Difference between revisions of "Bitwise Operators"

From GiderosMobile
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'''Supported platforms:''' [[File:Platform android.png]][[File:Platform ios.png]][[File:Platform mac.png]][[File:Platform pc.png]]<br/>
 
'''Supported platforms:''' [[File:Platform android.png]][[File:Platform ios.png]][[File:Platform mac.png]][[File:Platform pc.png]]<br/>
 
'''Available since:''' Gideros 2017.10<br/>
 
'''Available since:''' Gideros 2017.10<br/>
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=== See also ===
'''See also: https://www.lua.org/pil/3.3.html'''
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'''https://www.lua.org/pil/3.3.html'''
 
 
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| style="width: 50%; vertical-align:top;"|
 
=== Methods ===
 
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=== Events ===
 
=== Constants ===
 
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{{GIDEROS IMPORTANT LINKS}}
 
{{GIDEROS IMPORTANT LINKS}}

Revision as of 01:22, 30 November 2022

Supported platforms: Platform android.pngPlatform ios.pngPlatform mac.pngPlatform pc.png
Available since: Gideros 2017.10

Description

Bitwise operators to manipulate numbers.

a | b     Bitwise 'a OR b'.
a & b     Bitwise 'a AND b'.
a ~ b     Bitwise 'a XOR b'.
a << b   Bitwise shift 'a' by 'b' left.
a >> b   Bitwise shift 'a' by 'b' right.
~ a     Bitwise 'NOT a'.

Examples

Set joypad switches

if k==KeyCode.UP then joypad=joypad|0b001000
elseif k==KeyCode.DOWN then joypad=joypad|0b000100
elseif k==KeyCode.LEFT then joypad=joypad|0b000010
elseif k==KeyCode.RIGHT then joypad=joypad|0b000001
end

Clear joypad switches

if k==KeyCode.UP then joypad=joypad&0b0111
elseif k==KeyCode.DOWN then joypad=joypadRGUDLR&0b1011
elseif k==KeyCode.LEFT then joypad=joypadRGUDLR&0b1101
elseif k==KeyCode.RIGHT then joypad=joypadRGUDLR&0b1110
end

Move in a direction based on joystick switches (using above examples)

local deltaX={0,-1,1,0,0,-1,1,0,0,-1,1,0,0,-1,1,0}
local deltaY={0,0,0,0,1,1,1,1,-1,-1,-1,-1,0,0,0,0}
x=x+deltaX[joypad+1]
y=y+deltaY[joypad+1]

Debounce bits, eg joypad switches

debouncedJoypad=(joypad~joypadOld)&joypad
joypadOld=joypad

See also

https://www.lua.org/pil/3.3.html