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From: forgeas@swinjm.UUCP (Jean-Michel Forgeas)
Newsgroups: comp.sys.amiga.tech,comp.sys.amiga.graphics,comp.sys.amiga.programmer
Subject: Re: Question re. double buffering / Intuition
Message-ID: <18fe912f.ARN0ce8@swinjm.UUCP>
Date: 16 Apr 91 10:21:35 GMT
References: <115475@unix.cis.pitt.edu>
Reply-To: forgeas@swinjm.UUCP (Jean-Michel Forgeas)
Followup-To: comp.sys.amiga.tech,comp.sys.amiga.graphics,comp.sys.amiga.programmer
Organization: The Software Winery
Lines: 55

In article <115475@unix.cis.pitt.edu>, Kenneth D Jordan writes:

> My problem arises when calling other functions such as OpenRequester,
> [..] When opening requesters
> the border often ends up on the correct RastPort but the gadgets never appear.
> Letting rp be a pointer to the rendering RastPort (which works for functions
> which require a ptr to a RastPort) and win be a pointer to the window, I've
> tried things like win->RPort = rp and win->BorderRPort = rp before opening a
> requester, but there's no apparent effect.

RastPorts are not the thing, just the bitplanes of the display.
You need only to swap pointers to the new set of bitplanes into
the window/screen bitmap, and call MakeVPort() and MrgCop().
Or you can directly swap the copper lists if you want.

If you don't want Intuition to draw into your imagery, lock one
or all the layers which are into the screen. Intuition will not
even move prop gadgets while swaping, and will do it nicely after.

Call all your rendering routines inside the 'swap' routine.
For example to open a requester:

    Swap( myOpenRequest );

and here is the myOpenRequest() function:

myOpenRequest()
{
    if (Request( Req, WorkWindow ))
        WaitIDCMP( WorkWindow, REQSET );
}

Swap( func )
VOID (*func)();
{
    LockLayer();      // lock the display
    BltBitMap();      // copy the display to hidden bitmap
    WorkWindow->RPort->BitMap = bm;            // swap the bitplanes
    sc->BitMap.Planes[...] = bm->Planes[...];
    if (func) (*func)();   // your rendering to hidden bitmap
    MakeVPort();           // the hidden becomes the display
    MrgCop();
    UnlockLayer();         // unlock the display
}

That's just the beginning, you have work to do!
And think about the fact that the modification of these pointers
is perhaps not supported under 2.0 or 5.0...
Perhaps Peter Cherna have a better solution ?
--
                                     \___/
Jean-Michel Forgeas                   \-/
cbmvax!cbmehq!cbmfra!swinjm!forgeas    |    The Software Winery
                                      -^-
                           And, where is the universe ?