoubleBuffered = 
        (wglGetPixelFormatAttribivARBPtr(_hDC, iFormat, 0, 1, &attrib, &value)) 
        ? (value?true:false) : false; 
    
#if defined(_DEBUG) | defined(DEBUG)
    fprintf(stderr, "Created a %dx%d RenderTexture with BPP(%d, %d, %d, %d)",
        _iWidth, _iHeight, 
        _iNumColorBits[0], _iNumColorBits[1], 
        _iNumColorBits[2], _iNumColorBits[3]);
    if (_iNumDepthBits) fprintf(stderr, " depth=%d", _iNumDepthBits);
    if (_iNumStencilBits) fprintf(stderr, " stencil=%d", _iNumStencilBits);
    if (_bDoubleBuffered) fprintf(stderr, " double buffered");
    fprintf(stderr, "\n");
#endif

#elif defined( __APPLE__ )
#else // !_WIN32
    _pDisplay = glXGetCurrentDisplay();
    GLXContext context = glXGetCurrentContext();
    int screen = DefaultScreen(_pDisplay);
    XVisualInfo *visInfo;
    
    int iFormat = 0;
    int iNumFormats;
    int attrib = 0;
    
    GLXFBConfigSGIX *fbConfigs;
    int nConfigs;
    
    fbConfigs = glXChooseFBConfigSGIX(_pDisplay, screen, 
                                      &_pixelFormatAttribs[0], &nConfigs);
    
    if (nConfigs == 0 || !fbConfigs) 
    {
        fprintf(stderr,
            "RenderTexture Error: Couldn't find a suitable pixel format.\n");
        return false;
    }
    
    // Pick the first returned format that will return a pbuffer
    for (int i=0;i<nConfigs;i++)
    {
        _hPBuffer = glXCreateGLXPbufferSGIX(_pDisplay, fbConfigs[i], 
                                            _iWidth, _iHeight, NULL);
        if (_hPBuffer) 
        {
            _hGLContext = glXCreateContextWithConfigSGIX(_pDisplay, 
                                                         fbConfigs[i], 
                                                         GLX_RGBA_TYPE, 
                                                         _bShareObjects ? context : NULL, 
                                                         True);
            break;
        }
    }
    
    if (!_hPBuffer)
    {
        fprintf(stderr, 
                "RenderTexture Error: glXCreateGLXPbufferSGIX() failed.\n");
        return false;
    }
    
    if(!_hGLContext)
    {
        // Try indirect
        _hGLContext = glXCreateContext(_pDisplay, visInfo, 
                                       _bShareObjects ? context : NULL, False);
        if ( !_hGLContext )
        {
            fprintf(stderr, 
                    "RenderTexture Error: glXCreateContext() failed.\n");
            return false;
        }
    }
    
    glXQueryGLXPbufferSGIX(_pDisplay, _hPBuffer, GLX_WIDTH_SGIX, 
                           (GLuint*)&_iWidth);
    glXQueryGLXPbufferSGIX(_pDisplay, _hPBuffer, GLX_HEIGHT_SGIX, 
                           (GLuint*)&_iHeight);
    
    _bInitialized = true;
    
    // XXX Query the color format
    
#endif

    
    // Now that the pbuffer is created, allocate any texture objects needed,
    // and initialize them (for CTT updates only).  These must be allocated
    // in the context of the pbuffer, though, or the RT won't work without
    // wglShareLists.
#ifdef _WIN32
    if (false == wglMakeCurrent( _hDC, _hGLContext))
    {
        _wglGetLastError();
        return false;
    }
#elif defined( __APPLE__ )
#else
    _hPreviousContext = glXGetCurrentContext();
    _hPreviousDrawable = glXGetCurrentDrawable();
    
    if (False == glXMakeCurrent(_pDisplay, _hPBuffer, _hGLContext)) 
    {
        return false;
    }
#endif
    
    bool result = _InitializeTextures();   
#ifdef _WIN32
    BindBuffer(WGL_FRONT_LEFT_ARB);
    _BindDepthBuffer();
#endif

    
#ifdef _WIN32 
    // make the previous rendering context current 
    if (false == wglMakeCurrent( hdc, hglrc))
    {
        _wglGetLastError();
        return false;
    }
#elif defined( __APPLE__ )
#else
    if (False == glXMakeCurrent(_pDisplay, 
                                _hPreviousDrawable, _hPreviousContext))
    {
        return false;
    }
#endif

    return result;
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::_Invalidate
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_Invalidate()
* @brief Returns the pbuffer memory to the graphics device.
* 
*/ 
bool RenderTexture::_Invalidate()
{
    _iNumColorBits[0] = _iNumColorBits[1] = 
        _iNumColorBits[2] = _iNumColorBits[3] = 0;
    _iNumDepthBits = 0;
    _iNumStencilBits = 0;
    
    if (_bIsTexture)
        glDeleteTextures(1, &_iTextureID);
    if (_bIsDepthTexture) 
    {
        // [Redge]
        if (!_bHasARBDepthTexture) delete[] _pPoorDepthTexture;
        // [/Redge]
        glDeleteTextures(1, &_iDepthTextureID);
    }
    
#ifdef _WIN32
    if ( _hPBuffer )
    {
        // Check if we are currently rendering in the pbuffer
        if (wglGetCurrentContext() == _hGLContext)
            wglMakeCurrent(0,0);
        if (!_bCopyContext) 
            wglDeleteContext( _hGLContext);
        wglReleasePbufferDCARBPtr( _hPBuffer, _hDC);
        wglDestroyPbufferARBPtr( _hPBuffer );
        _hPBuffer = 0;
        return true;
    }
#elif defined( __APPLE__ )
#else
    if ( _hPBuffer )
    {
        if(glXGetCurrentContext() == _hGLContext)
            // XXX I don't know if this is right at all
            glXMakeCurrent(_pDisplay, _hPBuffer, 0);
        glXDestroyGLXPbufferSGIX(_pDisplay, _hPBuffer);
        _hPBuffer = 0;
        return true;
    }
#endif

    // [WVB] do we need to call _ReleaseBoundBuffers() too?
    return false;
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::Reset
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::Reset()
* @brief Resets the resolution of the offscreen buffer.
* 
* Causes the buffer to delete itself.  User must call Initialize() again
* before use.
*/ 
bool RenderTexture::Reset(const char *strMode, ...)
{
    _iWidth = 0; _iHeight = 0; 
    _bIsTexture = false; _bIsDepthTexture = false,
    _bHasARBDepthTexture = true;
#ifdef _WIN32
    _eUpdateMode = RT_RENDER_TO_TEXTURE;
#else
    _eUpdateMode = RT_COPY_TO_TEXTURE;
#endif
    _bInitialized = false;
    _iNumAuxBuffers = 0; 
    _bIsBufferBound = false;
    _iCurrentBoundBuffer = 0;
    _iNumDepthBits = 0; _iNumStencilBits = 0;
    _bDoubleBuffered = false;
    _bFloat = false; _bPowerOf2 = true;
    _bRectangle = false; _bMipmap = false; 
    _bShareObjects = false; _bCopyContext = false; 
    _iTextureTarget = GL_NONE; _iTextureID = 0; 
    _iDepthTextureID = 0;
    _pPoorDepthTexture = 0;
    _pixelFormatAttribs.clear();
    _pbufferAttribs.clear();

    if (IsInitialized() && !_Invalidate())
    {
        fprintf(stderr, "RenderTexture::Reset(): failed to invalidate.\n");
        return false;
    }
    
