First off, where did you get SDL 1.3 Pascal headers from? (Do you have
them? The old 1.2 versions won’t work, since the SDL_Surface struct has been
altered.) I’ve been working on extending the JEDI-SDL headers for 1.3. (I
assume that’s what you’re using.) Send me a
private email if you’d like a copy of my work.
we have our own bindings made from scratch – by far not complete – but
enough for our application
they are open source from the Hedgewars videogame: visit
www.hedgewars.orgto download the source
(I did not write them so if you use them just credit the author reported in
Your bug is very strange. There’s no reason that SDL_UpperBlit should
change the value of your surface pointer. That shouldn’t be possible if
your header’s set up right. Is it declared as a var parameter in the
function header? (It shouldn’t be.)
I agree that’s strange! actually tmpsurf is declared in the var section
because we need to assign an image source to it
procedure ColorizeLand(Surface: PSDL_Surface);
var tmpsurf: PSDL_Surface;
r, rr: TSDL_Rect;
x, yd, yu: LongInt;
with this you have all the function
Is the function really changing the value to nil? Have you checked that out
in a debugger? Have you checked the return value of the blit function?
It’s more likely that you’re trying to dereference the .w location and
finding something at that memory address that you shouldn’t, because the
structure of SDL_Surface has been changed.
Yes i check this myself with gdb, after stepping out of SDL_UpperBlit it
reports TMPSURF = 0x0 and so when trying to access tmpsurf^.w it crashes
what is really strange is that this very function works flawless in sdl-1.2
why were you saying that tmpsurf should be const?
From: Vittorio G. <vitto.giova at yahoo.it>
Subject: [SDL] SDL_UpperBlit returns a NULL pointer
i’m experimenting SDL 1.3 with the iPhone and i found out this bug
after a texture is applied to the surface, the source surface is trashed
and when returning to the calling function it won’t be accessible anymore.
the code follows (it’s in pascal, but it’s simple)
tmpsurf:= LoadImage(Pathz[ptCurrTheme] + ‘/LandTex’, false, true, false);
while r.y < LAND_HEIGHT do
while r.x < LAND_WIDTH do
SDL_UpperBlit(tmpsurf, nil, Surface, @r);
the program terminates when trying to access tmpsurf^.w with a
the weird thing is that this very same function works with no problem when
compiled with SDL1.2 (any platform)
any pointers i could follow?
thanks for any advice
- “I’m willing to admit that I may not always be right, but I am never