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00001 
+00007 /* Copyright, 2000, 2001 Nevrax Ltd.
+00008  *
+00009  * This file is part of NEVRAX NEL.
+00010  * NEVRAX NEL is free software; you can redistribute it and/or modify
+00011  * it under the terms of the GNU General Public License as published by
+00012  * the Free Software Foundation; either version 2, or (at your option)
+00013  * any later version.
+00014 
+00015  * NEVRAX NEL is distributed in the hope that it will be useful, but
+00016  * WITHOUT ANY WARRANTY; without even the implied warranty of
+00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+00018  * General Public License for more details.
+00019 
+00020  * You should have received a copy of the GNU General Public License
+00021  * along with NEVRAX NEL; see the file COPYING. If not, write to the
+00022  * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+00023  * MA 02111-1307, USA.
+00024  */
+00025 
+00026 #include "std3d.h"
+00027 
+00028 
+00029 #include "3d/heat_haze.h"
+00030 #include "3d/scene.h"
+00031 #include "3d/deform_2d.h"
+00032 #include "nel/misc/vector_2f.h"
+00033 
+00034 namespace NL3D
+00035 {
+00036         
+00037 
+00038         struct CSinWave : public CDeform2d::IPerturbUV
+00039         {
+00040                 float Phase;
+00041                 virtual void perturbUV(float x, float y, float &du, float &dv) const
+00042                 {
+00043                         du = 0.01f * sinf(25.f * y + Phase);
+00044                         dv = 0.05f * cosf(19.3f * x + Phase);
+00045                 }
+00046         } _SinWave;
+00047 
+00048         
+00049 
+00050 
+00051         void CHeatHaze::performHeatHaze(uint width, uint height, CScene &s, IDriver *drv)       
+00052         {
+00053                 NLMISC::CMatrix m  = s.getCam()->getMatrix();
+00054                 NLMISC::CMatrix im = m.inverted();
+00055 
+00056                 // compute the shape of the horizon
+00057 
+00058                 // first we compute the direction of the world up vector in the viewer basis.   
+00059                 NLMISC::CVector up = im * NLMISC::CVector::K;
+00060                 // project onto the I and K vectors
+00061                 float upNorm = (up.x * up.x + up.z * up.z);
+00062 
+00063                 const float threshold = 10E-4f;
+00064 
+00065                 if (upNorm < threshold) return; // the viewer is looking above or below  himlself
+00066 
+00067                 // Compute the right vector. This is done by intersecting the horizon plane with a near plane. 
+00068                 // to do this, we transform the horizon plane into the view basis.This may be optimized, but is not critical.
+00069                 //
+00070                 NLMISC::CPlane h;
+00071                 h.make(NLMISC::CVector::K, NLMISC::CVector::Null);
+00072 
+00073                 h = h * m; // note : this multiply by the transposition of m
+00074 
+00075                 // intersect with near plane : we got y = 0, which gives us, as a right vector :
+00076                 // if c is not 0, we got : x = 1 and z = (-a - d) / c as a working solution.
+00077                 // Else we got x = (- d - c )/ a and z = 1
+00078 
+00079 
+00080                 NLMISC::CVector right;
+00081 
+00082                 if (fabsf(h.c) > threshold)
+00083                 {
+00084                         right.set(1, 0, (h.a + h.d) / - h.c );
+00085                 }
+00086                 else
+00087                 {
+00088                         right.set( (h.d + h.c) / h.a, 0,  1);
+00089                 }
+00090 
+00091                 right.normalize();
+00092 
+00093                 // now, find a point on screen that lay on the horizon line
+00094                 static std::vector<NLMISC::CVector2f> poly(4);          
+00095 
+00096                 
+00097 
+00098                 const sint xCenter = width >> 1;
+00099                 const sint yCenter = height >> 1;
+00100 
+00101                 const float horizonHeight = (float) (height >> 2);
+00102                 const float horizonWidth  = (float) (width  >> 2);
+00103 
+00104                 NLMISC::CVector tmp ;
+00105 
+00106                 tmp = horizonWidth * right + horizonHeight * up;
+00107                 poly[0] = NLMISC::CVector2f(xCenter + tmp.x, yCenter + tmp.z) ;
+00108                 tmp = horizonWidth   * right - horizonHeight  * up;
+00109                 poly[1] = NLMISC::CVector2f(xCenter + tmp.x, yCenter + tmp.z) ;
+00110                 tmp = - horizonWidth   * right - horizonHeight  * up;
+00111                 poly[2] = NLMISC::CVector2f(xCenter + tmp.x, yCenter + tmp.z);
+00112                 tmp = - horizonWidth   * right + horizonHeight  * up;
+00113                 poly[3] = NLMISC::CVector2f(xCenter + tmp.x, yCenter + tmp.z);
+00114 
+00115 
+00116                 CDeform2d::doDeform(poly, drv, &_SinWave);
+00117 
+00118 
+00119 
+00120 
+00121         }
+00122 
+00123 } // NL3D
+
heat_haze.cpp
