src/libprojectM/Renderer/FBO.cpp - vendor/opensource/projectM - Git at Google

 /**
  * projectM -- Milkdrop-esque visualisation SDK
  * Copyright (C)2003-2004 projectM Team
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  * See 'LICENSE.txt' included within this release
  *
  */
 /**
  * $Id: FBO.c,v 1.1.1.1 2005/12/23 18:05:00 psperl Exp $
  *
  * Render this methods
  */
 #include <stdio.h>
 #include <string.h>
 //#include <GL/gl.h>
 #include <iostream>
 #include "Common.hpp"
 #include "FBO.hpp"


 RenderTarget::~RenderTarget()
 {
   glDeleteTextures (1, &this->textureID[0]);

 #ifdef USE_FBO
   if (useFBO)
   {
     glDeleteTextures (1, &this->textureID[1]);
     glDeleteRenderbuffers (1,  &this->depthb[0]);
     glDeleteFramebuffers (1, &this->fbuffer[0]);
     if (renderToTexture)
     {
       glDeleteTextures (1, &this->textureID[2]);
       glDeleteRenderbuffers (1,  &this->depthb[1]);
       glDeleteFramebuffers (1, &this->fbuffer[1]);
     }
   }
 #endif
 }

 GLuint RenderTarget::initRenderToTexture()
 {
 #ifdef USE_FBO
   if (this->useFBO==1)
   {
     this->renderToTexture=1;

     GLuint   fb2, depth_rb2;

     glGenFramebuffers (1, &fb2);
     glBindFramebuffer (GL_FRAMEBUFFER, fb2);
     glGenRenderbuffers (1, &depth_rb2);
     glBindRenderbuffer (GL_RENDERBUFFER, depth_rb2);

     glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, this->texsize,this->texsize );
     glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_rb2);
     this->fbuffer[1] = fb2;
     this->depthb[1]=  depth_rb2;
     glGenTextures (1, &this->textureID[2]);
     glBindTexture (GL_TEXTURE_2D, this->textureID[2]);
     glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 #ifdef USE_GLES1
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 #else
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 #endif
     glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, this->textureID[2], 0);
     return this->textureID[2];
   }
 #endif
   return -1;
 }

 /** Creates new pbuffers */
 RenderTarget::RenderTarget (int texsize, int width, int height)
   : useFBO (false)
 {
   int mindim = 0;
   int origtexsize = 0;

   this->renderToTexture = 0;
   this->texsize = texsize;

 #ifdef USE_FBO
   // Forcibly disable FBO if user requested it but the video card / driver lacks
   // the appropraite frame buffer extension.

 #ifdef USE_GLES1
   /*
    * FBO support is never part of GLES1 core; check for extension.
    */
   useFBO = !!strstr ((char const *) glGetString (GL_EXTENSIONS),
                      "GL_OES_framebuffer_object");
 #else
   /*
    * If GL 3.0 or later is in scope, then framebuffer object support is present
    * by default, and we just use the user's preference.
    */
   {
     long        majorvers;
     char const  *glvers;
     char        *endptr;

     glvers = glGetString (GL_VERSION);
     majorvers = strtol (glvers, &endptr, 10);
     if (endptr == glvers  ||  *endptr != '.') {
       /*  Unparseable version number; force extension check.  */
       majorvers = 0;
     }
     if (majorvers < 3) {
       /*  GL 3.0 not in scope; check for FBO support by extension.  */
       useFBO = !!strstr ((char const *) glGetString (GL_EXTENSIONS),
                          "GL_EXT_framebuffer_object");
     }
   }
 #endif  /*  USE_GLES1  */

   if (useFBO)
   {
     GLuint   fb,  depth_rb, rgba_tex,  other_tex;
     glGenFramebuffers (1, &fb);
     glBindFramebuffer (GL_FRAMEBUFFER, fb);

     glGenRenderbuffers (1, &depth_rb);
     glBindRenderbuffer (GL_RENDERBUFFER, depth_rb);
     glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, this->texsize,this->texsize );
     glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_rb);
     this->fbuffer[0] = fb;
     this->depthb[0]=  depth_rb;

     glGenTextures (1, &other_tex);
     glBindTexture (GL_TEXTURE_2D,other_tex);
     glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
     //glGenerateMipmap (GL_TEXTURE_2D);
 #ifdef USE_GLES1
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 #else
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 #endif


     glGenTextures (1, &rgba_tex);
     glBindTexture (GL_TEXTURE_2D, rgba_tex);
     glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
     //glGenerateMipmap (GL_TEXTURE_2D);
 #ifdef USE_GLES1
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 #else
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 #endif


     glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rgba_tex, 0);
     this->textureID[0] = rgba_tex;
     this->textureID[1] = other_tex;

