245 lines
4.6 KiB
C
245 lines
4.6 KiB
C
/*
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* Copyright 2011-2014 hasufell
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*
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* This file is part of a hasufell project.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation version 2 of the License only.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file vector.c
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* Various operations on the vector struct defined
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* in vector.h, including simple maths.
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* @brief vector operations
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*/
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#include "err.h"
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#include "vector.h"
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#include <errno.h>
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#include <fenv.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdlib.h>
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/**
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* Calculate the vector which lengths is reduced by the
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* factor scal and store it in c.
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* This function is aliasing safe.
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*
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* @param a vector
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* @param scal scalar to multiply the vector with
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* @param c vector [out]
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* @return true/false for success/failure
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*/
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bool vector_len_scal_mul(const vector *a, const float scal, vector *c)
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{
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vector a_tmp;
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float vector_length;
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float factor;
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if (!a || !scal || !c)
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return false;
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copy_vector(a, &a_tmp);
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vector_length = sqrt((a_tmp.x * a_tmp.x) +
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(a_tmp.y * a_tmp.y) + (a_tmp.z * a_tmp.z));
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factor = vector_length * scal;
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c->x = a_tmp.x / vector_length;
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c->y = a_tmp.y / vector_length;
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c->z = a_tmp.z / vector_length;
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c->x = c->x * factor;
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c->y = c->y * factor;
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c->z = c->z * factor;
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return true;
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}
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/**
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* Calculate the vector product of a and b
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* and store it in c. This function is aliasing safe.
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*
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* @param a vector
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* @param b vector
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* @param c vector [out]
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* @return true/false for success/failure
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*/
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bool vector_product(const vector *a, const vector *b, vector *c)
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{
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vector a_tmp,
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b_tmp;
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if (!a || !b || !c)
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return false;
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copy_vector(a, &a_tmp);
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copy_vector(b, &b_tmp);
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c->x = a_tmp.y * b_tmp.z - a_tmp.z * b_tmp.y;
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c->y = a_tmp.z * b_tmp.x - a_tmp.x * b_tmp.z;
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c->z = a_tmp.x * b_tmp.y - a_tmp.y * b_tmp.x;
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return true;
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}
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/**
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* Add vector a to vector b and store the result in c,
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* such as: c = a + b.
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* This function is aliasing safe.
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*
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* @param a vector
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* @param b vector
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* @param c vector [out]
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* @return true/false for success/failure
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*/
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bool add_vectors(const vector *a, const vector *b, vector *c)
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{
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vector a_tmp,
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b_tmp;
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if (!a || !b || !c)
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return false;
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copy_vector(a, &a_tmp);
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copy_vector(b, &b_tmp);
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c->x = a_tmp.x + b_tmp.x;
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c->y = a_tmp.y + b_tmp.y;
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c->z = a_tmp.z + b_tmp.z;
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return true;
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}
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/**
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* Substract vector b from vector a and store the result in c,
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* such as: c = a - b.
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* This function is aliasing safe.
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*
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* @param a vector
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* @param b vector
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* @param c vector [out]
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* @return true/false for success/failure
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*/
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bool sub_vectors(const vector *a, const vector *b, vector *c)
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{
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vector a_tmp,
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b_tmp;
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if (!a || !b || !c)
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return false;
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copy_vector(a, &a_tmp);
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copy_vector(b, &b_tmp);
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c->x = a_tmp.x - b_tmp.x;
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c->y = a_tmp.y - b_tmp.y;
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c->z = a_tmp.z - b_tmp.z;
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return true;
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}
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/**
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* Normalize a vector into a unit vector
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* of length 1. This function is aliasing safe.
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*
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* @param a vector
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* @param b vector [out]
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* @return true/false for success/failure
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*/
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bool normalize_vector(const vector *a, vector *b)
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{
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if (!a || !b)
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return false;
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vector a_tmp;
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float vector_length;
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copy_vector(a, &a_tmp);
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vector_length = sqrt((a_tmp.x * a_tmp.x) +
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(a_tmp.y * a_tmp.y) + (a_tmp.z * a_tmp.z));
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if (errno == EDOM)
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return false;
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b->x = a_tmp.x / vector_length;
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b->y = a_tmp.y / vector_length;
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b->z = a_tmp.z / vector_length;
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return true;
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}
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/**
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* Copy coordinates from vector a to vector b.
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*
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* @param a vector
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* @param b vector [out]
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* @return true/false for success/failure
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*/
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bool copy_vector(const vector *a, vector *b)
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{
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if (!a || !b || (a == b))
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return false;
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b->x = a->x;
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b->y = a->y;
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b->z = a->z;
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return true;
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}
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/**
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* Set the vector to a null vector.
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*
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* @param a vector [out]
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* @return true/false for success/failure
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*/
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bool set_null_vector(vector *a)
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{
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if (!a)
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return false;
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a->x = 0;
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a->y = 0;
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a->z = 0;
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return true;
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}
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/**
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* Check if vector a is a null vector,
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* so all coordinates are 0.
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*
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* @param a vector
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* @return true if vector is a null vector, false
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* otherwise, -1 on failure
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*/
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int is_null_vector(const vector *a)
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{
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if (!a)
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return -1;
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if (a->x == 0 &&
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a->y == 0 &&
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a->z == 0)
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return true;
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else
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return false;
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}
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