rounding
Table of Contents
Rounding
Introduction
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.
Rounding modes
There are four rounding modes:
trunc– zeroes the fractional part of the numberfloor– rounds the number downceil– round the number upround– 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 |
Functions
Every rounding mode is available as two functions:
- Functions without the
iprefix return a fixed, e.g.floor(2.3) == 2.0. - Functions with the
iprefix 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: 2019/08/26 21:02 by korshun