GLFrameBufferObject.cpp

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////////////////////////////////////////////////////////////////////////////////
//    Scorched3D (c) 2000-2009
//
//    This file is part of Scorched3D.
//
//    Scorched3D is free software; you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation; either version 2 of the License, or
//    (at your option) any later version.
//
//    Scorched3D 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 General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with Scorched3D; if not, write to the Free Software
//    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
////////////////////////////////////////////////////////////////////////////////

#include <GLEXT/GLFrameBufferObject.h>
#include <GLEXT/GLStateExtension.h>
#include <common/DefinesAssert.h>

GLFrameBufferObject::GLFrameBufferObject() : 
        frameBufferObject_(0), depthBufferObject_(0),
        texture_(0), bound_(false)
{
}

GLFrameBufferObject::~GLFrameBufferObject()
{
        destroy();
}

bool GLFrameBufferObject::create(GLTexture &texture, bool withDepth)
{
        if (!GLStateExtension::hasFBO()) {
                S3D::dialogExit("GLFrameBufferObject", "NO FBO");
        }

        texture_ = &texture;

        // create and bind depth buffer if requested
        if (withDepth) {
                glGenRenderbuffersEXT(1, &depthBufferObject_);
                glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthBufferObject_);
                glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
                        texture.getWidth(), texture.getHeight());
        }

        // create and bind FBO
        glGenFramebuffersEXT(1, &frameBufferObject_);
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, frameBufferObject_);
        glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                GL_TEXTURE_2D, texture.getTexName(), 0);

        // attach depth buffer if requested
        if (withDepth) {
                glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
                        GL_RENDERBUFFER_EXT, depthBufferObject_);
        }

        GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
        if(status != GL_FRAMEBUFFER_COMPLETE_EXT) {
                destroy();
                S3D::dialogExit("GLFrameBufferObject", "FBO Init");
        }

        // unbind for now
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
        glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

        return true;
}

void GLFrameBufferObject::destroy()
{
        if (frameBufferObject_) glDeleteFramebuffersEXT(1, &frameBufferObject_);
        if (depthBufferObject_) glDeleteRenderbuffersEXT(1, &depthBufferObject_);

        frameBufferObject_ = 0;
        depthBufferObject_ = 0;
}

void GLFrameBufferObject::bind()
{
        if (bound_) S3D::dialogExit("GLFrameBufferObject", "already bound");

        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, frameBufferObject_);
        glPushAttrib(GL_VIEWPORT_BIT);
        glViewport(0, 0, texture_->getWidth(), texture_->getHeight());
        bound_ = true;
}

void GLFrameBufferObject::unBind()
{
        if (!bound_) S3D::dialogExit("GLFrameBufferObject", "not bound");

        glPopAttrib();
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
        bound_ = false;
}

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