    _iNumColorBits[0] = _iNumColorBits[1] = 
        _iNumColorBits[2] = _iNumColorBits[3] = 0;

#ifdef _WIN32
    _pixelFormatAttribs.push_back(WGL_DRAW_TO_PBUFFER_ARB);
    _pixelFormatAttribs.push_back(true);
    _pixelFormatAttribs.push_back(WGL_SUPPORT_OPENGL_ARB);
    _pixelFormatAttribs.push_back(true);
    
    _pbufferAttribs.push_back(WGL_PBUFFER_LARGEST_ARB);
    _pbufferAttribs.push_back(true);
#elif defined( __APPLE__ )
#else
    _pbufferAttribs.push_back(GLX_RENDER_TYPE_SGIX);
    _pbufferAttribs.push_back(GLX_RGBA_BIT_SGIX);
    _pbufferAttribs.push_back(GLX_DRAWABLE_TYPE_SGIX);
    _pbufferAttribs.push_back(GLX_PBUFFER_BIT_SGIX);
#endif

    va_list args;
    char strBuffer[256];
    va_start(args,strMode);
#if defined _WIN32 && !defined __CYGWIN__
    _vsnprintf( strBuffer, 256, strMode, args );
#else
    vsnprintf( strBuffer, 256, strMode, args );
#endif
    va_end(args);

    _ParseModeString(strBuffer, _pixelFormatAttribs, _pbufferAttribs);

#ifdef _WIN32
    _pixelFormatAttribs.push_back(0);
    _pbufferAttribs.push_back(0);
#else
    _pixelFormatAttribs.push_back(None);
#endif
    return true;
}

//------------------------------------------------------------------------------
// Function         : RenderTexture::Resize
// Description        : 
//------------------------------------------------------------------------------
/**
 * @fn RenderTexture::Resize(int iWidth, int iHeight)
 * @brief Changes the size of the offscreen buffer.
 * 
 * Like Reset() this causes the buffer to delete itself.  
 * But unlike Reset(), this call re-initializes the RenderTexture.
 * Note that Resize() will not work after calling Reset(), or before
 * calling Initialize() the first time.
 */ 
bool RenderTexture::Resize(int iWidth, int iHeight)
{
    if (!_bInitialized) {
        fprintf(stderr, "RenderTexture::Resize(): must Initialize() first.\n");
        return false;
    }
    if (iWidth == _iWidth && iHeight == _iHeight) {
        return true;
    }
    
    // Do same basic work as _Invalidate, but don't reset all our flags
    if (_bIsTexture)
        glDeleteTextures(1, &_iTextureID);
    if (_bIsDepthTexture)
        glDeleteTextures(1, &_iDepthTextureID);
#ifdef _WIN32
    if ( _hPBuffer )
    {
        // Check if we are currently rendering in the pbuffer
        if (wglGetCurrentContext() == _hGLContext)
            wglMakeCurrent(0,0);
        if (!_bCopyContext) 
            wglDeleteContext( _hGLContext);
        wglReleasePbufferDCARBPtr( _hPBuffer, _hDC);
        wglDestroyPbufferARBPtr( _hPBuffer );
        _hPBuffer = 0;
        return true;
    }
#elif defined( __APPLE__ )
#else
    if ( _hPBuffer )
    {
        if(glXGetCurrentContext() == _hGLContext)
            // XXX I don't know if this is right at all
            glXMakeCurrent(_pDisplay, _hPBuffer, 0);
        glXDestroyGLXPbufferSGIX(_pDisplay, _hPBuffer);
        _hPBuffer = 0;
    }
#endif
    else {
        fprintf(stderr, "RenderTexture::Resize(): failed to resize.\n");
        return false;
    }
    _bInitialized = false;
    return Initialize(iWidth, iHeight, _bShareObjects, _bCopyContext);
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::BeginCapture
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::BeginCapture()
* @brief Activates rendering to the RenderTexture.
*/ 
bool RenderTexture::BeginCapture()
{
    if (!_bInitialized)
    {
        fprintf(stderr, 
                "RenderTexture::BeginCapture(): Texture is not initialized!\n");
        return false;
    }
#ifdef _WIN32
    // cache the current context so we can reset it when EndCapture() is called.
    _hPreviousDC      = wglGetCurrentDC();
    if (NULL == _hPreviousDC)
        _wglGetLastError();
    _hPreviousContext = wglGetCurrentContext();
    if (NULL == _hPreviousContext)
        _wglGetLastError();
#elif defined( __APPLE__ )
#else
    _hPreviousContext = glXGetCurrentContext();
    _hPreviousDrawable = glXGetCurrentDrawable();
#endif

    _ReleaseBoundBuffers();

    return _MakeCurrent();
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::EndCapture
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::EndCapture()
* @brief Ends rendering to the RenderTexture.
*/ 
bool RenderTexture::EndCapture()
{    
    if (!_bInitialized)
    {
        fprintf(stderr, 
                "RenderTexture::EndCapture() : Texture is not initialized!\n");
        return false;
    }

    _MaybeCopyBuffer();

#ifdef _WIN32
    // make the previous rendering context current 
    if (FALSE == wglMakeCurrent( _hPreviousDC, _hPreviousContext))
    {
        _wglGetLastError();
        return false;
    }
#elif defined( __APPLE__ )
#else
    if (False == glXMakeCurrent(_pDisplay, _hPreviousDrawable, 
                                _hPreviousContext))
    {
        return false;
    }
#endif

    // rebind the textures to a buffers for RTT
    BindBuffer(_iCurrentBoundBuffer);
    _BindDepthBuffer();

    return true;
}

//---------------------------------------------------------------------------
// Function         : RenderTexture::BeginCapture(RenderTexture*)
// Description        : 
//---------------------------------------------------------------------------
/**
 * @fn RenderTexture::BeginCapture(RenderTexture* other)
 * @brief Ends capture of 'other', begins capture on 'this'
 *
 * When performing a series of operations where you modify one texture after 
 * another, it is more efficient to use this method instead of the equivalent
 * 'EndCapture'/'BeginCapture' pair.  This method switches directly to the 
 * new context rather than changing to the default context, and then to the 
 * new context.
 *
 * RenderTexture doesn't have any mechanism for determining if 
 * 'current' really is currently active, so no error will be thrown 
 * if it is not. 
 */ 
bool RenderTexture::BeginCapture(RenderTexture* current)
{
    bool bContextReset = false;
    
    if (current == this) {
        return true; // no switch necessary
    }
    if (!current) {
        // treat as normal Begin if current is 0.
        return BeginCapture();
    }
    if (!_bInitialized)
    {
        fprintf(stderr, 
            "RenderTexture::BeginCapture(RenderTexture*): Texture is not initialized!\n");
        return false;
    }
    if (!current->_bInitialized)
    {
        fprintf(stderr, 
            "RenderTexture::BeginCapture(RenderTexture): 'current' texture is not initialized!\n");
        return false;
    }
    
    // Sync current pbuffer with its CTT texture if necessary
    current->_MaybeCopyBuffer();

