光线与球的求交代码
//
-------------------------------------------------------------------------
eiBool eiSphere::intersect(eiRay
*
ray, eiObject
*
po, eiFloat
&
oldt, eiPrimitive
* &
ret_pri, eiFloat
*
cust_data, HitParam
*
hparam)
{ if( oldt == 0.0f || ray_box( ray->src, hparam->hitPoint ) { //compute intersecting point eiVector oc = add( ray->src, - center ); eiFloat oc_len = dist( oc ); if( oc_len > radius || po->material->doubleSide ) { eiFloat a = dot( ray->dir, ray->dir ); eiFloat b = 2.0f * dot( oc, ray->dir); eiFloat c = dot( oc, oc ) - RR; eiFloat dt = b * b - 4.0f * a * c; eiFloat t; if(a == 0.0f || dt < 0.0f) return false; else if(dt == 0.0f) { t = - b / a * 0.5f; if(t < 0.0f) return false; } else { a = 0.5f / a; eiFloat t1 = (- b + sqrtf( dt )) * a; eiFloat t2 = (- b - sqrtf( dt )) * a; if(t1 > 0.0f && t2 < 0.0f) t = t1; else if(t1 < 0.0f && t2 > 0.0f) t = t2; else if(t1 > 0.0f && t2 > 0.0f) t = (t1 < t2) ? t1 : t2; else return false; } eiVector tmpIntersection = add(ray->src, mulvf(ray->dir,t)); //affect shadow factor if(ray->type == RAY_SHADOW) hparam->shadow_factor *= 1.0f - po->material->opacity; //find nearest hit point if(oldt == 0.0f || t < oldt) { hparam->hitPoint = tmpIntersection; hparam->hitObj = po; ret_pri = this; oldt = t; //fill custom data return true; } } } return false;}
posted on
2005-07-28 22:16
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转载于:https://www.cnblogs.com/len3d/archive/2005/07/28/202305.html
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