Message-ID:	<370158F4.503D685B@indigo.ie>
From:	"B O'Donnell" <odonnllb AT indigo DOT ie>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Help with Libgrx contexts
Lines:	27
Date:	Wed, 31 Mar 1999 00:06:28 +0100
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X-Trace:	news.indigo.ie 922835367 194.125.205.135 (Wed, 31 Mar 1999 00:09:27 BST)
NNTP-Posting-Date:	Wed, 31 Mar 1999 00:09:27 BST
Organization:	Indigo
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

I am trying to use a context to blit my own picture onto the screen, but
doing something wrong.
I strongly suspect it's in GrCreateContext, because I can do screen to
screen blits,
but if I write

GrContext *copyfrom, *copyto;
	copyfrom=GrCreateContext(width, height, my_address, NULL);

where my_address has already been poked and pummelled without noticeable
damage, then do

	GrBitBlt(copyto, x1, y1, copyfrom, x, y, x+width-1, y+height-1,
GrWRITE);

(having printed out the numbers to make sure they're right) I get an
immediate segfault, even though the blit size is only 56*8 pixels.

If I try

	copyfrom=GrCreateContext(width, height, NULL, NULL);
	memcpy(copyfrom->gc_baseaddr, my_address, width*height);

I get no errors - and no result. Advice would be appreciated.
Regards
Brian O'Donnell
odonnllb AT indigo DOT ie

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