ray plane intersection by SUNSTAR

bool distRayPlane(vec3 vRayOrigin, vec3 vRayVector, vec3 vPlaneNormal, float fPlaneDist, vec3 vIntersection) {     float fCosAlpha;     float fDeltaDist;     float fRayDist;     fCosAlpha = DotProduct(vRayVector ,  vPlaneNormal);     if (fCosAlpha==0) return false; //ray is parallel to the plane     fDeltaDist = fPlaneDist - DotProduct(vRayOrigin,vPlaneNormal);     fRayDist = fDeltaDist/fCosAlpha;     vIntersection = vRayOrigin + ScalarProduct(vRayVector, fRayDist);     return true; }