    // pass along the previous context so we can reset it when 
    // EndCapture() is called.
#ifdef _WIN32
    _hPreviousDC      = current->_hPreviousDC;
    if (NULL == _hPreviousDC)
        _wglGetLastError();
    _hPreviousContext = current->_hPreviousContext;
    if (NULL == _hPreviousContext)
        _wglGetLastError();
#elif defined( __APPLE__ )
#else
    _hPreviousContext = current->_hPreviousContext;
    _hPreviousDrawable = current->_hPreviousDrawable;
#endif    

    // Unbind textures before making context current
    if (!_ReleaseBoundBuffers()) 
      return false;

    // Make the pbuffer context current
    if (!_MakeCurrent())
        return false;

    // Rebind buffers of initial RenderTexture
    current->BindBuffer(_iCurrentBoundBuffer);
    current->_BindDepthBuffer();
    
    return true;
}



//---------------------------------------------------------------------------
// Function       : RenderTexture::Bind
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::Bind()
* @brief Binds RGB texture.
*/ 
void RenderTexture::Bind() const 
{ 
    if (_bInitialized && _bIsTexture) 
    {
        glBindTexture(_iTextureTarget, _iTextureID);
    }    
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::BindDepth
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::BindDepth()
* @brief Binds depth texture.
*/ 
void RenderTexture::BindDepth() const 
{ 
    if (_bInitialized && _bIsDepthTexture) 
    {
        glBindTexture(_iTextureTarget, _iDepthTextureID); 
    }
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::BindBuffer
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::BindBuffer()
* @brief Associate the RTT texture id with 'iBuffer' (e.g. WGL_FRONT_LEFT_ARB)
*/ 
bool RenderTexture::BindBuffer( int iBuffer )
{ 
    // Must bind the texture too
    if (_bInitialized && _bIsTexture) 
    {
        glBindTexture(_iTextureTarget, _iTextureID);
        
#ifdef _WIN32
        if (RT_RENDER_TO_TEXTURE == _eUpdateMode && _bIsTexture &&
            (!_bIsBufferBound || _iCurrentBoundBuffer != iBuffer))
        {
            if (FALSE == wglBindTexImageARBPtr(_hPBuffer, iBuffer))
            {
                //  WVB: WGL API considers binding twice to the same buffer
                //  to be an error.  But we don't want to 
                //_wglGetLastError();
                //return false;
                SetLastError(0);
            }
            _bIsBufferBound = true;
            _iCurrentBoundBuffer = iBuffer;
        }
#endif
    }    
    return true;
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::BindBuffer
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_BindDepthBuffer()
* @brief Associate the RTT depth texture id with the depth buffer
*/ 
bool RenderTexture::_BindDepthBuffer() const
{
#ifdef WIN32
    if (_bInitialized && _bIsDepthTexture && 
        RT_RENDER_TO_TEXTURE == _eUpdateMode)
    {
        glBindTexture(_iTextureTarget, _iDepthTextureID);
        if (FALSE == wglBindTexImageARBPtr(_hPBuffer, WGL_DEPTH_COMPONENT_NV))
        {
            _wglGetLastError();
            return false;
        }
    }
#endif
    return true;
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_ParseModeString
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_ParseModeString()
* @brief Parses the user-specified mode string for RenderTexture parameters.
*/ 
void RenderTexture::_ParseModeString(const char *modeString, 
                                     vector<int> &pfAttribs, 
                                     vector<int> &pbAttribs)
{
    if (!modeString || strcmp(modeString, "") == 0)
        return;

      _iNumComponents = 0;
#ifdef _WIN32
    _eUpdateMode = RT_RENDER_TO_TEXTURE;
#else
    _eUpdateMode = RT_COPY_TO_TEXTURE;
#endif
    
    int  iDepthBits = 0;
    bool bHasStencil = false;
    bool bBind2D   = false;
    bool bBindRECT = false;
    bool bBindCUBE = false;
    
    char *mode = strdup(modeString);
    

    vector<string> tokens;
    char *buf = strtok(mode, " ");
    while (buf != NULL)
    {
        tokens.push_back(buf);
        buf = strtok(NULL, " ");
    }

    for (unsigned int i = 0; i < tokens.size(); i++)
    {
        string token = tokens[i];

        KeyVal kv = _GetKeyValuePair(token);
        
        
        if (kv.first == "rgb" && (_iNumComponents <= 1))
        {           
            if (kv.second.find("f") != kv.second.npos)
                _bFloat = true;

            vector<int> bitVec = _ParseBitVector(kv.second);

            if (bitVec.size() < 3) // expand the scalar to a vector
            {
                bitVec.push_back(bitVec[0]);
                bitVec.push_back(bitVec[0]);
            }

#ifdef _WIN32
            pfAttribs.push_back(WGL_RED_BITS_ARB);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(WGL_GREEN_BITS_ARB);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(WGL_BLUE_BITS_ARB);
            pfAttribs.push_back(bitVec[2]);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(AGL_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(AGL_BLUE_SIZE);
            pfAttribs.push_back(bitVec[2]);
#else
# ifndef sgi
            pfAttribs.push_back(GLX_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(GLX_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(GLX_BLUE_SIZE);
            pfAttribs.push_back(bitVec[2]);
# endif
#endif
                  _iNumComponents += 3;
            continue;
        }
            else if (kv.first == "rgb") 
            fprintf(stderr, 
                    "RenderTexture Warning: mistake in components definition "
                    "(rgb + %d).\n", 
                    _iNumComponents);

        
        if (kv.first == "rgba" && (_iNumComponents == 0))
        {
            if (kv.second.find("f") != kv.second.npos)
                _bFloat = true;

            vector<int> bitVec = _ParseBitVector(kv.second);

            if (bitVec.size() < 4) // expand the scalar to a vector
            {
                bitVec.push_back(bitVec[0]);
                bitVec.push_back(bitVec[0]);
                bitVec.push_back(bitVec[0]);
            }

#ifdef _WIN32
            pfAttribs.push_back(WGL_RED_BITS_ARB);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(WGL_GREEN_BITS_ARB);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(WGL_BLUE_BITS_ARB);
            pfAttribs.push_back(bitVec[2]);
            pfAttribs.push_back(WGL_ALPHA_BITS_ARB);
            pfAttribs.push_back(bitVec[3]);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(AGL_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(AGL_BLUE_SIZE);
            pfAttribs.push_back(bitVec[2]);
            pfAttribs.push_back(AGL_ALPHA_SIZE);
            pfAttribs.push_back(bitVec[3]);
#else
# ifndef sgi
            pfAttribs.push_back(GLX_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(GLX_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
            pfAttribs.push_back(GLX_BLUE_SIZE);
            pfAttribs.push_back(bitVec[2]);
            pfAttribs.push_back(GLX_ALPHA_SIZE);
            pfAttribs.push_back(bitVec[3]);
# endif
#endif
                  _iNumComponents = 4;
            continue;
        }
            else if (kv.first == "rgba") 
            fprintf(stderr, 
                    "RenderTexture Warning: mistake in components definition "
                    "(rgba + %d).\n", 
                    _iNumComponents);
        
        if (kv.first == "r" && (_iNumComponents <= 1))
        {
            if (kv.second.find("f") != kv.second.npos)
                _bFloat = true;

            vector<int> bitVec = _ParseBitVector(kv.second);

