www.pudn.com > simpleraytracer_v1_0.zip > raysphere.cpp

/*=================================================================== 
 
   
  digital liberation front 2002 
   
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 /______/\  |______|    /\______\   
|       \ \ |      |   / /       |     
|	      \| |      |  |/         |   
|_____    \ |      |_ /    ______|        
 ____|    | |      |_||    |_____           
     |____| |________||____|                 
            
 
 
 
Code by Nicholas Chapman[/ Ono-Sendai] 
nickamy@paradise.net.nz 
 
You may use this code for any non-commercial project, 
as long as you do not remove this description. 
 
You may not use this code for any commercial project. 
====================================================================*/ 
#include "raysphere.h" 
 
#include "ray.h" 
 
 
 
	//returns neg num if object not hit by the ray 
float RaySphere::getDistanceUntilHit(const Ray& ray) const 
{ 
	const Vec3 raystarttosphere = this->centerpos - ray.startpos; 
 
	const float dist_to_rayclosest = dotProduct(raystarttosphere, ray.unitdir); 
 
 
	//----------------------------------------------------------------- 
	//check if center of sphere lies behind ray startpos (in dir of ray) 
	//----------------------------------------------------------------- 
	if(dist_to_rayclosest < 0.0f)//will think of rays as having infinite length || q_closest > ray.length) 
		return -666.0f; 
 
 
	const float sph_cen_to_ray_closest_len2 = raystarttosphere.length2() -  
		dist_to_rayclosest*dist_to_rayclosest; 
 
	//----------------------------------------------------------------- 
	//ray has missed sphere? 
	//----------------------------------------------------------------- 
	if(sph_cen_to_ray_closest_len2 > this->radius_squared) 
		return -666.0f; 
 
 
	//ray has hit sphere... 
	 
	 
	return dist_to_rayclosest - sqrt(this->radius_squared - sph_cen_to_ray_closest_len2); 
} 
 
 
const Vec3 RaySphere::getNormalForPos(const Vec3& point) const  
{  
	return (point - centerpos) * recip_radius; 
}