frustum.h

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/*
 * frustum.h
 *
 * Copyright (C) 2009  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.
 *
 *
 * View frustum routines.  Mosly used for culling.
 */

#ifndef WAVE_GLUT_GLUT_FRUSTUM_H__
#define WAVE_GLUT_GLUT_FRUSTUM_H__

// includes --------------------------------------------------------------------
#include "camera.h"
#include "color/color.h"

#include "geometry/frustum.h"


namespace glut {

/// \ingroup glut
/*@{*/

/// This is a method to determine the view frustum given the current
///   camera settings and viewer orientation.
/// What is a frustum?  It is a basic 3D solid.  See
///   http://en.wikipedia.org/wiki/Frustum
/// In particular, this is a clipped 4-sided pyramid, also called a
///   right square frustum.
/// In 3D rendering, a frustum defines the area of space that can be seen from
///   the current camera, given its position and orientation.  This is called
///   the view frustrum.
/// Given other objects, we can quickly test if they are inside the view
///   frustrum or not.  If not, we can avoid rendering them altogether.  This
///   is called culling.  If you have partitioned your object space (always a
///   good idea), you can cull dozens or hundreds of objects with a single
///   frustum/rectangle test.
///
/// For more links on view frustrum culling try:
///  - http://www.lighthouse3d.com/opengl/viewfrustum/index.php?intro
///  - http://www.racer.nl/reference/vfc.htm
///
/// Or for an up-to-date search:
///   http://www.google.com/search?q=opengl+view+frustum+culling
void getViewFrustum(IN const camera_t& camera,
                        IN const Viewer& viewer,
                        OUT frustum_t& viewFrustum) throw();


/// helper method to draw the edges of a frustum
void drawFrustumEdges(IN const frustum_t& f,
                        IN const glut_color_t& color) throw();


};      // glut namespace

#endif  // WAVE_GLUT_GLUT_FRUSTUM_H__