#ifdef _WIN32
            pfAttribs.push_back(WGL_RED_BITS_ARB);
            pfAttribs.push_back(bitVec[0]);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
#else
            pfAttribs.push_back(GLX_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
#endif
                  _iNumComponents++;
            continue;
        }
            else if (kv.first == "r") 
            fprintf(stderr, 
                    "RenderTexture Warning: mistake in components definition "
                    "(r + %d).\n", 
                    _iNumComponents);

        if (kv.first == "rg" && (_iNumComponents <= 1))
        {
            if (kv.second.find("f") != kv.second.npos)
                _bFloat = true;

            vector<int> bitVec = _ParseBitVector(kv.second);

            if (bitVec.size() < 2) // expand the scalar to a vector
            {
                bitVec.push_back(bitVec[0]);
            }

#ifdef _WIN32
            pfAttribs.push_back(WGL_RED_BITS_ARB);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(WGL_GREEN_BITS_ARB);
            pfAttribs.push_back(bitVec[1]);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(AGL_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
#else
            pfAttribs.push_back(GLX_RED_SIZE);
            pfAttribs.push_back(bitVec[0]);
            pfAttribs.push_back(GLX_GREEN_SIZE);
            pfAttribs.push_back(bitVec[1]);
#endif
                  _iNumComponents += 2;
            continue;
        }
            else if (kv.first == "rg") 
            fprintf(stderr, 
                    "RenderTexture Warning: mistake in components definition "
                    "(rg + %d).\n", 
                    _iNumComponents);

        if (kv.first == "depth")
        {
            if (kv.second == "")
                iDepthBits = 24;
            else
                iDepthBits = strtol(kv.second.c_str(), 0, 10);
            continue;
        }

        if (kv.first == "stencil")
        {
            bHasStencil = true;
#ifdef _WIN32
            pfAttribs.push_back(WGL_STENCIL_BITS_ARB);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_STENCIL_SIZE);
#else
            pfAttribs.push_back(GLX_STENCIL_SIZE);
#endif
            if (kv.second == "")
                pfAttribs.push_back(8);
            else
                pfAttribs.push_back(strtol(kv.second.c_str(), 0, 10));
            continue;
        }

        if (kv.first == "samples")
        {
#ifdef _WIN32
            pfAttribs.push_back(WGL_SAMPLE_BUFFERS_ARB);
            pfAttribs.push_back(1);
            pfAttribs.push_back(WGL_SAMPLES_ARB);
            pfAttribs.push_back(strtol(kv.second.c_str(), 0, 10));
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_SAMPLE_BUFFERS_ARB);
            pfAttribs.push_back(1);
            pfAttribs.push_back(AGL_SAMPLES_ARB);
            pfAttribs.push_back(strtol(kv.second.c_str(), 0, 10));
#else
          pfAttribs.push_back(GL_SAMPLE_BUFFERS_ARB);
          pfAttribs.push_back(1);
          pfAttribs.push_back(GL_SAMPLES_ARB);
            pfAttribs.push_back(strtol(kv.second.c_str(), 0, 10));
#endif
            continue;

        }

        if (kv.first == "doublebuffer" || kv.first == "double")
        {
#ifdef _WIN32
            pfAttribs.push_back(WGL_DOUBLE_BUFFER_ARB);
            pfAttribs.push_back(true);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_DOUBLEBUFFER);
            pfAttribs.push_back(True);
#else
            pfAttribs.push_back(GL_DOUBLEBUFFER);
            pfAttribs.push_back(True);
#endif
            continue;
        }  
        
        if (kv.first == "aux")
        {
#ifdef _WIN32
            pfAttribs.push_back(WGL_AUX_BUFFERS_ARB);
#elif defined( __APPLE__ )
            pfAttribs.push_back(AGL_AUX_BUFFERS);
#else
            pfAttribs.push_back(GL_AUX_BUFFERS);
#endif
            if (kv.second == "")
                pfAttribs.push_back(0);
            else
                pfAttribs.push_back(strtol(kv.second.c_str(), 0, 10));
            continue;
        }
        
        if (token.find("tex") == 0)
        {            
            _bIsTexture = true;
            
            if ((kv.first == "texRECT") && GL_NV_texture_rectangle)
            {
                _bRectangle = true;
                bBindRECT = true;
            }
            else if (kv.first == "texCUBE")
            {
                bBindCUBE = true;
            }
            else
            {
                bBind2D = true;
            }

            continue;
        }

        if (token.find("depthTex") == 0)
        {
            _bIsDepthTexture = true;
            
            if ((kv.first == "depthTexRECT") && GL_NV_texture_rectangle)
            {
                _bRectangle = true;
                bBindRECT = true;
            }
            else if (kv.first == "depthTexCUBE")
            {
                bBindCUBE = true;
            }
            else
            {
                bBind2D = true;
            }

            continue;
        }

        if (kv.first == "mipmap")
        {
            _bMipmap = true;    
            continue;
        }

        if (kv.first == "rtt")
        {
            _eUpdateMode = RT_RENDER_TO_TEXTURE;
            continue;
        }
        
        if (kv.first == "ctt")
        {
            _eUpdateMode = RT_COPY_TO_TEXTURE;
            continue;
        }

        fprintf(stderr, 
                "RenderTexture Error: Unknown pbuffer attribute: %s\n", 
                token.c_str());
    }

    // Processing of some options must be last because of interactions.

    // Check for inconsistent texture targets
    if (_bIsTexture && _bIsDepthTexture && !(bBind2D ^ bBindRECT ^ bBindCUBE))
    {
        fprintf(stderr,
                "RenderTexture Warning: Depth and Color texture targets "
                "should match.\n");
    }

    // Apply default bit format if none specified
#ifdef _WIN32
    if (0 == _iNumComponents)
    {
        pfAttribs.push_back(WGL_RED_BITS_ARB);
        pfAttribs.push_back(8);
        pfAttribs.push_back(WGL_GREEN_BITS_ARB);
        pfAttribs.push_back(8);
        pfAttribs.push_back(WGL_BLUE_BITS_ARB);
        pfAttribs.push_back(8);
        pfAttribs.push_back(WGL_ALPHA_BITS_ARB);
        pfAttribs.push_back(8);
        _iNumComponents = 4;
    }
#endif

    // Depth bits
    if (_bIsDepthTexture && !iDepthBits)
        iDepthBits = 24;

#ifdef _WIN32
    pfAttribs.push_back(WGL_DEPTH_BITS_ARB);
#elif defined( __APPLE__ )
    pfAttribs.push_back(AGL_DEPTH_SIZE);
#else
    pfAttribs.push_back(GLX_DEPTH_SIZE);
#endif
    pfAttribs.push_back(iDepthBits); // default
    
    if (!bHasStencil)
    {
#ifdef _WIN32
        pfAttribs.push_back(WGL_STENCIL_BITS_ARB);
        pfAttribs.push_back(0);
#elif defined( __APPLE__ )
        pfAttribs.push_back(AGL_STENCIL_SIZE);
        pfAttribs.push_back(0);
#else
        pfAttribs.push_back(GLX_STENCIL_SIZE);
        pfAttribs.push_back(0);
#endif

    }
    if (_iNumComponents < 4)
    {
        // Can't do this right now -- on NVIDIA drivers, currently get 
        // a non-functioning pbuffer if ALPHA_BITS=0 and 
        // WGL_BIND_TO_TEXTURE_RGB_ARB=true
        
