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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of Dimension. *
* *
* Dimension is free software; you can redistribute it and/or modify it *
* under the terms of the GNU Lesser General Public License as published *
* by the Free Software Foundation; either version 3 of the License, or *
* (at your option) any later version. *
* *
* Dimension 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 for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
/*
* Core geometric types like scalars, vectors, and rays.
*/
#ifndef DIMENSION_GEOMETRY_H
#define DIMENSION_GEOMETRY_H
/* Scalar and vector types. */
typedef double dmnsn_scalar;
typedef struct { dmnsn_scalar x, y, z; } dmnsn_vector;
/* Vector arithmetic */
inline dmnsn_vector
dmnsn_vector_construct(dmnsn_scalar x, dmnsn_scalar y, dmnsn_scalar z)
{
dmnsn_vector v = { .x = x, .y = y, .z = z };
return v;
}
inline dmnsn_vector
dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs)
{
return dmnsn_vector_construct(lhs.x + rhs.x, lhs.y + rhs.y, lhs.z + rhs.z);
}
inline dmnsn_vector
dmnsn_vector_sub(dmnsn_vector lhs, dmnsn_vector rhs)
{
return dmnsn_vector_construct(lhs.x - rhs.x, lhs.y - rhs.y, lhs.z - rhs.z);
}
inline dmnsn_vector
dmnsn_vector_mul(dmnsn_scalar lhs, dmnsn_vector rhs)
{
return dmnsn_vector_construct(lhs*rhs.x, lhs*rhs.y, lhs*rhs.z);
}
inline dmnsn_vector
dmnsn_vector_div(dmnsn_vector lhs, dmnsn_scalar rhs)
{
return dmnsn_vector_construct(lhs.x/rhs, lhs.y/rhs, lhs.z/rhs);
}
inline dmnsn_scalar
dmnsn_vector_dot(dmnsn_vector lhs, dmnsn_vector rhs)
{
return lhs.x*rhs.x + lhs.y*rhs.y + lhs.z*rhs.z;
}
inline dmnsn_vector
dmnsn_vector_cross(dmnsn_vector lhs, dmnsn_vector rhs)
{
return dmnsn_vector_construct(lhs.y*rhs.z - lhs.z*rhs.y,
lhs.z*rhs.x - lhs.x*rhs.z,
lhs.x*rhs.y - lhs.y*rhs.x);
}
/* A line, or ray. */
typedef struct {
dmnsn_vector x0; /* A point on the line */
dmnsn_vector n; /* A normal vector; the direction of the line */
} dmnsn_line;
/* A point on a line, defined by x0 + t*n */
inline dmnsn_vector
dmnsn_line_point(dmnsn_line l, dmnsn_scalar t)
{
return dmnsn_vector_add(l.x0, dmnsn_vector_mul(t, l.n));
}
#endif /* DIMENSION_GEOMETRY_H */
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