INP: Difference between revisions
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(Created page with "INP returns a value from a computer register or port values at a specified physical address. {{PageSyntax}} : {{Parameter|i}} = INP({{Parameter|address}}) * '''QB64 has limited access to registers. VGA memory and registers are emulated.''' * Address can be a decimal or hexadecimal INTEGER value. * INP reads directly from a register or port address. * It does not require a DEF SEG memory segment address like PEEK or POKE do. * Reads color p...") |
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{{PageExamples}} | {{PageExamples}} | ||
''Example 1:'' Reading the current RGB color settings used in a bitmap to an array. | ''Example 1:'' Reading the current RGB color settings used in a bitmap to an array. | ||
{{CodeStart}} | {{CodeStart}} | ||
SCREEN 12 | SCREEN 12 | ||
{{Cl|DIM}} Colors%(47) | {{Cl|DIM}} Colors%(47) | ||
| Line 21: | Line 21: | ||
{{Cl|FOR...NEXT|FOR}} i = 0 {{Cl|TO}} 47 | {{Cl|FOR...NEXT|FOR}} i = 0 {{Cl|TO}} 47 | ||
Colors%(i) = {{Cl|INP}}(&H3C9) ' moves to next color attribute every 3 loops | Colors%(i) = {{Cl|INP}}(&H3C9) ' moves to next color attribute every 3 loops | ||
{{Cl|NEXT}} | {{Cl|NEXT}} | ||
{{CodeEnd}} | {{CodeEnd}} | ||
''Example 2:'' Reading the keyboard Scan Codes as an alternative to [[INKEY$]] | ''Example 2:'' Reading the keyboard Scan Codes as an alternative to [[INKEY$]] | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cl|DO}}: {{Cl|SLEEP}} | {{Cl|DO}}: {{Cl|SLEEP}} | ||
scancode% = {{Cl|INP}}(&H60) | scancode% = {{Cl|INP}}(&H60) | ||
a$ = {{Cl|INKEY$}} ' clears keyboard buffer | a$ = {{Cl|INKEY$}} ' clears keyboard buffer | ||
{{Cl|PRINT}} scancode%; | {{Cl|PRINT}} scancode%; | ||
{{Cl|LOOP}} {{Cl|UNTIL}} scancode% = 1 ' [ESC] keypress exit | {{Cl|LOOP}} {{Cl|UNTIL}} scancode% = 1 ' [ESC] keypress exit | ||
{{CodeEnd}} | {{CodeEnd}} | ||
''Example 3:'' A simple ping pong game using an array function to read multiple keys for two players. | ''Example 3:'' A simple ping pong game using an array function to read multiple keys for two players. | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cl|DEFINT}} A-Z | {{Cl|DEFINT}} A-Z | ||
{{Cl|SCREEN}} 12 | {{Cl|SCREEN}} 12 | ||
| Line 101: | Line 101: | ||
K$ = {{Cl|INKEY$}} | K$ = {{Cl|INKEY$}} | ||
ScanKey% = keyflags%(scancode%) | ScanKey% = keyflags%(scancode%) | ||
{{Cl|END FUNCTION}} | {{Cl|END FUNCTION}} | ||
{{CodeEnd}} | {{CodeEnd}} | ||
: ''Note:'' [[_KEYDOWN]] can be used to read multiple keys simultaneously and is the '''recommended practice'''. | : ''Note:'' [[_KEYDOWN]] can be used to read multiple keys simultaneously and is the '''recommended practice'''. | ||
{{PageSeeAlso}} | {{PageSeeAlso}} | ||
* [[OUT]] {{text|(write to register)}}, [[PEEK]] {{text|(read memory)}} | * [[OUT]] {{text|(write to register)}}, [[PEEK]] {{text|(read memory)}} | ||
* [[INKEY$]], [[_KEYHIT]], [[_KEYDOWN]] | * [[INKEY$]], [[_KEYHIT]], [[_KEYDOWN]] | ||
Revision as of 01:49, 23 January 2023
INP returns a value from a computer register or port values at a specified physical address.
Syntax
- i = INP(address)
- QB64 has limited access to registers. VGA memory and registers are emulated.
- Address can be a decimal or hexadecimal INTEGER value.
- INP reads directly from a register or port address.
- It does not require a DEF SEG memory segment address like PEEK or POKE do.
- Reads color port intensity settings after OUT &H3C7, attribute sets the starting attribute read mode.
Examples
Example 1: Reading the current RGB color settings used in a bitmap to an array.
SCREEN 12 DIM Colors%(47) OUT &H3C7, 0 ' set color port for INP reads at attribute 0 to start FOR i = 0 TO 47 Colors%(i) = INP(&H3C9) ' moves to next color attribute every 3 loops NEXT |
Example 2: Reading the keyboard Scan Codes as an alternative to INKEY$
DO: SLEEP scancode% = INP(&H60) a$ = INKEY$ ' clears keyboard buffer PRINT scancode%; LOOP UNTIL scancode% = 1 ' [ESC] keypress exit |
Example 3: A simple ping pong game using an array function to read multiple keys for two players.
DEFINT A-Z SCREEN 12 DIM ball%(100) ' Set aside enough space to hold the ball sprite CIRCLE (4, 3), 4, 4 PAINT (4, 3), 12, 4 ' Draw a filled circle and fill for ball GET (0, 0)-(8, 7), ball%(0) ' Get the sprite into the Ball% array begin: xmin = 10: ymin = 10 xmax = 630: ymax = 470 x = 25: y = 25 dx = 1: dy = 1 LTpos = 50: RTpos = 50 DO: _LIMIT 100 'adjust higher for faster CLS IF ScanKey%(17) THEN LTpos = LTpos - 1 IF ScanKey%(31) THEN LTpos = LTpos + 1 IF ScanKey%(72) THEN RTpos = RTpos - 1 IF ScanKey%(80) THEN RTpos = RTpos + 1 PRINT "Player 1 : "; ponescore; " Player 2 : "; ptwoscore IF x > xmax - 15 AND y >= RTpos AND y <= RTpos + 100 THEN dx = -1 ELSEIF x > xmax THEN ponescore = ponescore + 1 GOSUB begin END IF IF x < xmin + 15 AND y >= LTpos AND y <= LTpos + 100 THEN dx = 1 ELSEIF x < xmin THEN ptwoscore = ptwoscore + 1 GOSUB begin END IF IF y > ymax - 5 THEN dy = -1 IF y < ymin + 5 THEN dy = 1 ' Display the sprite elsewhere on the screen x = x + dx y = y + dy PUT(x, y), ball%(0) LINE (20, LTpos)-(20, LTpos + 100) LINE (620, RTpos)-(620, RTpos + 100) _DISPLAY 'shows completed screen every call LOOP UNTIL ScanKey%(1) END FUNCTION ScanKey% (scancode%) STATIC Ready%, keyflags%() IF NOT Ready% THEN REDIM keyflags%(0 TO 127): Ready% = -1 i% = INP(&H60) 'read keyboard states IF (i% AND 128) THEN keyflags%(i% XOR 128) = 0 IF (i% AND 128) = 0 THEN keyflags%(i%) = -1 K$ = INKEY$ ScanKey% = keyflags%(scancode%) END FUNCTION |
- Note: _KEYDOWN can be used to read multiple keys simultaneously and is the recommended practice.
See also
- OUT (write to register), PEEK (read memory)
- INKEY$, _KEYHIT, _KEYDOWN
- Bitmaps, Scancodes (keyboard)
- Port Access Libraries (COM or LPT registers)
External Links