     GLenum status = glCheckFramebufferStatus (GL_FRAMEBUFFER);

     glBindFramebuffer (GL_FRAMEBUFFER, 0);

     if (status == GL_FRAMEBUFFER_COMPLETE) {
       return;
     }
     std::cerr << "[projecM] warning: FBO support not detected. Using fallback." << std::endl;
   }
 #endif  /*  USE_FBO  */

   // Can reach here via two code paths:
   // (1) useFBO was set to false externally by cmake / system setting / etc.
   // (2) useFBO was true but forced to false as it failed to pass all the GLU extension checks.

   /** Fallback pbuffer creation via teximage hack */
   /** Check the texture size against the viewport size */
   /** If the viewport is smaller, then we'll need to scale the texture size down */
   /** If the viewport is larger, scale it up */
   mindim = width < height ? width : height;
   origtexsize = this->texsize;
   this->texsize = nearestPower2 (mindim, SCALE_MINIFY);
   glGenTextures (1, &this->textureID[0]);

   glBindTexture (GL_TEXTURE_2D, this->textureID[0]);
   //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

   glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

   glTexImage2D (GL_TEXTURE_2D,
                 0,
                 GL_RGBA,
                 this->texsize, this->texsize,
                 0,
                 GL_RGBA,
                 GL_UNSIGNED_BYTE,
                 NULL);

   return;
 }

 void
 RenderTarget::fallbackRescale (int width, int height)
 {
   int mindim = width < height ? width : height;
   int origtexsize = this->texsize;

   this->texsize = nearestPower2 (mindim, SCALE_MINIFY);

   if (origtexsize == texsize)
     return;

   /* Create the texture that will be bound to the render this */
   /*

   if (this->texsize != origtexsize) {
     glDeleteTextures (1, &this->textureID[0]);
   }
   */

   glGenTextures (1, &this->textureID[0]);

   glBindTexture (GL_TEXTURE_2D, this->textureID[0]);
   //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

   glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

   glTexImage2D (GL_TEXTURE_2D,
                 0,
                 GL_RGBA,
                 this->texsize, this->texsize,
                 0,
                 GL_RGBA,
                 GL_UNSIGNED_BYTE,
                 NULL);
 }

 /** Destroys the pbuffer */

 /** Locks the pbuffer */
 void
 RenderTarget::lock()
 {
 #ifdef USE_FBO
   if (this->useFBO)
   {
     glBindFramebuffer (GL_FRAMEBUFFER, this->fbuffer[0]);
   }
 #endif
 }

 /** Unlocks the pbuffer */
 void
 RenderTarget::unlock()
 {
 #ifdef USE_FBO
   if (this->useFBO)
   {
     glBindTexture (GL_TEXTURE_2D, this->textureID[1]);
     glCopyTexSubImage2D (GL_TEXTURE_2D,
                          0, 0, 0, 0, 0,
                          this->texsize, this->texsize);
     glBindFramebuffer (GL_FRAMEBUFFER, 0);
     return;
   }
 #endif
   /** Fallback texture path */

   glBindTexture (GL_TEXTURE_2D, this->textureID[0]);

   glCopyTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, 0, 0, this->texsize, this->texsize);
 }

 /**
  * Calculates the nearest power of two to the given number using the
  * appropriate rule
  */
 int
 RenderTarget::nearestPower2 (int value, TextureScale scaleRule)
 {
   int x = value;
   int power = 0;

