From 7b09710392d35fb55b52031d447a542d99fc6b4b Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Tue, 19 Aug 2014 17:10:03 -0400 Subject: Modularize the libdimension codebase. --- libdimension/dimension/math/vector.h | 183 +++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 libdimension/dimension/math/vector.h (limited to 'libdimension/dimension/math/vector.h') diff --git a/libdimension/dimension/math/vector.h b/libdimension/dimension/math/vector.h new file mode 100644 index 0000000..8eacee9 --- /dev/null +++ b/libdimension/dimension/math/vector.h @@ -0,0 +1,183 @@ +/************************************************************************* + * Copyright (C) 2009-2014 Tavian Barnes * + * * + * This file is part of The Dimension Library. * + * * + * The Dimension Library 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. * + * * + * The Dimension 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 * + * 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 * + * . * + *************************************************************************/ + +/** + * @file + * Vectors in 3-D space. + */ + +#ifndef DMNSN_MATH_H +#error "Please include instead of this header directly." +#endif + +#include +#include + +/** A vector in 3 dimensions. */ +typedef struct dmnsn_vector { + double x; /**< The x component. */ + double y; /**< The y component. */ + double z; /**< The z component. */ +} dmnsn_vector; + +/** A standard format string for vectors. */ +#define DMNSN_VECTOR_FORMAT "<%g, %g, %g>" +/** The appropriate arguements to printf() a vector. */ +#define DMNSN_VECTOR_PRINTF(v) (v).x, (v).y, (v).z + +/* Constants */ + +/** The zero vector. */ +static const dmnsn_vector dmnsn_zero = { 0.0, 0.0, 0.0 }; +/** The x vector. */ +static const dmnsn_vector dmnsn_x = { 1.0, 0.0, 0.0 }; +/** The y vector. */ +static const dmnsn_vector dmnsn_y = { 0.0, 1.0, 0.0 }; +/** The z vector. */ +static const dmnsn_vector dmnsn_z = { 0.0, 0.0, 1.0 }; + +/* Shorthand for vector construction */ + +/** Construct a new vector. */ +DMNSN_INLINE dmnsn_vector +dmnsn_new_vector(double x, double y, double z) +{ + dmnsn_vector v = { x, y, z }; + return v; +} + +/* Vector arithmetic */ + +/** Negate a vector. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_negate(dmnsn_vector rhs) +{ + /* 3 negations */ + dmnsn_vector v = { -rhs.x, -rhs.y, -rhs.z }; + return v; +} + +/** Add two vectors. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs) +{ + /* 3 additions */ + dmnsn_vector v = { lhs.x + rhs.x, lhs.y + rhs.y, lhs.z + rhs.z }; + return v; +} + +/** Subtract two vectors. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_sub(dmnsn_vector lhs, dmnsn_vector rhs) +{ + /* 3 additions */ + dmnsn_vector v = { lhs.x - rhs.x, lhs.y - rhs.y, lhs.z - rhs.z }; + return v; +} + +/** Multiply a vector by a scalar. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_mul(double lhs, dmnsn_vector rhs) +{ + /* 3 multiplications */ + dmnsn_vector v = { lhs*rhs.x, lhs*rhs.y, lhs*rhs.z }; + return v; +} + +/** Divide a vector by a scalar. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_div(dmnsn_vector lhs, double rhs) +{ + /* 3 divisions */ + dmnsn_vector v = { lhs.x/rhs, lhs.y/rhs, lhs.z/rhs }; + return v; +} + +/** Return the dot product of two vectors. */ +DMNSN_INLINE double +dmnsn_vector_dot(dmnsn_vector lhs, dmnsn_vector rhs) +{ + /* 3 multiplications, 2 additions */ + return lhs.x*rhs.x + lhs.y*rhs.y + lhs.z*rhs.z; +} + +/** Return the cross product of two vectors. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_cross(dmnsn_vector lhs, dmnsn_vector rhs) +{ + /* 6 multiplications, 3 additions */ + dmnsn_vector v = { lhs.y*rhs.z - lhs.z*rhs.y, + lhs.z*rhs.x - lhs.x*rhs.z, + lhs.x*rhs.y - lhs.y*rhs.x }; + return v; +} + +/** Return the projection of \p u onto \p d. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_proj(dmnsn_vector u, dmnsn_vector d) +{ + /* 1 division, 9 multiplications, 4 additions */ + return dmnsn_vector_mul(dmnsn_vector_dot(u, d)/dmnsn_vector_dot(d, d), d); +} + +/** Return the magnitude of a vector. */ +DMNSN_INLINE double +dmnsn_vector_norm(dmnsn_vector n) +{ + /* 1 sqrt, 3 multiplications, 2 additions */ + return sqrt(dmnsn_vector_dot(n, n)); +} + +/** Return the direction of a vector. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_normalized(dmnsn_vector n) +{ + /* 1 sqrt, 3 divisions, 3 multiplications, 2 additions */ + return dmnsn_vector_div(n, dmnsn_vector_norm(n)); +} + +/** Return the component-wise minimum of two vectors. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_min(dmnsn_vector a, dmnsn_vector b) +{ + return dmnsn_new_vector( + dmnsn_min(a.x, b.x), + dmnsn_min(a.y, b.y), + dmnsn_min(a.z, b.z) + ); +} + +/** Return the component-wise maximum of two vectors. */ +DMNSN_INLINE dmnsn_vector +dmnsn_vector_max(dmnsn_vector a, dmnsn_vector b) +{ + return dmnsn_new_vector( + dmnsn_max(a.x, b.x), + dmnsn_max(a.y, b.y), + dmnsn_max(a.z, b.z) + ); +} + +/** Return whether a vector contains any NaN components. */ +DMNSN_INLINE bool +dmnsn_vector_isnan(dmnsn_vector v) +{ + return dmnsn_isnan(v.x) || dmnsn_isnan(v.y) || dmnsn_isnan(v.z); +} -- cgit v1.2.3