OpenGL (SDL,C++) - ray tracing - functions.h

//http://www.youtube.com/user/thecplusplusguy
//watch the video for explonation
//ray-sphere and ray-plane collision detection.
//if you find a bug, let me know
#include <SDL/SDL.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <cstdlib>
#include <vector>
#include <string>
#include <algorithm>
#include <fstream>
#include <cstdio>
#include <iostream>
#include <cmath>
#include "objloader.h"
#ifndef FUNCTION_H
#define FUNCTION_H

void drawCube(float size);
void drawSkybox(float size);
void initskybox();
void killskybox();
void lockCamera();
void moveCamera(float,float);
void moveCamerraUp(float,float);
void Control(float,float,bool);
void UpdateCamera();
unsigned int loadTexture(const char*);
bool raysphere(float xc,float yc, float zc,float xd,float yd, float zd,float xs,float ys, float zs,float r);
bool rayplane(float nx,float ny,float nz,float xs,float ys,float zs,float xd,float yd,float zd,coordinate p1,coordinate p2,coordinate p3,coordinate p4);
float trianglearea(coordinate p1,coordinate p2,coordinate p3);
#endif