glvector.cpp

实战粒子系统例程

/*
	glvector.cpp - Vector class
	Copyright (c) HalfLucifer, 2001.6.12
*/
#include "glvector.h"

float GLvector::Length() 
{
	double length = (v[0] * v[0]) + (v[1] * v[1]) + (v[2] * v[2]);	
	return (float) sqrt(length);
}

void GLvector::Normalize() 
{
	float length, len = 0;

	length = Length();
	if (length == 0)
		return;

	len = 1.0f / length;
	v[0] *= len;
	v[1] *= len;
	v[2] *= len;
}

void GLvector::CrossProduct(const GLvector &p, const GLvector &q)
{
	v[0] = (p.v[1] * q.v[2]) - (p.v[2] * q.v[1]);
	v[1] = (p.v[2] * q.v[0]) - (p.v[0] * q.v[2]);
	v[2] = (p.v[0] * q.v[1]) - (p.v[1] * q.v[0]);
}

void GLvector::Clamp(float min, float max)
{
	if (v[0] > max || v[0] < min)
		v[0] = 0;
	if (v[1] > max || v[1] < min)
		v[1] = 0;
	if (v[2] > max || v[2] < min)
		v[2] = 0;   
}

void GLvector::RotateX(float amnt, GLvector &dest)
{
   float s = GLSin(amnt);
   float c = GLCos(amnt);
   float y = v[1];
   float z = v[2];

   dest[0] = v[0];
   dest[1] = (y * c) - (z * s);
   dest[2] = (y * s) + (z * c);
}

void GLvector::RotateY(float amnt, GLvector &dest)
{
   float s = GLSin(amnt);
   float c = GLCos(amnt);
   float x = v[0];
   float z = v[2];

   dest[0] = (x * c) + (z * s);
   dest[1] = v[1];
   dest[2] = (z * c) - (x * s);
}

void GLvector::RotateZ(float amnt, GLvector &dest)
{
   float s = GLSin(amnt);
   float c = GLCos(amnt);
   float x = v[0];
   float y = v[1];

   dest[0] = (x * c) - (y * s);
   dest[1] = (y * c) + (x * s);
   dest[2] = v[2];
}