   while ((x & 0x01) != 1) {
     x >>= 1;
   }

   if (x == 1) {
     return value;
   } else {
     x = value;
     while (x != 0) {
       x >>= 1;
       power++;
     }
     switch (scaleRule) {
     case SCALE_NEAREST:
       if (((1 << power) - value) <= (value - (1 << (power - 1)))) {
         return 1 << power;
       } else {
         return 1 << (power - 1);
       }
     case SCALE_MAGNIFY:
       return 1 << power;
     case SCALE_MINIFY:
       return 1 << (power - 1);
     default:
       break;
     }
   }
   return 0;
 }
	/**
	* projectM -- Milkdrop-esque visualisation SDK
	* Copyright (C)2003-2004 projectM Team
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	* See 'LICENSE.txt' included within this release
	*
	*/
	/**
	* $Id: FBO.c,v 1.1.1.1 2005/12/23 18:05:00 psperl Exp $
	*
	* Render this methods
	*/
	#include <stdio.h>
	#include <string.h>
	//#include <GL/gl.h>
	#include <iostream>
	#include "Common.hpp"
	#include "FBO.hpp"



	RenderTarget::~RenderTarget()
	{
	glDeleteTextures (1, &this->textureID[0]);

	#ifdef USE_FBO
	if (useFBO)
	{
	glDeleteTextures (1, &this->textureID[1]);
	glDeleteRenderbuffers (1, &this->depthb[0]);
	glDeleteFramebuffers (1, &this->fbuffer[0]);
	if (renderToTexture)
	{
	glDeleteTextures (1, &this->textureID[2]);
	glDeleteRenderbuffers (1, &this->depthb[1]);
	glDeleteFramebuffers (1, &this->fbuffer[1]);
	}
	}
	#endif
	}

	GLuint RenderTarget::initRenderToTexture()
	{
	#ifdef USE_FBO
	if (this->useFBO==1)
	{
	this->renderToTexture=1;

	GLuint fb2, depth_rb2;

	glGenFramebuffers (1, &fb2);
	glBindFramebuffer (GL_FRAMEBUFFER, fb2);
	glGenRenderbuffers (1, &depth_rb2);
	glBindRenderbuffer (GL_RENDERBUFFER, depth_rb2);

	glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, this->texsize,this->texsize );
	glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_rb2);
	this->fbuffer[1] = fb2;
	this->depthb[1]= depth_rb2;
	glGenTextures (1, &this->textureID[2]);
	glBindTexture (GL_TEXTURE_2D, this->textureID[2]);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	#ifdef USE_GLES1
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	#else
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	#endif
	glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, this->textureID[2], 0);
	return this->textureID[2];
	}
	#endif
	return -1;
	}

	/** Creates new pbuffers */
	RenderTarget::RenderTarget (int texsize, int width, int height)
	: useFBO (false)
	{
	int mindim = 0;
	int origtexsize = 0;

	this->renderToTexture = 0;
	this->texsize = texsize;

	#ifdef USE_FBO
	// Forcibly disable FBO if user requested it but the video card / driver lacks
	// the appropraite frame buffer extension.

	#ifdef USE_GLES1
	/*
	* FBO support is never part of GLES1 core; check for extension.
	*/
	useFBO = !!strstr ((char const *) glGetString (GL_EXTENSIONS),
	"GL_OES_framebuffer_object");
	#else
	/*
	* If GL 3.0 or later is in scope, then framebuffer object support is present
	* by default, and we just use the user's preference.
	*/
	{
	long majorvers;
	char const *glvers;
	char *endptr;

	glvers = glGetString (GL_VERSION);
	majorvers = strtol (glvers, &endptr, 10);
	if (endptr == glvers \|\| *endptr != '.') {
	/* Unparseable version number; force extension check. */
	majorvers = 0;
	}
	if (majorvers < 3) {
	/* GL 3.0 not in scope; check for FBO support by extension. */
	useFBO = !!strstr ((char const *) glGetString (GL_EXTENSIONS),
	"GL_EXT_framebuffer_object");
	}
	}
	#endif /* USE_GLES1 */

	if (useFBO)
	{
	GLuint fb, depth_rb, rgba_tex, other_tex;
	glGenFramebuffers (1, &fb);
	glBindFramebuffer (GL_FRAMEBUFFER, fb);

	glGenRenderbuffers (1, &depth_rb);
	glBindRenderbuffer (GL_RENDERBUFFER, depth_rb);
	glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, this->texsize,this->texsize );
	glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_rb);
	this->fbuffer[0] = fb;
	this->depthb[0]= depth_rb;

	glGenTextures (1, &other_tex);
	glBindTexture (GL_TEXTURE_2D,other_tex);
	glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	//glGenerateMipmap (GL_TEXTURE_2D);
	#ifdef USE_GLES1
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	#else
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	#endif



	glGenTextures (1, &rgba_tex);
	glBindTexture (GL_TEXTURE_2D, rgba_tex);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, texsize, texsize, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	//glGenerateMipmap (GL_TEXTURE_2D);
	#ifdef USE_GLES1
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	#else
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	#endif



	glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rgba_tex, 0);
	this->textureID[0] = rgba_tex;
	this->textureID[1] = other_tex;

