//

// Author:    Philip Rideout

// Copyright: 2002-2006  3Dlabs Inc. Ltd.  All rights reserved.

// License:   see 3Dlabs-license.txt

//

#include "os.h"

#include <cmath>

#include "Vector.h"

// Basic vector math.  This is by no means complete; add to this file as necessary.

float vec3::magnitude() const

{

    return sqrtf(mag2());

}

float vec3::mag2() const

{

    return x*x + y*y + z*z;

}

void vec3::unitize()

{

    float m = magnitude();

    x /= m;

    y /= m;

    z /= m;

}

float dot(const vec3& a, const vec3& b)

{

    return a.x*b.x + a.y*b.y + a.z*b.z;

}

vec3 cross(const vec3& u, const vec3& v)

{

    return vec3(u.y*v.z-u.z*v.y, u.z*v.x-u.x*v.z, u.x*v.y-u.y*v.x);

}

mat4 operator*(const mat4& a, const mat4& b)

{

    mat4 retval;

    glPushMatrix();

    glLoadMatrixf(a.data);

    glMultMatrixf(b.data);

    glGetFloatv(GL_MODELVIEW_MATRIX, retval.data);

    glPopMatrix();

    return retval;

}

vec2 operator*(const vec2& v, const mat4& m)

{

    float x = m.data[0] * v.x + m.data[4] * v.y + m.data[12];

    float y = m.data[1] * v.x + m.data[5] * v.y + m.data[13];

    return vec2(x, y);

}

vec3 blend(const vec3& v, const mat4& m0, const mat4& m1, float w0, float w1)

{

    return v * m0 * w0 + v * m1 * w1;

}

vec3 operator*(const vec3& v, const mat4& m)

{

    float x = m.data[0] * v.x + m.data[4] * v.y + m.data[8] * v.z  + m.data[12];

    float y = m.data[1] * v.x + m.data[5] * v.y + m.data[9] * v.z  + m.data[13];

    float z = m.data[2] * v.x + m.data[6] * v.y + m.data[10] * v.z + m.data[14];

    return vec3(x, y, z);

}

void mat4::identity()

{

    for (int i = 0; i < 4; ++i)

        for (int j = 0; j < 4; ++j)

            data[i*4 + j] = (i == j) ? 1.0f : 0.0f;

}

void glVertex(const vec3& v)

{

    glVertex3fv((float*) &v);

}

void glVertex(const vec2& v)

{

    glVertex2fv((float*) &v);

}

void glNormal(const vec3& v)

{

    glNormal3fv((float*) &v);

}

void glColor(const vec3& v)

{

    glColor4f(v.x, v.y, v.z, 1);

}

void glTexCoord(const vec2& v)

{

    glTexCoord2f(v.x, v.y);

}

void glTranslate(const vec3& v)

{

    glTranslatef(v.x, v.y, v.z);

}

void glVertexAttrib(unsigned int loc, const vec3& v)

{

    glVertexAttrib3fv(loc, &v.x);

}

bool vec3::operator<(const vec3& v) const

{

    if (x != v.x)

        return x < v.x;

    if (y != v.y)

        return y < v.y;

    return z < v.z;

}