unsigned long* los_blockrays = NULL;
unsigned long* dead_rays     = NULL;
unsigned long* smoke_rays    = NULL;

// These store all unique (in terms of footprint) full rays.
// Fullrays and raylengths are of equal size. The footprint
// of fullray[i] consists of raylengths[i] cells, whose
// coordinates are stored in ray_coord_{x,y} after the
// coordinates of fullray[i-1].
// These are filled during precomputation (_register_ray).
std::vector<ray_def> fullrays;
std::vector<int> raylengths;

// These store certain unique subsequences of ray_coord_{x,y}.
// Filled during precomputation (_create_blockrays)

std::vector<int> raylengths;
std::vector<ray_def> fullrays;

// 3D bit array indexed by x coord, y coord, cellray index.
// Bit los_blockrays[x][y][i] is set iff a wall at (x,y) blocks
// the cellray starting at compressed_ray_{x,y}[i].
unsigned long* los_blockrays = NULL;

// Temporary arrays used in losight() to track which rays
// are blocked or have seen a smoke cloud.
// Allocated when doing the precomputations.
unsigned long* dead_rays     = NULL;
unsigned long* smoke_rays    = NULL;

bool _get_bit_in_long_array( const unsigned long* data, int where )

bool _get_bit_in_long_array(const unsigned long* data, int where)

static void _set_bit_in_long_array( unsigned long* data, int where )

static void _set_bit_in_long_array(unsigned long* data, int where)

bool double_is_zero( const double x )

bool double_is_zero(const double x)

                _set_bit_in_long_array( inptr, j + cur_offset );

                _set_bit_in_long_array(inptr, j + cur_offset);