        //pfAttribs.push_back(WGL_ALPHA_BITS_ARB); 
        //pfAttribs.push_back(0);
    }

#ifdef _WIN32
    if (!WGL_NV_render_depth_texture && _bIsDepthTexture && (RT_RENDER_TO_TEXTURE == _eUpdateMode))
    {
#if defined(DEBUG) || defined(_DEBUG)
        fprintf(stderr, "RenderTexture Warning: No support found for "
                "render to depth texture.\n");
#endif
        _bIsDepthTexture = false;
    }
#endif
    
    if ((_bIsTexture || _bIsDepthTexture) && 
        (RT_RENDER_TO_TEXTURE == _eUpdateMode))
    {
#ifdef _WIN32                   
        if (bBindRECT)
        {
            pbAttribs.push_back(WGL_TEXTURE_TARGET_ARB);
            pbAttribs.push_back(WGL_TEXTURE_RECTANGLE_NV);
        }
        else if (bBindCUBE)
        {
            pbAttribs.push_back(WGL_TEXTURE_TARGET_ARB);
            pbAttribs.push_back(WGL_TEXTURE_CUBE_MAP_ARB);
        }
        else if (bBind2D)
        {
            pbAttribs.push_back(WGL_TEXTURE_TARGET_ARB);
            pbAttribs.push_back(WGL_TEXTURE_2D_ARB);
        }
            
        if (_bMipmap)
        {
            pbAttribs.push_back(WGL_MIPMAP_TEXTURE_ARB);
            pbAttribs.push_back(true);
        }

#elif defined(DEBUG) || defined(_DEBUG)
        printf("RenderTexture Error: Render to Texture not "
               "supported in Linux\n");
#endif  
    }

    // Set the pixel type
    if (_bFloat)
    {
#ifdef _WIN32
        if (WGL_NV_float_buffer)
        {
            pfAttribs.push_back(WGL_PIXEL_TYPE_ARB);
            pfAttribs.push_back(WGL_TYPE_RGBA_ARB);

            pfAttribs.push_back(WGL_FLOAT_COMPONENTS_NV);
            pfAttribs.push_back(true);
        }
        else
        {
            pfAttribs.push_back(WGL_PIXEL_TYPE_ARB);
            pfAttribs.push_back(WGL_TYPE_RGBA_FLOAT_ATI);
        }
#elif defined( __APPLE__ )
#else
        if (GL_NV_float_buffer)
        {
            pfAttribs.push_back(GLX_FLOAT_COMPONENTS_NV);
            pfAttribs.push_back(1);
        }
#endif
    }
    else
    {
#ifdef _WIN32
        pfAttribs.push_back(WGL_PIXEL_TYPE_ARB);
        pfAttribs.push_back(WGL_TYPE_RGBA_ARB);
#endif
    }

    // Set up texture binding for render to texture
    if (_bIsTexture && (RT_RENDER_TO_TEXTURE == _eUpdateMode))
    {
        
#ifdef _WIN32
        if (_bFloat)
        {
            if (WGL_NV_float_buffer)
            {
                switch(_iNumComponents)
                {
                case 1:
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RECTANGLE_FLOAT_R_NV);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_FLOAT_R_NV);
                    break;
                case 2:
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RECTANGLE_FLOAT_RG_NV);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_FLOAT_RG_NV);
                    break;
                case 3:
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RECTANGLE_FLOAT_RGB_NV);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_FLOAT_RGB_NV);
                    break;
                case 4:
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RECTANGLE_FLOAT_RGBA_NV);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_FLOAT_RGBA_NV);
                    break;
                default:
                    fprintf(stderr, 
                            "RenderTexture Warning: Bad number of components "
                            "(r=1,rg=2,rgb=3,rgba=4): %d.\n", 
                            _iNumComponents);
                    break;
                }
            }
            else
            {
                if (4 == _iNumComponents)
                {
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RGBA_ARB);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_RGBA_ARB);
                }
                else 
                {
                    // standard ARB_render_texture only supports 3 or 4 channels
                    pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RGB_ARB);
                    pfAttribs.push_back(true);
                    
                    pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                    pbAttribs.push_back(WGL_TEXTURE_RGB_ARB);
                }
            }
            
        } 
        else
        {
            switch(_iNumComponents)
            {
            case 3:
                pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RGB_ARB);
                pfAttribs.push_back(true);
                
                pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                pbAttribs.push_back(WGL_TEXTURE_RGB_ARB);
                break;
            case 4:
                pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RGBA_ARB);
                pfAttribs.push_back(true);
                
                pbAttribs.push_back(WGL_TEXTURE_FORMAT_ARB);
                pbAttribs.push_back(WGL_TEXTURE_RGBA_ARB);
                break;
            default:
                fprintf(stderr, 
                        "RenderTexture Warning: Bad number of components "
                        "(r=1,rg=2,rgb=3,rgba=4): %d.\n", _iNumComponents);
                break;
            }
        }         
#elif defined(DEBUG) || defined(_DEBUG)
        fprintf(stderr, 
                "RenderTexture Error: Render to Texture not supported in "
                "Linux\n");
#endif  
    }
        
    if (_bIsDepthTexture && (RT_RENDER_TO_TEXTURE == _eUpdateMode))
    {  
#ifdef _WIN32
        if (_bRectangle)
        {
            pfAttribs.push_back(WGL_BIND_TO_TEXTURE_RECTANGLE_DEPTH_NV);
            pfAttribs.push_back(true);
        
            pbAttribs.push_back(WGL_DEPTH_TEXTURE_FORMAT_NV);
            pbAttribs.push_back(WGL_TEXTURE_DEPTH_COMPONENT_NV);
        }
        else 
        {
            pfAttribs.push_back(WGL_BIND_TO_TEXTURE_DEPTH_NV);
            pfAttribs.push_back(true);
        
            pbAttribs.push_back(WGL_DEPTH_TEXTURE_FORMAT_NV);
            pbAttribs.push_back(WGL_TEXTURE_DEPTH_COMPONENT_NV);
        }
#elif defined(DEBUG) || defined(_DEBUG)
        printf("RenderTexture Error: Render to Texture not supported in "
               "Linux\n");
#endif 
    }
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_GetKeyValuePair
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_GetKeyValuePair()
* @brief Parses expressions of the form "X=Y" into a pair (X,Y).
*/ 
RenderTexture::KeyVal RenderTexture::_GetKeyValuePair(string token)
{
    string::size_type pos = 0;
    if ((pos = token.find("=")) != token.npos)
    {
        string key = token.substr(0, pos);
        string value = token.substr(pos+1, token.length()-pos+1);
        return KeyVal(key, value);
    }
    else
        return KeyVal(token, "");
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_ParseBitVector
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_ParseBitVector()
* @brief Parses expressions of the form "=r,g,b,a" into a vector: (r,g,b,a)
*/ 
vector<int> RenderTexture::_ParseBitVector(string bitVector)
{
    vector<string> pieces;
    vector<int> bits;

    if (bitVector == "")
    {
        bits.push_back(8);  // if a depth isn't specified, use default 8 bits
        return bits;
    }

    string::size_type pos = 0; 
    string::size_type nextpos = 0;
    do
    { 
        nextpos = bitVector.find_first_of(", \n", pos);
        pieces.push_back(string(bitVector, pos, nextpos - pos)); 
        pos = nextpos+1; 
    } while (nextpos != bitVector.npos );