	GLenum status = glCheckFramebufferStatus (GL_FRAMEBUFFER);

	glBindFramebuffer (GL_FRAMEBUFFER, 0);

	if (status == GL_FRAMEBUFFER_COMPLETE) {
	return;
	}
	std::cerr << "[projecM] warning: FBO support not detected. Using fallback." << std::endl;
	}
	#endif /* USE_FBO */

	// Can reach here via two code paths:
	// (1) useFBO was set to false externally by cmake / system setting / etc.
	// (2) useFBO was true but forced to false as it failed to pass all the GLU extension checks.

	/** Fallback pbuffer creation via teximage hack */
	/** Check the texture size against the viewport size */
	/** If the viewport is smaller, then we'll need to scale the texture size down */
	/** If the viewport is larger, scale it up */
	mindim = width < height ? width : height;
	origtexsize = this->texsize;
	this->texsize = nearestPower2 (mindim, SCALE_MINIFY);
	glGenTextures (1, &this->textureID[0]);

	glBindTexture (GL_TEXTURE_2D, this->textureID[0]);
	//glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	//glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	glTexImage2D (GL_TEXTURE_2D,
	0,
	GL_RGBA,
	this->texsize, this->texsize,
	0,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	NULL);

	return;
	}

	void
	RenderTarget::fallbackRescale (int width, int height)
	{
	int mindim = width < height ? width : height;
	int origtexsize = this->texsize;

	this->texsize = nearestPower2 (mindim, SCALE_MINIFY);

	if (origtexsize == texsize)
	return;

	/* Create the texture that will be bound to the render this */
	/*

	if (this->texsize != origtexsize) {
	glDeleteTextures (1, &this->textureID[0]);
	}
	*/

	glGenTextures (1, &this->textureID[0]);

	glBindTexture (GL_TEXTURE_2D, this->textureID[0]);
	//glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	//glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	glTexImage2D (GL_TEXTURE_2D,
	0,
	GL_RGBA,
	this->texsize, this->texsize,
	0,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	NULL);
	}

	/** Destroys the pbuffer */

	/** Locks the pbuffer */
	void
	RenderTarget::lock()
	{
	#ifdef USE_FBO
	if (this->useFBO)
	{
	glBindFramebuffer (GL_FRAMEBUFFER, this->fbuffer[0]);
	}
	#endif
	}

	/** Unlocks the pbuffer */
	void
	RenderTarget::unlock()
	{
	#ifdef USE_FBO
	if (this->useFBO)
	{
	glBindTexture (GL_TEXTURE_2D, this->textureID[1]);
	glCopyTexSubImage2D (GL_TEXTURE_2D,
	0, 0, 0, 0, 0,
	this->texsize, this->texsize);
	glBindFramebuffer (GL_FRAMEBUFFER, 0);
	return;
	}
	#endif
	/** Fallback texture path */

	glBindTexture (GL_TEXTURE_2D, this->textureID[0]);

	glCopyTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, 0, 0, this->texsize, this->texsize);
	}

	/**
	* Calculates the nearest power of two to the given number using the
	* appropriate rule
	*/
	int
	RenderTarget::nearestPower2 (int value, TextureScale scaleRule)
	{
	int x = value;
	int power = 0;

	while ((x & 0x01) != 1) {
	x >>= 1;
	}

	if (x == 1) {
	return value;
	} else {
	x = value;
	while (x != 0) {
	x >>= 1;
	power++;
	}
	switch (scaleRule) {
	case SCALE_NEAREST:
	if (((1 << power) - value) <= (value - (1 << (power - 1)))) {
	return 1 << power;
	} else {
	return 1 << (power - 1);
	}
	case SCALE_MAGNIFY:
	return 1 << power;
	case SCALE_MINIFY:
	return 1 << (power - 1);
	default:
	break;
	}
	}
	return 0;
	}