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#ifndef Magnum_DebugTools_Implementation_ForceRendererTransformation_h
#define Magnum_DebugTools_Implementation_ForceRendererTransformation_h
/*
Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
This file is part of Magnum.
Magnum is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 3
only, as published by the Free Software Foundation.
Magnum 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 Lesser General Public License version 3 for more details.
*/
#include "Math/Matrix3.h"
#include "Math/Matrix4.h"
#include "Magnum.h"
#include "DimensionTraits.h"
namespace Magnum { namespace DebugTools { namespace Implementation {
template<UnsignedInt dimensions> typename DimensionTraits<dimensions>::MatrixType forceRendererTransformation(const typename DimensionTraits<dimensions>::VectorType& forcePosition, const typename DimensionTraits<dimensions>::VectorType& force);
template<> inline Matrix3 forceRendererTransformation<2>(const Vector2& forcePosition, const Vector2& force) {
return Matrix3::from({force, Vector2(-force.y(), force.x())}, forcePosition);
}
template<> inline Matrix4 forceRendererTransformation<3>(const Vector3& forcePosition, const Vector3& force) {
const Matrix4 translation = Matrix4::translation(forcePosition);
const Float forceLength = force.length();
/* Zero length, zero scaling */
if(forceLength < Math::MathTypeTraits<Float>::epsilon())
return translation*Matrix4::scaling(Vector3(0.0f));
const Float dot = Vector3::dot(force/forceLength, Vector3::xAxis());
/* Force is parallel to X axis, just scaling */
if(dot > 1.0f - Math::MathTypeTraits<Float>::epsilon())
return translation*Matrix4::scaling(Vector3(forceLength));
/* Force is antiparallel to X axis, scaling inverted on X */
if(-dot > 1.0f - Math::MathTypeTraits<Float>::epsilon())
return translation*Matrix4::scaling({-forceLength, forceLength, forceLength});
/* Normal of plane going through force vector and X axis vector */
const Vector3 normal = Vector3::cross(Vector3::xAxis(), force).normalized();
/* Third base vector, orthogonal to force and normal */
const Vector3 binormal = Vector3::cross(normal, force).normalized();
/* Transformation matrix from scaled base vectors and translation vector */
return Matrix4::from({force, normal*forceLength, binormal*forceLength}, forcePosition);
}
}}}
#endif