automatic rounding on integer casting? wtf!

Author

Message

Phaelax

DBPro Master

21

Years of Service

User Offline

Joined: 16th Apr 2003

Location: Metropia

Posted: 5th Jan 2016 09:15

Link

Just wasted 2 hours tracking this down. Sometimes I got proper grid coordinates, sometimes not. I'm used to every other language on the planet simply dropping the decimal when I assign a float to an integer, DB included. Why in the heck does AppGameKit round it?

+ Code Snippet

x = (ix#-MAP_OFFSET_X) / 64
y = (iy#-MAP_OFFSET_Y) / 32

"I like offending people, because I think people who get offended should be offended." - Linus Torvalds

Back to top

Profile PM Email Website

BatVink

Moderator

21

Years of Service

User Offline

Joined: 4th Apr 2003

Location: Gods own County, UK

Posted: 5th Jan 2016 10:22

Link

I'd never noticed that before, but you are right!
I'm sure it didn't work that way previously. But I just checked V1.08 and the behaviour is the same. I will have to add floor() to my calculations.
Anyone know if DBP behaves the same way?

+ Code Snippet

// set window properties
SetWindowTitle( "Integer Rounding" )
SetWindowSize( 1440, 900, 0 )
SetVirtualResolution(1440,900)

txt = CreateText("Integer Rounding")
setTextSize(txt,30)
SetTextPosition(txt, 10, 10)

do
	print("")
	print("")
	for n = 0 to 10
			x# = 10.0 + (n * 1.1)
			result = x# / 10
			print(str(x#,1) + " : " + str(result))
	next n
	sync()
loop

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Quidquid latine dictum sit, altum sonatur
TutCity is being rebuilt

Back to top

Profile PM Email

Markus

Valued Member

20

Years of Service

User Offline

Joined: 10th Apr 2004

Location: Germany

Posted: 5th Jan 2016 11:31 Edited at: 5th Jan 2016 11:35

Link

yo. thats uncommon.
result is 0 and 1

otherwise often there was add a 0.5 for a nearest conversion and here we not need it.

+ Code Snippet

do

	if GetPointerPressed() then end

		a=0.2
		b=0.8
		
		print(a)
		print(b)

		sync()
loop
end

AGK (Steam) V2.0.16 : Windows 10 Pro 64 Bit : AMD (15.30.1025) Radeon R7 265 : Mac mini OS X 10.10 (Yosemite)

Back to top

Profile PM Email

Digital Awakening

AGK Developer

22

Years of Service

User Offline

Joined: 27th Aug 2002

Location: Sweden

Posted: 5th Jan 2016 15:09

Link

I remember the old discussion we had on this topic. IIRC that's standard for BASIC. AppGameKit have always done that.

You should use:
integer Trunc( a )
"Returns the integer part of a float value with no rounding either way. "

If you want:
integer Floor( a )
"Rounds a float to the next lowest integer. This differs from Trunc when using negative numbers, Trunc( -1.6 ) is -1 but Floor( -1.6 ) is -2. "

Back to top

Profile PM Website

Sorry your browser is not supported!

AppGameKit Classic Chat / automatic rounding on integer casting? wtf!