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82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
// This code is in the public domain -- castanyo@yahoo.es
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#ifndef NV_MATH_BASIS_H
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#define NV_MATH_BASIS_H
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#include <nvmath/nvmath.h>
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#include <nvmath/Vector.h>
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#include <nvmath/Matrix.h>
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namespace nv
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{
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/// Basis class to compute tangent space basis, ortogonalizations and to
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/// transform vectors from one space to another.
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class Basis
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{
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public:
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/// Create a null basis.
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Basis() : tangent(0, 0, 0), bitangent(0, 0, 0), normal(0, 0, 0) {}
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/// Create a basis given three vectors.
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Basis(Vector3::Arg n, Vector3::Arg t, Vector3::Arg b) : tangent(t), bitangent(b), normal(n) {}
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/// Create a basis with the given tangent vectors and the handness.
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Basis(Vector3::Arg n, Vector3::Arg t, float sign)
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{
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build(n, t, sign);
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}
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NVMATH_API void normalize(float epsilon = NV_EPSILON);
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NVMATH_API void orthonormalize(float epsilon = NV_EPSILON);
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NVMATH_API void robustOrthonormalize(float epsilon = NV_EPSILON);
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NVMATH_API void buildFrameForDirection(Vector3::Arg d);
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/// Calculate the determinant [ F G N ] to obtain the handness of the basis.
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float handness() const
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{
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return determinant() > 0.0f ? 1.0f : -1.0f;
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}
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/// Build a basis from 2 vectors and a handness flag.
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void build(Vector3::Arg n, Vector3::Arg t, float sign)
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{
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normal = n;
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tangent = t;
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bitangent = sign * cross(t, n);
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}
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/// Compute the determinant of this basis.
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float determinant() const
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{
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return
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tangent.x() * bitangent.y() * normal.z() - tangent.z() * bitangent.y() * normal.x() +
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tangent.y() * bitangent.z() * normal.x() - tangent.y() * bitangent.x() * normal.z() +
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tangent.z() * bitangent.x() * normal.y() - tangent.x() * bitangent.z() * normal.y();
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}
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bool isValid() const;
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// Get transform matrix for this basis.
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NVMATH_API Matrix matrix() const;
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// Transform by this basis. (From this basis to object space).
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NVMATH_API Vector3 transform(Vector3::Arg v) const;
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// Transform by the transpose. (From object space to this basis).
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NVMATH_API Vector3 transformT(Vector3::Arg v);
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// Transform by the inverse. (From object space to this basis).
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NVMATH_API Vector3 transformI(Vector3::Arg v) const;
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Vector3 tangent;
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Vector3 bitangent;
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Vector3 normal;
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};
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} // nv namespace
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#endif // NV_MATH_BASIS_H
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