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)`

Table of Contents

Rounding

Introduction

Rounding modes

Functions