__device void camera_sample(KernelGlobals *kg, int x, int y, float filter_u, float filter_v, float lens_u, float lens_v, Ray *ray)
{
/* pixel filter */
__device void camera_sample(KernelGlobals *kg, int x, int y, float filter_u, float filter_v, float lens_u, float lens_v, Ray *ray)
{
/* pixel filter */