ReturnOriginals

   10 REM ******************************
   20 REM *        AGON LIGHT 2        *
   30 REM *     BBC BASIC TEMPLATE     *
   40 REM *      BBC BASIC MODE 8      *
   50 REM *    C/W RESET ORIG SCREEN   *
   60 REM *      BY STEVE LOVEJOY      *
   70 REM ******************************
   80 :
   90 REM MAIN SETUP.
  100 CLEAR : REM clear memory.
  110 :
  120 PROC_LOAD_VARS             : REM CALL LOAD_VARS.
  130 PROC_GET_ORIGINALS         : REM CALL GET_ORIGINALS.
  140 PROC_INITIALIZE_SCREEN     : REM CALL INIT_SCREEN.
  150 PROC_MAIN_LOOP             : REM CALL MAIN_LOOP.
  160 :
 1000 DEF PROC_MAIN_LOOP         : REM ** MAIN LOOP **
 1010 COLOUR COL_YELLOW%         : REM CHANGE text colour.
 1020 PRINT TAB(24,20)"HELLO WORLD!"    : REM PRINT at (x,y).
 1030 PRINT TAB(22,22)"PRESS X TO EXIT" : REM PRINT at (x,y).
 1040 A%=INKEY(0)                : REM GET keyboard input.
 1050 IF A%=120 OR A%=88 THEN PROC_CHECK_EXIT : REM press X to exit.
 1060 PROC_MAIN_LOOP             : REM loop back to start of MAIN_LOOP.
 3000 ENDPROC : REM END PROC_MAIN_LOOP.
 3010 :
 4000 DEF PROC_GET_ORIGINALS     : REM ** GET_ORIGINALS **
 4010 OM% = FN_GETBYTE_VDP(&27)  : REM GET original Screen Mode.
 4020 VDU 23,230,255,255,255,255,255,255,255,255 : REM CREATE new filled char with original colours.
 4030 PRINT TAB(0,0);CHR$(230);  : REM PRINT new char top left.
 4040 OTFC% = POINT(4,1015)      : REM GET original text fg colour.
 4050 VDU 127                    : REM DELETE new char to get bg colour.
 4060 OTBC% = POINT(4,1015)      : REM GET original text bg colour.
 4070 ENDPROC : REM END PROC_GET_ORIGINALS.
 4080 :
 5500 DEF PROC_INITIALIZE_SCREEN : REM ** INITIALIZE_SCREEN **
 5510 MODE 0                     : REM SETS new screen mode.
 5520 CLS                        : REM clear text screen.
 5530 CLG                        : REM clear graphics screen.
 5540 PROC_HIDE_CURSOR
 5550 ENDPROC : REM END PROC_INITIALIZE_SCREEN.
 5560 :
 6000 DEF PROC_HIDE_CURSOR       : REM ** HIDE_CURSOR **
 6010 VDU 23,1,0;0;0;0;
 6020 ENDPROC
 6030 :
 6040 DEF PROC_SHOW_CURSOR       : REM ** SHOW_CURSOR **
 6050 VDU 23,1,1;0;0;0;
 6060 ENDPROC
 6070 :
 8000 DEF PROC_LOAD_VARS : REM ** LOAD_VARS **
 8010 REM NAME colours, add 128 for background.
 8020 COL_BLACK% = 0
 8030 COL_RED% = 1
 8040 COL_GREEN% = 2
 8050 COL_YELLOW% = 3
 8060 COL_BLUE% = 4
 8070 COL_MAGENTA% = 5
 8080 COL_CYAN% = 6
 8090 COL_WHITE% = 7
 8100 COL_INTRED% = 9
 8110 COL_INTGREEN% = 10
 8120 COL_INTYELLOW% = 11
 8130 COL_INTBLUE% = 12
 8140 COL_INTMAGENTA% = 13
 8150 COL_INTCYAN% = 14
 8160 COL_INTWHITE% = 15
 8500 ENDPROC : REM END LOAD_VARS.
 8510 :
 8600 DEF PROC_CHECK_EXIT : REM ** CHECK EXIT **
 8610 PRINT TAB(19,24);"Quit? Press Y to confirm"
 8620 Y$=GET$
 8630 IF Y$="y" OR Y$= "Y" THEN PROC_RESET_ORIGINALS
 8640 ENDPROC : REM END PROC_CHECK_EXIT
 8650 :
 9000 DEF PROC_RESET_ORIGINALS : REM ** RESET_ORIGINALS **
 9010 VDU 20               : REM RESET logical colours to default colours.
 9020 MODE OM%             : REM SET original screen mode.
 9030 COLOUR OTFC%         : REM SET original text fg colour.
 9040 COLOUR OTBC% + 128   : REM SET original text bg colour.
 9050 PROC_SHOW_CURSOR     : REM reset cursor.
 9060 CLS                  : REM clear screen to SET original colours.
 9070 P."GOODBYE!"         : REM print to screen to test restore function.
 9080 END                  : REM END program.
 9090 REM ENDPROC : REM END RESET_ORIGINALS
 9100 :
 9500 REM GET sysvar function for original screen mode.
 9510 DEF FN_GETBYTE_VDP(V%): A% = &A0: L%=V%: = USR(&FFF4)