Rnd help please

[slenkar]

heres my code

Code:

POKE Uinteger 23675, @MyUdgBlock
randomize
BORDER 7 : PAPER 7 : INK 0 : CLS
  PRINT AT 3,13 ; PAPER 1 ; INK 7 ; "BattleField"
  PRINT AT 5,9 ; PAPER 7 ; INK 0 ; "Q - Up"
  PRINT AT 6,9 ; PAPER 7 ; INK 0 ; "A - Down"
  PRINT AT 7,9 ; PAPER 7 ; INK 0 ; "O - Left"
  PRINT AT 8,9 ; PAPER 7 ; INK 0 ; "P - Right"
  PRINT AT 9,9 ; PAPER 7 ; INK 0 ; "M - Select"

  PRINT AT 10,3 ; PAPER 7 ; INK 0 ; "You have to select units"
  PRINT AT 11,3 ; PAPER 7 ; INK 0 ; "to fight the enemy units"
  PRINT AT 15,3 ; PAPER 7 ; INK 0 ; "Press any key to start"

60  LET j$ = INKEY$
  IF j$ = "" THEN GOTO 60: END IF

  Function byterndrange (first As uByte, last As uByte) As uByte
    return Rnd * (last - first) + first
End Function
paper 4
cls
  BORDER 4: INK 0
  
for x=0 to 200
plot  byterndrange(0,255),byterndrange(0,192)
next



Dim BlueFactoryX (6) as uByte
Dim BlueFactoryY (6) as uByte
For x =0 to 5
BlueFactoryX(x)  = byterndrange(1,9)
BlueFactoryY(x)  = byterndrange(1,24)
Next

dim RedFactoryX (6) as uByte
dim RedFactoryY (6) as uByte

For x =0 to 5
RedFactoryX(x)  = byterndrange(28,32)
RedFactoryY(x)  = byterndrange(1,24)
Next


drawFactories()

sub drawFactories()
for x =0 to 5
ink 1
print at BlueFactoryX(x), BlueFactoryY(x); CHR$(144)
ink 2
print at RedFactoryX(x), RedFactoryY(x); CHR$(144)

next
End sub


STOP : REM Avoid execution to enter this zone
MyUdgBlock: REM a simple Label; @Label returns it's memory address
ASM
incbin "factory.BIN"
END ASM

When I draw random dots the rnd function works fine,
but when I draw factories at random positions it doesnt turn out right

I am trying to draw the red ones on the right side of the screen but they end up on the left
the blue ones are all over the screen

[boriel]

You're overflowing your screen: SINCLAIR Basic PRINT AT uses Y, X coordinates (row, column)
I've reversed them in your listing and it seems to be working ok. Since this is a compiled program, by default it won't check your screen overflows (e.g. "OUT of Screen error"), but with the flag (NOT YET IMPLEMENTED) --debug-screen it will stop when this happens.

There are more checkers already done:
--debug-array Will raise a "Subscript out of range" if you access an non-existing array-cell
--debug-memory Will raise an "Out of memory error" in case the program run out of mem.

The idea is: If you suspect your program has an error, enable the checkers and tests it. Once your program runs ok, compile again without your check flags (faster and less memory required)

Tip: PRINT ... ; is faster than PRINT ... , because the former doesn't need to print a newline. So use PRINT ... ; whenever possible. Also for legibility, you can use PRINT "\A" instead of PRINT CHRS$(144) (the compiled code is the same, though);

[slenkar]

thanks for the fix

PRINT ... ; is faster than PRINT ... ,

im not sure what this means,

like this?
Print y,x;
print y,x,

[boriel]

thanks for the fix

PRINT ... ; is faster than PRINT ... ,

im not sure what this means,

like this?
Print y,x;
print y,x,

No, this way:

Code:

PRINT a$; : REM Faster than PRINT a$

When you use PRINT, by default it prints a NEW LINE (carriage return) if no semicolon is used. So use semicolon ( as it's slightly faster (specially during in-game prints)

[slenkar]

ok thanks for that

[boriel]

I've just uploaded a new revision 1.2.7-r2096. Please download and test! It has some bugfixes so the --debug-array and the --debug-memory works ok again. If you run your program with --debug-array it seems to work ok, but sometimes an "OUT of Screen" is returned. So check screen boundaries.