    for ( vector<string>::iterator it = pieces.begin(); it != pieces.end(); it++)
    {
        bits.push_back(strtol(it->c_str(), 0, 10));
    }
    
    return bits;
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_VerifyExtensions
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_VerifyExtensions()
* @brief Checks that the necessary extensions are available based on RT mode.
*/ 
bool RenderTexture::_VerifyExtensions()
{
#ifdef _WIN32
    if ( !fctPtrInited )
    {
        fctPtrInited = true;
        wglGetExtensionsStringARBProc wglGetExtensionsStringARBPtr = (wglGetExtensionsStringARBProc)wglGetProcAddress( "wglGetExtensionsStringARB" );
        if ( wglGetExtensionsStringARBPtr == 0 )
        {
            PrintExtensionError("WGL_ARB_extensions_string");
            return false;
        }
        string wglExtensionsString = wglGetExtensionsStringARBPtr( wglGetCurrentDC() );
        if ( SGSearchExtensionsString( wglExtensionsString.c_str(), "WGL_ARB_pixel_format" ) )
        {
            wglChoosePixelFormatARBPtr = (wglChoosePixelFormatARBProc)SGLookupFunction("wglChoosePixelFormatARB");
            wglGetPixelFormatAttribivARBPtr = (wglGetPixelFormatAttribivARBProc)SGLookupFunction("wglGetPixelFormatAttribivARB");
        }
        else
        {
            PrintExtensionError("WGL_ARB_pixel_format");
            return false;
        }
        if ( SGSearchExtensionsString( wglExtensionsString.c_str(), "WGL_ARB_pbuffer" ) )
        {
            wglCreatePbufferARBPtr = (wglCreatePbufferARBProc)SGLookupFunction("wglCreatePbufferARB");
            wglGetPbufferDCARBPtr = (wglGetPbufferDCARBProc)SGLookupFunction("wglGetPbufferDCARB");
            wglQueryPbufferARBPtr = (wglQueryPbufferARBProc)SGLookupFunction("wglQueryPbufferARB");
            wglReleasePbufferDCARBPtr = (wglReleasePbufferDCARBProc)SGLookupFunction("wglReleasePbufferDCARB");
            wglDestroyPbufferARBPtr = (wglDestroyPbufferARBProc)SGLookupFunction("wglDestroyPbufferARB");
        }
        else
        {
            PrintExtensionError("WGL_ARB_pbuffer");
            return false;
        }
        if ( SGSearchExtensionsString( wglExtensionsString.c_str(), "WGL_ARB_render_texture" ) )
        {
            wglBindTexImageARBPtr = (wglBindTexImageARBProc)SGLookupFunction("wglBindTexImageARB");
            wglReleaseTexImageARBPtr = (wglReleaseTexImageARBProc)SGLookupFunction("wglReleaseTexImageARB");
        }
        else if ( _bIsTexture )
        {
            PrintExtensionError("WGL_ARB_render_texture");
            return false;
        }
        if (_bRectangle && !SGIsOpenGLExtensionSupported( "GL_NV_texture_rectangle" ))
        {
            PrintExtensionError("GL_NV_texture_rectangle");
            return false;
        }
        if (_bFloat && !(SGIsOpenGLExtensionSupported( "GL_NV_float_buffer" ) || SGSearchExtensionsString( wglExtensionsString.c_str(), "WGL_ATI_pixel_format_float" )))
        {
            PrintExtensionError("GL_NV_float_buffer or GL_ATI_pixel_format_float");
            return false;
        
        }
        if (_bFloat && _bIsTexture && !(SGIsOpenGLExtensionSupported( "GL_NV_float_buffer" ) || SGIsOpenGLExtensionSupported( "GL_ATI_texture_float" )))
        {
            PrintExtensionError("NV_float_buffer or ATI_texture_float");
        }
        if (_bIsDepthTexture && !SGIsOpenGLExtensionSupported( "GL_ARB_depth_texture" ))
        {
            // [Redge]
#if defined(_DEBUG) | defined(DEBUG)
            fprintf(stderr, 
                    "RenderTexture Warning: "
                    "OpenGL extension GL_ARB_depth_texture not available.\n"
                    "         Using glReadPixels() to emulate behavior.\n");
#endif   
            _bHasARBDepthTexture = false;
            //PrintExtensionError("GL_ARB_depth_texture");
            //return false;
            // [/Redge]
        }
        SetLastError(0);
    }
#elif defined( __APPLE__ )
#else
    if (!GLX_SGIX_pbuffer)
    {
        PrintExtensionError("GL_SGIX_pbuffer");
        return false;
    }
    if (!GLX_SGIX_fbconfig)
    {
        PrintExtensionError("GL_SGIX_fbconfig");
        return false;
    }
    if (_bIsDepthTexture && !GL_ARB_depth_texture)
    {
        PrintExtensionError("GL_ARB_depth_texture");
        return false;
    }
    if (_bFloat && _bIsTexture && !GL_NV_float_buffer)
    {
        PrintExtensionError("GL_NV_float_buffer");
        return false;
    }
    if (_eUpdateMode == RT_RENDER_TO_TEXTURE)
    {
        PrintExtensionError("Some GLX render texture extension: FIXME!");
        return false;
    }
#endif
  
    return true;
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_InitializeTextures
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_InitializeTextures()
* @brief Initializes the state of textures used by the RenderTexture.
*/ 
bool RenderTexture::_InitializeTextures()
{
    // Determine the appropriate texture formats and filtering modes.
    if (_bIsTexture || _bIsDepthTexture)
    {
        if (_bRectangle && GL_NV_texture_rectangle)
            _iTextureTarget = GL_TEXTURE_RECTANGLE_NV;
        else
            _iTextureTarget = GL_TEXTURE_2D;
    }

    if (_bIsTexture)
    {
        glGenTextures(1, &_iTextureID);
        glBindTexture(_iTextureTarget, _iTextureID);  
        
        // Use clamp to edge as the default texture wrap mode for all tex
        glTexParameteri(_iTextureTarget, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(_iTextureTarget, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 
        // Use NEAREST as the default texture filtering mode.
        glTexParameteri(_iTextureTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(_iTextureTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);


        if (RT_COPY_TO_TEXTURE == _eUpdateMode)
        {
            GLuint iInternalFormat;
            GLuint iFormat;

            if (_bFloat)
            {                             
                if (_bMipmap)
                {
                    fprintf(stderr, 
                        "RenderTexture Error: mipmapped float textures not "
                        "supported.\n");
                    return false;
                }
            
