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simgear/simgear/math/project.cxx
T

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C++

// Copyright (C) 2010 Tim Moore moore@bricoworks.com
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
#include "project.hxx"
#include <osg/Math>
#include <osg/Matrixd>
namespace simgear
{
GLint project(GLdouble objX, GLdouble objY, GLdouble objZ,
const GLdouble *model, const GLdouble *proj, const GLint *view,
GLdouble* winX, GLdouble* winY, GLdouble* winZ)
{
using namespace osg;
Vec4d obj(objX, objY, objZ, 1.0);
Matrixd Mmodel(model), Mproj(proj);
Matrixd Mwin = (Matrixd::translate(1.0, 1.0, 1.0)
* Matrixd::scale(0.5 * view[2], 0.5 * view[3], 0.5)
* Matrixd::translate(view[0], view[1], 0.0));
Vec4d result = obj * Mmodel * Mproj * Mwin;
if (equivalent(result.w(), 0.0))
return GL_FALSE;
result = result / result.w();
*winX = result.x(); *winY = result.y(); *winZ = result.z();
return GL_TRUE;
}
}