QVector.c

Go to the documentation of this file.

#include "Internal.h"

#include <string.h>
#include "math.h"
#include "QVector.h"

double* vec_mul(double vec[3], double k)
{
    int i;
    for (i = 0; i < 3; i++)
        vec[i] *=k;

    return vec;
}

double vec_magnitude(double vec[3])
{
    double magnitude = 0;
    int i;
    for (i = 0; i < 3; i++)
        magnitude += vec[i] * vec[i];

    return pow(magnitude, 0.5);
}

double* vec_once(double vec[3])
{
    int i;
    double magnitude = vec_magnitude(vec);

    for (i = 0; i != 3; i++)
        vec[i] /= magnitude;

    return vec;
}

double* vec_ofpow(double vec[3], double power)
{
    int i;
    double magnitude = power/vec_magnitude(vec);

    for (i = 0; i < 3; i++)
        vec[i] *= magnitude;

    return vec;
}


double* vec_rotateY(double vec[3], double angle)
{
    double 
        a = cos(angle),
        b = sin(angle),
        tx = vec[0] * a  + vec[2] * b,
        ty = -vec[0] * b + vec[2] * a;

    vec[0] = tx;
    vec[2] = ty;

    return  vec;
}
double* vec_add(double vec1[3], const double vec2[3])
{
    int i;
    for (i=0; i<3; i++)
        vec1[i] += vec2[i];

    return vec1;
}
double* vec_adddiff(double vec1[3], const double vec2[3], const double vec3[3])
{
    int i;
    for (i=0; i<3; i++)
        vec1[i] += vec3[i] - vec2[i];

    return vec1;
}

int vec_eq(const double vec1[3], const double vec2[3])
{
    int i;
    for (i = 0; i < 3; i++)
    {
        if (vec1[i] != vec2[i])
            return 0;
    }
    return 1;
}

void draw_circle(double rad, int severity)
{
    int i;
    double vec[] = { rad, 0.0, 0.0 };
    double pove[3];
    GLfloat normal[] = { 0.0, -1.0, 0.0 }; 
  

    glBegin(GL_POLYGON);
    
    glNormal3fv(normal);   
    glVertex3f(vec[0], vec[1], vec[2]);
    for (i = 1; i < severity; i++)
    {
        memcpy(pove, vec, sizeof(vec) );
        vec_rotateY(pove, -2 * i * M_PI / severity);
        glNormal3fv(normal);
        glVertex3f(pove[0], pove[1], pove[2]);
    }
    glEnd();
}

const double VZERO[3] = { 0.0, 0.0, 0.0 };