framebuffer.h

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/*
 * framebuffer.h
 *
 * Copyright (C) 2010  Thomas A. Vaughan
 * All rights reserved.
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THOMAS A. VAUGHAN ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THOMAS A. VAUGHAN BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Simple framebuffer object (for offscreen drawing)
 */

#ifndef WAVE_GLUT_EFFECTS_FRAMEBUFFER_H__
#define WAVE_GLUT_EFFECTS_FRAMEBUFFER_H__


// includes --------------------------------------------------------------------
#include "wave-glut/renderable.h"
#include "wave-image/wave-image.h"


namespace glut {


/// \ingroup glut_effects
/*@{*/



/// provides a framebuffer of fixed size for offscreen rendering.
/// To use:
///  - create the framebuffer with the set width and height
///  - create a texture of the same width and height
///  - call Framebuffer::setupForRendering() with the texture.  The perspective
///     matrix will be tweaked to account for the new aspect ratio, but the
///     modelview matrix will not change!
///  - perform any rendering you want with that render context.
///  - when finished, call Framebuffer::endRendering().  This will clean up
///             everythin and restore the original OpenGL transforms.
///  - the texture now contains whatever was rendered offscreen.
///
/// However, once you create a Framebuffer, it is recommended that you use a
///     FramebufferContext to manage calling setupForRendering() and
///     endRendering() automatically.
class Framebuffer {
public:
        // virtual destructor --------------------------------------------------
        virtual ~Framebuffer(void) throw();

        // glut::Framebuffer class interface methods ---------------------------
        virtual int getWidth(void) const throw() = 0;
        virtual int getHeight(void) const throw() = 0;
        virtual void setupForRendering(IN int textureId,
                                IN const render_context_t& rc) = 0;
        virtual void endRendering(void) throw() = 0;

        // public static methods (factory methods) -----------------------------
        static smart_ptr<Framebuffer> create(IN int width,
                                        IN int height);
};



/// simple helper class--put this on the stack and it will automatically call
///     Framebuffer::setupForRendering() and Framebuffer::endRendering() for
///     you.
class FramebufferContext {
public:
        /// constructor: you must provide the Framebuffer and texture, and the
        ///     render context will be prepared for you.
        FramebufferContext(IN Framebuffer * fbuffer,
                                IN int textureId,
                                IN const render_context_t& rc) {
                        ASSERT(fbuffer, "null");
                        ASSERT(textureId, "null");
                        m_framebuffer = fbuffer;
                        m_framebuffer->setupForRendering(textureId, rc);
                }

        /// destructor: automatically cleans up
        ~FramebufferContext(void) throw() {
                        if (m_framebuffer) {
                                m_framebuffer->endRendering();
                        }
                }

private:
        // private member data -------------------------------------------------
        Framebuffer *           m_framebuffer;  // weak pointer, does not delete
};



};      // glut namespace


#endif  //WAVE_GLUT_EFFECTS_FRAMEBUFFER_H__