OpenEuphoria

Re: Bad Co-ordinates

• Posted by Brian Broker <bkb at CNW.COM> Sep 26, 2000
• 486 views

On Tue, 26 Sep 2000 16:34:52 -0700, Thomas wrote:

>Well, I've written a program with a lot of help from Brian and it's
>still.....broken. My fault really. Anyways, I've attatched it and the
>problems are..
>
>1. If you move left to the limits, it crashes

Then don't let it move left to the limits...

>2. If you go too far right, well, it goes to far (past screen limits) and
>you can't go left. I know what the problem is, but the solution evades
>me.

Check your logic...  you rather mangled the structure of the code I gave
you and that makes it more difficult to find errors in logic.

>3. There seems to be a green border in 256 mode......

That is a result of using 'all_palette'.  I don't remember which palette
index corresponds to the border color, but you are changing it from black
to green when you use 'all_pallete'.

>PS. How d'you like my jet?

Nice jet...


Try this:
---------

include image.e
include keyread.e
include graphics.e

---lalala

constant
  -- Scan Codes:
  ESC = 1,
  UP = 328,
  DOWN = 336,
  LEFT = 333,
  RIGHT = 331,

  -- Indexes to enhance readability of code:
  X = 1,
  Y = 2,

  MoveStep = 5,       -- number of pixels to move jet on key press
  BmpSize = {63,76},  -- size of bitmap
  MAX = {640,400}     -- size of screen in mode 256


integer gmode
sequence jetmove,desc
integer ix,iy
ix=200
iy=300

use_vesa(1)
gmode=graphics_mode(256)

jetmove=read_bitmap("jetmove.BMP")
all_palette(jetmove[1]/4)
text_color(10)
puts(1,"arrows move, ESC quits")

procedure wait( atom n )
  n += time()
  while time() < n do
    -- nothing
  end while
end procedure

while 1 do
  desc = get_keys()
  position(2,1)
  ? desc
  display_image({ix,iy},jetmove[2])  -- show jet
  if length( desc ) > 0 then         -- a key is being pressed
    if desc[1] = ESC then
        abort(0)
    elsif desc[1]=LEFT then
      if ix < MAX[X]-BmpSize[X] then
        ix += MoveStep
      end if
    elsif desc[1]=RIGHT then
      if ix > 0 then
        ix -= MoveStep
      end if
    elsif desc[1]=UP then
      if iy > 0  then
        iy -= MoveStep
      end if
    elsif desc[1]=DOWN then
       if iy < MAX[Y]-BmpSize[Y] then
         iy += MoveStep
       end if
    end if
    wait(0.0005)
  end if
end while
-- Brian