OpenEuphoria

Re: PACER Graphics Demo Problem

• Posted by Lewis Townsend <keroltarr at HOTMAIL.COM> Oct 03, 2000
• 387 views

Hello CK, Mark,


>BTW, PACER.EX is Mark Akita's program. Seems Rob can run the code
>unaltered... Is that correct, Rob? If this is true, why would it break on
>my
>machine?
>
>I noticed in the PACER.EX code that
>
>     i1 = vesa_mode(640,480,16)
>
>is called prior to
>
>     clear_screen()
>
>So does vesa_mode not actually set the graphics mode?

I believe vesa_mode() DOES set teh graphics mode and it also
clears the screen (at least in my experience). clear_screen()
can ONLY work AFTER a graphics mode is set. There are 3
global variables in Neil.e that must be set before you can
do ANY useful sfuff:

SCREEN_W  -- screen width
SCREEN_H  --   "    height
Bits_Per_Pixel -- I think it's spelled this way.

I suppose you could manually set them but I wouldn't advise it.
The RIGHT way to set them is to call gfx_mode() or vesa_mode().
Any thing that uses any of these 3 vars should NOT be done
until a grphics mode is set. That's pretty much any manipulation
of graphics:  clearing the screen, making a virtual screen,
blitting images, loading bitmaps, probably even drawing lines.

hope this helps,
Lewis Townsend
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