# Visualization Library

A lightweight C++ OpenGL middleware for 2D/3D graphics

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# D:/VL/BuildSystem/VL_DISTRO/Visualization_Library_SDK/src/vlCore/math_utils.cpp

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    00001 /**************************************************************************************/
    00002 /*                                                                                    */
    00003 /*  Visualization Library                                                             */
    00004 /*  http://www.visualizationlibrary.org                                               */
    00005 /*                                                                                    */
    00006 /*  Copyright (c) 2005-2010, Michele Bosi                                             */
    00007 /*  All rights reserved.                                                              */
    00008 /*                                                                                    */
    00009 /*  Redistribution and use in source and binary forms, with or without modification,  */
    00010 /*  are permitted provided that the following conditions are met:                     */
    00011 /*                                                                                    */
    00012 /*  - Redistributions of source code must retain the above copyright notice, this     */
    00013 /*  list of conditions and the following disclaimer.                                  */
    00014 /*                                                                                    */
    00015 /*  - Redistributions in binary form must reproduce the above copyright notice, this  */
    00016 /*  list of conditions and the following disclaimer in the documentation and/or       */
    00017 /*  other materials provided with the distribution.                                   */
    00018 /*                                                                                    */
    00019 /*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND   */
    00020 /*  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED     */
    00021 /*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE            */
    00022 /*  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR  */
    00023 /*  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    */
    00024 /*  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;      */
    00025 /*  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON    */
    00026 /*  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT           */
    00027 /*  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS     */
    00028 /*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.                      */
    00029 /*                                                                                    */
    00030 /**************************************************************************************/
    00031
    00032 #include <vlCore/math_utils.hpp>
    00033 #include <vlCore/AABB.hpp>
    00034 #include <vlCore/Vector2.hpp>
    00035 #include <vlCore/Vector4.hpp>
    00036 #include <vlCore/Plane.hpp>
    00037 #include <vlCore/checks.hpp>
    00038 #include <vlCore/MersenneTwister.hpp>
    00039 #include <cstdlib>
    00040
    00041 using namespace vl;
    00042
    00043 //-----------------------------------------------------------------------------
    00044 real vl::random(real min, real max)
    00045 {
    00046   real t = (real)defMersenneTwister()->rand53();
    00047   return min + (max-min)*t;
    00048 }
    00049 //-----------------------------------------------------------------------------
    00050 u32 vl::randomU32(u32 min, u32 max)
    00051 {
    00052   return defMersenneTwister()->randInt(max-min) + min;
    00053 }
    00054 //-----------------------------------------------------------------------------
    00055 i32 vl::randomI32(i32 min, i32 max)
    00056 {
    00057   return defMersenneTwister()->randInt(max-min) + min;
    00058 }
    00059 //-----------------------------------------------------------------------------
    00060 int vl::greaterEqualPow2(int n)
    00061 {
    00062   int pow2=2;
    00063   for(int i=0; i<20; ++i) {
    00064     if (pow2 >= n)
    00065       return pow2;
    00066     pow2 = pow2 * 2;
    00067   }
    00068   return pow2;
    00069 }
    00070 //-----------------------------------------------------------------------------
    00071 int vl::smallerEqualPow2(int n)
    00072 {
    00073   int pow2=2;
    00074   for(int i=0; i<20; ++i) {
    00075     if (pow2 > n)
    00076       return pow2/2;
    00077     pow2 = pow2 * 2;
    00078   }
    00079   return pow2;
    00080 }
    00081 //-----------------------------------------------------------------------------
    00082 void vl::extractPlanes( Plane* planes, const mat4& modelviewproj )
    00083 {
    00084   // see also http://www2.ravensoft.com/users/ggribb/plane%20extraction.pdf
    00085   // see also http://zach.in.tu-clausthal.de/teaching/cg_literatur/lighthouse3d_view_frustum_culling/index.html
    00086   // the equation is a*x+b*y+x*z+d = 0
    00087   // where <a b c> is the normal of the plane
    00088   // the normals are pointing inside the viewfrustum
    00089
    00090   // 1) we want the planes to point outward so we reverse them
    00091   // 2) because of 1) "d" becomes the distance of the plane from the origin
    00092
    00093   vec3 n;
    00094   real d;
    00095
    00096   // left clipping plane
    00097   n.x() = modelviewproj.e(3,0) + modelviewproj.e(0,0);
    00098   n.y() = modelviewproj.e(3,1) + modelviewproj.e(0,1);
    00099   n.z() = modelviewproj.e(3,2) + modelviewproj.e(0,2);
    00100   d = modelviewproj.e(3,3) + modelviewproj.e(0,3);
    00101   d /= n.length();
    00102   n.normalize();
    00103   planes[0] = Plane(d,-n);
    00104
    00105   // right clipping plane
    00106   n.x() = modelviewproj.e(3,0) - modelviewproj.e(0,0);
    00107   n.y() = modelviewproj.e(3,1) - modelviewproj.e(0,1);
    00108   n.z() = modelviewproj.e(3,2) - modelviewproj.e(0,2);
    00109   d = modelviewproj.e(3,3) - modelviewproj.e(0,3);
    00110   d /= n.length();
    00111   n.normalize();
    00112   planes[1] = Plane(d,-n);
    00113
    00114   // top clipping plane
    00115   n.x() = modelviewproj.e(3,0) - modelviewproj.e(1,0);
    00116   n.y() = modelviewproj.e(3,1) - modelviewproj.e(1,1);
    00117   n.z() = modelviewproj.e(3,2) - modelviewproj.e(1,2);
    00118   d = modelviewproj.e(3,3) - modelviewproj.e(1,3);
    00119   d /= n.length();
    00120   n.normalize();
    00121   planes[2] = Plane(d,-n);
    00122
    00123   // bottom clipping plane
    00124   n.x() = modelviewproj.e(3,0) + modelviewproj.e(1,0);
    00125   n.y() = modelviewproj.e(3,1) + modelviewproj.e(1,1);
    00126   n.z() = modelviewproj.e(3,2) + modelviewproj.e(1,2);
    00127   d = modelviewproj.e(3,3) + modelviewproj.e(1,3);
    00128   d /= n.length();
    00129   n.normalize();
    00130   planes[3] = Plane(d,-n);
    00131
    00132   // near clipping plane
    00133   n.x() = modelviewproj.e(3,0) + modelviewproj.e(2,0);
    00134   n.y() = modelviewproj.e(3,1) + modelviewproj.e(2,1);
    00135   n.z() = modelviewproj.e(3,2) + modelviewproj.e(2,2);
    00136   d = modelviewproj.e(3,3) + modelviewproj.e(2,3);
    00137   d /= n.length();
    00138   n.normalize();
    00139   planes[4] = Plane(d,-n);
    00140
    00141   // far clipping plane
    00142   n.x() = modelviewproj.e(3,0) - modelviewproj.e(2,0);
    00143   n.y() = modelviewproj.e(3,1) - modelviewproj.e(2,1);
    00144   n.z() = modelviewproj.e(3,2) - modelviewproj.e(2,2);
    00145   d = modelviewproj.e(3,3) - modelviewproj.e(2,3);
    00146   d /= n.length();
    00147   n.normalize();
    00148   planes[5] = Plane(d,-n);
    00149 }

Visualization Library v2011.09.1162 Reference Documentation
Copyright 2005-2011 Michele Bosi. All rights reserved.
Updated on Thu Jan 26 2012 00:43:28.
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