rounding

ACSUtils provides a full set of functions to round fixed-point numbers to integers.

Current GZDoom provides built-in functions floor, ceil and round, but these functions aren't available in Zandronum 3.0 and **silently return 0** there, because all unimplemented built-in ACS functions return 0.

Before using ACSUtils, rename either the built-in functions (by editing `zspecial.acs`

) or the ACSUtils functions (by editing `acsutils.acs`

) to something else. Otherwise, ACSUtils won't compile.

There are four rounding modes:

`trunc`

– zeroes the fractional part of the number`floor`

– rounds the number down`ceil`

– round the number up`round`

– rounds the number to the closest integer

A table that demonstrates the differences between rounding modes:

x | round(x) | floor(x) | ceil(x) | trunc(x) |
---|---|---|---|---|

1.3 | 1 | 1 | 2 | 1 |

1.5 | 1 or 2 | 1 | 2 | 1 |

1.8 | 2 | 1 | 2 | 1 |

-1.3 | -1 | -2 | -1 | -1 |

-1.5 | -2 or -1 | -2 | -1 | -1 |

-1.8 | -2 | -2 | -1 | -1 |

Every rounding mode is available as two functions:

- Functions without the
`i`

prefix return a fixed, e.g.`floor(2.3) == 2.0`

. - Functions with the
`i`

prefix return an int, e.g.`ifloor(2.3) == 2`

.

Mode | fixed result | int result |
---|---|---|

floor | `fixed floor(fixed x)` | `int ifloor(fixed x)` |

ceil | `fixed ceil(fixed x)` | `int iceil(fixed x)` |

round | `fixed round(fixed x)` | `int iround(fixed x)` |

trunc | `fixed trunc(fixed x)` | `int itrunc(fixed x)` |

rounding.txt · Last modified: 2019/04/20 20:12 by korshun