lib3ds_vector.c

/*
    Copyright (C) 1996-2008 by Jan Eric Kyprianidis <www.kyprianidis.com>
    All rights reserved.
    
    This program 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 2.1 of the License, or 
    (at your option) any later version.

    Thisprogram  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/>. 
*/

#include "lib3ds_impl.h"


void 
lib3ds_vector_make(float c[3], float x, float y, float z) {
    c[0] = x;
    c[1] = y;
    c[2] = z;
}


void
lib3ds_vector_zero(float c[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        c[i] = 0.0f;
    }
}


void
lib3ds_vector_copy(float dst[3], float src[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        dst[i] = src[i];
    }
}


void
lib3ds_vector_add(float c[3], float a[3], float b[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        c[i] = a[i] + b[i];
    }
}


void
lib3ds_vector_sub(float c[3], float a[3], float b[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        c[i] = a[i] - b[i];
    }
}


void
lib3ds_vector_scalar_mul(float c[3], float a[3], float k) {
    int i;
    for (i = 0; i < 3; ++i) {
        c[i] = a[i] * k;
    }
}


void
lib3ds_vector_cross(float c[3], float a[3], float b[3]) {
    c[0] = a[1] * b[2] - a[2] * b[1];
    c[1] = a[2] * b[0] - a[0] * b[2];
    c[2] = a[0] * b[1] - a[1] * b[0];
}


float
lib3ds_vector_dot(float a[3], float b[3]) {
    return(a[0]*b[0] + a[1]*b[1] + a[2]*b[2]);
}


float
lib3ds_vector_length(float c[3]) {
    return((float)sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]));
}


void
lib3ds_vector_normalize(float c[3]) {
    float l, m;

    l = (float)sqrt(c[0] * c[0] + c[1] * c[1] + c[2] * c[2]);
    if (fabs(l) < LIB3DS_EPSILON) {
        if ((c[0] >= c[1]) && (c[0] >= c[2])) {
            c[0] = 1.0f;
            c[1] = c[2] = 0.0f;
        } else
            if (c[1] >= c[2]) {
                c[1] = 1.0f;
                c[0] = c[2] = 0.0f;
            } else {
                c[2] = 1.0f;
                c[0] = c[1] = 0.0f;
            }
    } else {
        m = 1.0f / l;
        c[0] *= m;
        c[1] *= m;
        c[2] *= m;
    }
}


void
lib3ds_vector_normal(float n[3], float a[3], float b[3], float c[3]) {
    float p[3], q[3];

    lib3ds_vector_sub(p, c, b);
    lib3ds_vector_sub(q, a, b);
    lib3ds_vector_cross(n, p, q);
    lib3ds_vector_normalize(n);
}


void
lib3ds_vector_transform(float c[3], float m[4][4], float a[3]) {
    c[0] = m[0][0] * a[0] + m[1][0] * a[1] + m[2][0] * a[2] + m[3][0];
    c[1] = m[0][1] * a[0] + m[1][1] * a[1] + m[2][1] * a[2] + m[3][1];
    c[2] = m[0][2] * a[0] + m[1][2] * a[1] + m[2][2] * a[2] + m[3][2];
}


void
lib3ds_vector_min(float c[3], float a[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        if (a[i] < c[i]) {
            c[i] = a[i];
        }
    }
}


void
lib3ds_vector_max(float c[3], float a[3]) {
    int i;
    for (i = 0; i < 3; ++i) {
        if (a[i] > c[i]) {
            c[i] = a[i];
        }
    }
}


void
lib3ds_vector_dump(float c[3]) {
    fprintf(stderr, "%f %f %f\n", c[0], c[1], c[2]);
}

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