Question about Functions - GameCreators Forum

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Captain IceT

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Joined: 21st Oct 2008

Location: Boat Murdered, and Im still laughing!

Posted: 21st Oct 2008 20:22

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Hello all!
I have actually been a member of this forum before, but I put down DBPro to work on other things, and I am now coming back. I have run into a bit of a problem using functions in my program.

The following works, I am able to use WASD to control the camera, smoothly moving by increments of 50, and turning 90 degrees.

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0

DONE = 0
REPEAT
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
UNTIL Done = 100
END

+ Code Snippet

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0


DONE = 0
REPEAT
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
UNTIL Done = 100
END

However, when I move the bulk of the control code to a function, called Player_Move(), It stops turning by 90 degrees, and moving in increments of 50, it seems like it cycles within my function until the timers have counted down before exiting. Any ideas how to prevent this?

Here is the code with the function:

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0

DONE = 0
REPEAT
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   Player_Move()
UNTIL Done = 100
END
FUNCTION Player_Move()
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
ENDFUNCTION

+ Code Snippet

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0


DONE = 0
REPEAT
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   Player_Move()
UNTIL Done = 100
END
FUNCTION Player_Move()
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
ENDFUNCTION

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Captain IceT

16

Years of Service

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Joined: 21st Oct 2008

Location: Boat Murdered, and Im still laughing!

Posted: 21st Oct 2008 23:13

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I think I answered my own question.

Turns out the variables I'm using have to be Global, as I think that it does not keep the value when I exit the function...

does that sound right?

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Captain IceT

16

Years of Service

User Offline

Joined: 21st Oct 2008

Location: Boat Murdered, and Im still laughing!

Posted: 21st Oct 2008 23:19

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Well it seems to be working better, but the camera seems to be turning further than 90 degrees now...

Here's my updated code:

Rem Project: Prog
Rem Created: 10/19/2008 11:48:21 PM

Rem ***** Main Source File *****

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
LOAD IMAGE "stacked_stone.jpg", WEB_STONE_WALL, 1
LOAD IMAGE "Stone_block.jpg", STONE_WALL, 1

GLOBAL Frwrd AS INTEGER
GLOBAL Bckwrd AS INTEGER
GLOBAL Turn_L AS INTEGER
GLOBAL Turn_R AS INTEGER
GLOBAL Strf_L AS INTEGER
GLOBAL Strf_R AS INTEGER

REM create Sky box
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Texture Object 1, Stone_Wall
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0

DONE = 0
REPEAT
   SET CURSOR 1,1
   PRINT Camera Angle X();", ";Camera Angle Y();", ";Camera Angle Z()
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   Player_Move()
UNTIL Done = 100
END

FUNCTION Player_Move()
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
ENDFUNCTION

+ Code Snippet

Rem Project: Prog
Rem Created: 10/19/2008 11:48:21 PM

Rem ***** Main Source File *****

#CONSTANT Menu = 1
GLOBAL Strafe_Left = 16
GLOBAL Strafe_Right = 18
GLOBAL Turn_Left = 30
GLOBAL Turn_Right = 32
GLOBAL Forward = 17
GLOBAL Backward = 31
#CONSTANT Flr = 50
#CONSTANT Ceiling = 100
#CONSTANT Wall = 150
#CONSTANT WEB_STONE_WALL = 1
#CONSTANT STONE_WALL = 2
LOAD IMAGE "stacked_stone.jpg", WEB_STONE_WALL, 1
LOAD IMAGE "Stone_block.jpg", STONE_WALL, 1

GLOBAL Frwrd AS INTEGER
GLOBAL Bckwrd AS INTEGER
GLOBAL Turn_L AS INTEGER
GLOBAL Turn_R AS INTEGER
GLOBAL Strf_L AS INTEGER
GLOBAL Strf_R AS INTEGER

REM create Sky box
MAKE OBJECT SPHERE 600, -810
COLOR OBJECT 600, RGB(0,0,0)

Make Object Cube 1, 50
Texture Object 1, Stone_Wall
Position Object 1, 0, 0, 50

REM make map
DIM Map(50,50)
FOR x = 1 TO 12
   FOR y = 1 TO 12
      Map(x,y) = 0
   NEXT y
NEXT x

START_X = 0: START_Y = 0: START_Z = 0:
POSITION CAMERA START_X, START_Z, START_Y
ROTATE CAMERA 0, 0, 0


DONE = 0
REPEAT
   SET CURSOR 1,1
   PRINT Camera Angle X();", ";Camera Angle Y();", ";Camera Angle Z()
   IF KEYSTATE(MENU) = 1 THEN DONE = 100
   Player_Move()
UNTIL Done = 100
END

FUNCTION Player_Move()
   IF KEYSTATE(Forward) = 1 AND Command = 0
      Frwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Backward) = 1 AND Command = 0
      Bckwrd = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Left) = 1 AND Command = 0
      Turn_L = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Turn_Right) = 1 AND Command = 0
      Turn_R = 90
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Left) = 1 AND Command = 0
      Strf_L = 50
      Command = 1
   ENDIF
   IF KEYSTATE(Strafe_Right) = 1 AND Command = 0
      Strf_R = 50
      Command = 1
   ENDIF
   IF Frwrd > 0
      MOVE CAMERA 1
      DEC Frwrd
      IF Frwrd = 0 THEN Command = 0
   ENDIF
   IF Bckwrd > 0
      MOVE CAMERA -1
      DEC Bckwrd
      IF Bckwrd = 0 THEN Command = 0
   ENDIF
   IF Turn_L > 0
      TURN CAMERA LEFT 1
      DEC Turn_L
      IF Turn_L = 0 THEN Command = 0
   ENDIF
   IF Turn_R > 0
      TURN CAMERA RIGHT 1
      DEC Turn_R
      IF Turn_R = 0 THEN Command = 0
   ENDIF
ENDFUNCTION

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IanM

Retired Moderator

22

Years of Service

User Offline

Joined: 11th Sep 2002

Location: In my moon base

Posted: 21st Oct 2008 23:27

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That's exactly right.

By default, all variables declared outside a function are not available within a function, and all variables declared within a function are local to that function and are not available outside of it.

+ Code Snippet

a as integer            ` Not global
global b as integer     ` Global

print "Initial values"
print "  a="; a
print "  b="; b

f1()
print "Values after calling f1()"
print "  a="; a
print "  b="; b

f2()
print "Values after calling f2()"
print "  a="; a
print "  b="; b

wait key
end

function f1()
   a = 1                ` Updates a local variable
   b = 1                ` Updates the global variable b
   print "Values within f1()"
   print "  a="; a
   print "  b="; b
endfunction

function f2()
   local b as integer
   b = 2                ` Updates the local variable b
   print "Values within f2()"
   print "  a="; a
   print "  b="; b
endfunction

I won't go into arrays, but just assume for now that they are automatically global. (Their behaviour seems different in 7.1 but that may have occurred in an earlier release)

[b]Utility plug-ins collection (updated 27/09/08) and
http://www.matrix1.demon.co.uk

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Captain IceT

16

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Joined: 21st Oct 2008

Location: Boat Murdered, and Im still laughing!

Posted: 21st Oct 2008 23:34

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Nevermind, I will quit bothering you good people with simple errors.

(I forgot one of the variables when I started declaring as global. If you add GLOBAL Command AS INTEGER, it works fine.)

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