                switch(_iNumComponents) 
                {
                case 1:
                    if (GL_NV_float_buffer)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_FLOAT_R32_NV : GL_FLOAT_R16_NV;
                    }
                    else if (GL_ATI_texture_float)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_LUMINANCE_FLOAT32_ATI : 
                            GL_LUMINANCE_FLOAT16_ATI;
                    }
                    iFormat = GL_LUMINANCE;
                  break;
                case 2:
                    if (GL_NV_float_buffer)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_FLOAT_RG32_NV : GL_FLOAT_RG16_NV;
                    }
                    else if (GL_ATI_texture_float)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_LUMINANCE_ALPHA_FLOAT32_ATI : 
                            GL_LUMINANCE_ALPHA_FLOAT16_ATI;
                    }
                    iFormat = GL_LUMINANCE_ALPHA;
                  break;
                case 3:
                    if (GL_NV_float_buffer)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_FLOAT_RGB32_NV : GL_FLOAT_RGB16_NV;
                    }
                    else if (GL_ATI_texture_float)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_RGB_FLOAT32_ATI : GL_RGB_FLOAT16_ATI;
                    }
                    iFormat = GL_RGB;
                    break;
                case 4:
                    if (GL_NV_float_buffer)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_FLOAT_RGBA32_NV : GL_FLOAT_RGBA16_NV;
                    }
                    else if (GL_ATI_texture_float)
                    {
                        iInternalFormat = (_iNumColorBits[0] > 16) ? 
                            GL_RGBA_FLOAT32_ATI : GL_RGBA_FLOAT16_ATI;
                    }
                    iFormat = GL_RGBA;
                    break;
                default:
                    printf("RenderTexture Error: "
                           "Invalid number of components: %d\n", 
                           _iNumComponents);
                    return false;
                }
            }
            else // non-float
            {                        
                if (4 == _iNumComponents)
                {
                    iInternalFormat = GL_RGBA8;
                    iFormat = GL_RGBA;
                }
                else 
                {
                    iInternalFormat = GL_RGB8;
                    iFormat = GL_RGB;
                }
            }
        
            // Allocate the texture image (but pass it no data for now).
            glTexImage2D(_iTextureTarget, 0, iInternalFormat, 
                         _iWidth, _iHeight, 0, iFormat, GL_FLOAT, NULL);
        } 
    }
  
    if (_bIsDepthTexture)
    { 
        glGenTextures(1, &_iDepthTextureID);
        glBindTexture(_iTextureTarget, _iDepthTextureID);  
        
        // Use clamp to edge as the default texture wrap mode for all tex
        glTexParameteri(_iTextureTarget, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(_iTextureTarget, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 
        // Use NEAREST as the default texture filtering mode.
        glTexParameteri(_iTextureTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(_iTextureTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
               
        if (RT_COPY_TO_TEXTURE == _eUpdateMode)
        {
            // [Redge]
            if (_bHasARBDepthTexture) 
            {
                // Allocate the texture image (but pass it no data for now).
                glTexImage2D(_iTextureTarget, 0, GL_DEPTH_COMPONENT, 
                             _iWidth, _iHeight, 0, GL_DEPTH_COMPONENT, 
                             GL_FLOAT, NULL);
            } 
            else 
            {
                // allocate memory for depth texture
                // Since this is slow, we warn the user in debug mode. (above)
                _pPoorDepthTexture = new unsigned short[_iWidth * _iHeight];
                glTexImage2D(_iTextureTarget, 0, GL_LUMINANCE16, 
                             _iWidth, _iHeight, 0, GL_LUMINANCE, 
                             GL_UNSIGNED_SHORT, _pPoorDepthTexture);
            }
            // [/Redge]
        }
    }

    return true;
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::_MaybeCopyBuffer
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_MaybeCopyBuffer()
* @brief Does the actual copying for RenderTextures with RT_COPY_TO_TEXTURE
*/ 
void RenderTexture::_MaybeCopyBuffer()
{
#ifdef _WIN32
    if (RT_COPY_TO_TEXTURE == _eUpdateMode)
    {
        if (_bIsTexture)
        {
            glBindTexture(_iTextureTarget, _iTextureID);
            glCopyTexSubImage2D(_iTextureTarget, 
                                0, 0, 0, 0, 0, _iWidth, _iHeight);
        }
        if (_bIsDepthTexture)
        {
            glBindTexture(_iTextureTarget, _iDepthTextureID);
            // HOW TO COPY DEPTH TEXTURE??? Supposedly this just magically works...
            // [Redge]
            if (_bHasARBDepthTexture) 
            {
                glCopyTexSubImage2D(_iTextureTarget, 0, 0, 0, 0, 0, 
                                    _iWidth, _iHeight);
            } 
            else 
            {
                // no 'real' depth texture available, so behavior has to be emulated
                // using glReadPixels (beware, this is (naturally) slow ...)
                glReadPixels(0, 0, _iWidth, _iHeight, GL_DEPTH_COMPONENT, 
                             GL_UNSIGNED_SHORT, _pPoorDepthTexture);
                glTexImage2D(_iTextureTarget, 0, GL_LUMINANCE16,
                             _iWidth, _iHeight, 0, GL_LUMINANCE, 
                             GL_UNSIGNED_SHORT, _pPoorDepthTexture);
            }
            // [/Redge]
        }
    }
    
#else
    if (_bIsTexture)
    {
      glBindTexture(_iTextureTarget, _iTextureID);
      glCopyTexSubImage2D(_iTextureTarget, 0, 0, 0, 0, 0, _iWidth, _iHeight);
    }
    if (_bIsDepthTexture)
    {
      glBindTexture(_iTextureTarget, _iDepthTextureID);
      assert(_bHasARBDepthTexture);
      glCopyTexSubImage2D(_iTextureTarget, 0, 0, 0, 0, 0, _iWidth, _iHeight);
    }
#endif

}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_ReleaseBoundBuffers
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_ReleaseBoundBuffers()
* @brief Releases buffer bindings on RenderTextures with RT_RENDER_TO_TEXTURE
*/ 
bool RenderTexture::_ReleaseBoundBuffers()
{
#ifdef _WIN32
    if (_bIsTexture && RT_RENDER_TO_TEXTURE == _eUpdateMode)
    {
        glBindTexture(_iTextureTarget, _iTextureID);
        
        // release the pbuffer from the render texture object
        if (0 != _iCurrentBoundBuffer && _bIsBufferBound)
        {
            if (FALSE == wglReleaseTexImageARBPtr(_hPBuffer, _iCurrentBoundBuffer))
            {
                _wglGetLastError();
                return false;
            }
            _bIsBufferBound = false;
        }
    }
    
    if (_bIsDepthTexture && RT_RENDER_TO_TEXTURE == _eUpdateMode)
    {
        glBindTexture(_iTextureTarget, _iDepthTextureID);
        
        // release the pbuffer from the render texture object
        if (FALSE == wglReleaseTexImageARBPtr(_hPBuffer, WGL_DEPTH_COMPONENT_NV))
        {
            _wglGetLastError();
            return false;
        }
    }
    
#else
    // textures can't be bound in Linux
#endif
    return true;
}

//---------------------------------------------------------------------------
// Function       : RenderTexture::_MakeCurrent
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::_MakeCurrent()
* @brief Makes the RenderTexture's context current
*/ 

bool RenderTexture::_MakeCurrent() 
{
#ifdef _WIN32
    // make the pbuffer's rendering context current.
    if (FALSE == wglMakeCurrent( _hDC, _hGLContext))
    {
        _wglGetLastError();
        return false;
    }
#elif defined( __APPLE__ )
#else
    if (false == glXMakeCurrent(_pDisplay, _hPBuffer, _hGLContext)) 
    {
        return false;
    }
#endif

    return true;
}

/////////////////////////////////////////////////////////////////////////////
//
// Begin Deprecated Interface
//
/////////////////////////////////////////////////////////////////////////////

