SBPE what I've got so far

' SBPE - SmileBASIC Platforming Engine
' ====================================

' Copyright © Nitai Sasson
' All rights reserved

' DO NOT UPLOAD THIS FILE
' OR ANY DERIVATIVES THEREOF
' TO SMILEBOOM SERVERS WITHOUT
' MY EXPLICIT PERMISSION

GOSUB @INIT
'TERMINATE < just for notepad++ to not bug out
END

@INIT
    DIM TOINDEX%[512], TOMNG%[0], EMPTYINDEX%[0]    ' Back-and-forth between internal indexing of sprites and the actual management numbers.
    FILL TOINDEX%, -1    ' Start with no sprites defined

    DIM X%[0], Y%[0], VX%[0], VY%[0], SPMODE%[0] ' vaiables for each sprite
RETURN

COMMON DEF SBPE_SPMODE MNGID%, TYPE%
    ' Available types:
    ' -1 = off (remove from SBPE)
    ' 0 = ghost - goes through walls
    ' 2 = sticky

    IF TYPE% == -1 THEN
        REMOVE_MNG MNGID%
        RETURN
    ENDIF

    VAR INDX% = TOINDEX%[MNGID%]
    IF INDX% == -1 THEN
        INDX% = NEWINDEX%(MNGID%)
    ENDIF

    SPMODE%[INDX%] = TYPE%
END


DEF REMOVE_MNG MNGID%
    VAR INDX% = TOINDEX%[MNGID%]
    IF INDX% == -1 THEN RETURN ' Already removed
    TOMNG%[INDX%] = -1  ' Remove from internal index
    SPMODE%[INDX%] = -1 ' Used in internal loop
    PUSH EMPTYINDEX%, INDX% ' Remember unused index
    TOINDEX%[MNGID%] = -1   ' Remove from management index
END

DEF REMOVE_INDEX INDX%  ' I wonder if I'll need this
    VAR MNGID% = TOMNG%[INDX%]
    IF MNGID% == -1 THEN RETURN ' Already removed
    TOINDEX%[MNGID%] = -1   ' Remove from management index
    PUSH EMPTYINDEX%, INDX% ' Remember unused index
    TOMNG%[INDX%] = -1  ' Remove from management index
    SPMODE%[INDX%] = -1 ' Used in internal loop
END

DEF NEWINDEX%(MNGID%)
    VAR INDX%
    IF LEN(EMPTYINDEX%) == 0 THEN
        INDX% = LEN(TOMNG)
        PUSH TOMNG%, MNGID%
        PUSH X%, 0
        PUSH Y%, 0
        PUSH VX%, 0
        PUSH VY%, 0
        PUSH SPMODE%, 0
    ELSE
        INDX% = POP(EMPTYINDEX%)
        TOMNG%[INDX%] = MNGID%
        X%[INDX%] = 0
        Y%[INDX%] = 0
        VX%[INDX%] = 0
        VY%[INDX%] = 0
        SPMODE%[INDX%] = 0
    ENDIF
    TOINDEX%[MNGID%] = INDX%
    RETURN INDX%
END