//---------------------------------------------------------------------------
// Function      : RenderTexture::RenderTexture
// Description     : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::RenderTexture()
* @brief Constructor.
*/ 
RenderTexture::RenderTexture(int width, int height,
                               bool bIsTexture /* = true */,
                               bool bIsDepthTexture /* = false */)
:   _iWidth(width), 
    _iHeight(height), 
    _bIsTexture(bIsTexture),
    _bIsDepthTexture(bIsDepthTexture),
    _bHasARBDepthTexture(true),            // [Redge]
    _eUpdateMode(RT_RENDER_TO_TEXTURE),
    _bInitialized(false),
    _iNumAuxBuffers(0),
    _iCurrentBoundBuffer(0),
    _iNumDepthBits(0),
    _iNumStencilBits(0),
    _bFloat(false),
    _bDoubleBuffered(false),
    _bPowerOf2(true),
    _bRectangle(false),
    _bMipmap(false),
    _bShareObjects(false),
    _bCopyContext(false),
#ifdef _WIN32
    _hDC(NULL), 
    _hGLContext(NULL), 
    _hPBuffer(NULL),
    _hPreviousDC(0),
    _hPreviousContext(0),
#elif defined( __APPLE__ )
#else
    _pDisplay(NULL),
    _hGLContext(NULL),
    _hPBuffer(0),
    _hPreviousContext(0),
    _hPreviousDrawable(0),
#endif
    _iTextureTarget(GL_NONE),
    _iTextureID(0),
    _iDepthTextureID(0),
    _pPoorDepthTexture(0) // [Redge]
{
    assert(width > 0 && height > 0);
#if defined DEBUG || defined _DEBUG
    fprintf(stderr, 
            "RenderTexture Warning: Deprecated Contructor interface used.\n");
#endif
    
    _iNumColorBits[0] = _iNumColorBits[1] = 
        _iNumColorBits[2] = _iNumColorBits[3] = 0;
    _bPowerOf2 = IsPowerOfTwo(width) && IsPowerOfTwo(height);
}

//------------------------------------------------------------------------------
// Function       : RenderTexture::Initialize
// Description        : 
//------------------------------------------------------------------------------
/**
* @fn RenderTexture::Initialize(bool bShare, bool bDepth, bool bStencil, bool bMipmap, unsigned int iRBits, unsigned int iGBits, unsigned int iBBits, unsigned int iABits);
* @brief Initializes the RenderTexture, sharing display lists and textures if specified.
* 
* This function actually does the creation of the p-buffer.  It can only be called 
* once a GL context has already been created.  Note that if the texture is not
* power of two dimensioned, or has more than 8 bits per channel, enabling mipmapping
* will cause an error.
*/ 
bool RenderTexture::Initialize(bool         bShare       /* = true */, 
                                bool         bDepth       /* = false */, 
                                bool         bStencil     /* = false */, 
                                bool         bMipmap      /* = false */, 
                                bool         bAnisoFilter /* = false */,
                                unsigned int iRBits       /* = 8 */, 
                                unsigned int iGBits       /* = 8 */, 
                                unsigned int iBBits       /* = 8 */, 
                                unsigned int iABits       /* = 8 */,
                                UpdateMode   updateMode   /* = RT_RENDER_TO_TEXTURE */)
{   
    if (0 == _iWidth || 0 == _iHeight)
        return false;

#if defined DEBUG || defined _DEBUG
    fprintf(stderr, 
            "RenderTexture Warning: Deprecated Initialize() interface used.\n");
#endif   

    // create a mode string.
    string mode = "";
    if (bDepth)
        mode.append("depth ");
    if (bStencil)
        mode.append("stencil ");
    if (bMipmap)
        mode.append("mipmap ");
    if (iRBits + iGBits + iBBits + iABits > 0)
    {
        if (iRBits > 0)
            mode.append("r");
        if (iGBits > 0)
            mode.append("g");
        if (iBBits > 0)
            mode.append("b");
        if (iABits > 0)
            mode.append("a");
        mode.append("=");
        char bitVector[100];
        sprintf(bitVector,
            "%d%s,%d%s,%d%s,%d%s",
            iRBits, (iRBits >= 16) ? "f" : "",
            iGBits, (iGBits >= 16) ? "f" : "",
            iBBits, (iBBits >= 16) ? "f" : "",
            iABits, (iABits >= 16) ? "f" : "");
        mode.append(bitVector);
        mode.append(" ");
    }
    if (_bIsTexture)
    {
        if (GL_NV_texture_rectangle && 
            ((!IsPowerOfTwo(_iWidth) || !IsPowerOfTwo(_iHeight))
              || iRBits >= 16 || iGBits > 16 || iBBits > 16 || iABits >= 16))
            mode.append("texRECT ");
        else
            mode.append("tex2D ");
    }
    if (_bIsDepthTexture)
    {
        if (GL_NV_texture_rectangle && 
            ((!IsPowerOfTwo(_iWidth) || !IsPowerOfTwo(_iHeight))
              || iRBits >= 16 || iGBits > 16 || iBBits > 16 || iABits >= 16))
            mode.append("texRECT ");
        else
            mode.append("tex2D ");
    }
    if (RT_COPY_TO_TEXTURE == updateMode)
        mode.append("ctt");

    _pixelFormatAttribs.clear();
    _pbufferAttribs.clear();

#ifdef _WIN32
    _pixelFormatAttribs.push_back(WGL_DRAW_TO_PBUFFER_ARB);
    _pixelFormatAttribs.push_back(true);
    _pixelFormatAttribs.push_back(WGL_SUPPORT_OPENGL_ARB);
    _pixelFormatAttribs.push_back(true);
    
    _pbufferAttribs.push_back(WGL_PBUFFER_LARGEST_ARB);
    _pbufferAttribs.push_back(true);
#elif defined( __APPLE__ )
#else
    _pixelFormatAttribs.push_back(GLX_RENDER_TYPE_SGIX);
    _pixelFormatAttribs.push_back(GLX_RGBA_BIT_SGIX);
    _pixelFormatAttribs.push_back(GLX_DRAWABLE_TYPE_SGIX);
    _pixelFormatAttribs.push_back(GLX_PBUFFER_BIT_SGIX);
#endif

    _ParseModeString(mode.c_str(), _pixelFormatAttribs, _pbufferAttribs);

#ifdef _WIN32
    _pixelFormatAttribs.push_back(0);
    _pbufferAttribs.push_back(0);
#else
    _pixelFormatAttribs.push_back(None);
#endif

    Initialize(_iWidth, _iHeight, bShare);
    
    return true;
}


//---------------------------------------------------------------------------
// Function       : RenderTexture::Reset
// Description        : 
//---------------------------------------------------------------------------
/**
* @fn RenderTexture::Reset(int iWidth, int iHeight, unsigned int iMode, bool bIsTexture, bool bIsDepthTexture)
* @brief Resets the resolution of the offscreen buffer.
* 
* Causes the buffer to delete itself.  User must call Initialize() again
* before use.
*/ 
bool RenderTexture::Reset(int iWidth, int iHeight)
{
    fprintf(stderr, 
            "RenderTexture Warning: Deprecated Reset() interface used.\n");

    if (!_Invalidate())
    {
        fprintf(stderr, "RenderTexture::Reset(): failed to invalidate.\n");
        return false;
    }
    _iWidth     = iWidth;
    _iHeight    = iHeight;
    
    return true;
}

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