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From: zhou@brazil.psych.purdue.edu (Albert Zhou)
Newsgroups: comp.lang.pascal
Subject: Re: (R)Re: Graphic-screen to disk
Message-ID: <11529@j.cc.purdue.edu>
Date: 21 Nov 90 05:08:41 GMT
References: <25074@adm.brl.mil>
Sender: news@j.cc.purdue.edu
Reply-To: zhou@brazil.psych.purdue.edu (Albert Zhou)
Organization: Purdue University
Lines: 87

In article <25074@adm.brl.mil> CDCKAB%EMUVM1.BITNET@cunyvm.cuny.edu ( Karl Brendel) writes:
>
>In article <11518@j.cc.purdue.edu>, Albert Zhou
>  <zhou@brazil.psych.purdue.edu> writes:
>
>[deleted]
>>Actually neither is wrong. Please run the following program. I am
>>suprised to see that both addresses store the same image on my CGA.
>>Please let me know if it works the same on your machine.
>>
>>
>>uses graph;
>>type
>>    buftype1 = array[1..8000] of byte;
>>    buftype2 = array[1..16000] of byte;
>[deleted]
>>     MyBuffer1 := x1;
>>     MyBuffer2 :=x2;
>[deleted]
>>     AnotherBuffer := y;
>[deleted]
>
>I'm inclined to believe that either you don't have a "true" CGA, or your
>monitor doesn't display the image clearly, or you are being deceived by
                                                       ^^^^^^^^^^^^^^^^^
>the simplicity of your displayed pattern. When I run your progra
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>(which, admittedly, I am doing on a VGA, using the CGA driver), it i
>apparent that not all of the image is restored at the assignments to
>MyBuffer1 & MyBuffer2, but it is at the assignment to AnotherBuffer.


Now I've inserted a more complex pattern instead of the straight into the
same program. It still worked the same way as I described before. Here is
the program:


uses graph;
type
    buftype1 = array[1..8000] of byte;
    buftype2 = array[1..16000] of byte;
Procedure Draw;
var
   r : integer;
begin
     for r := 1 to 50 do
         begin
              Circle(320, 100, r*5);
         end;
end;

var
   grmode, grdriver : integer;
   MyBuffer1 : buftype1 ABSOLUTE $BA00:0;
   MyBuffer2 : buftype1 ABSOLUTE $BC00:0;
   AnotherBuffer :  buftype2 ABSOLUTE $B800:0;
   x1, x2 : buftype1;
   y : buftype2;
   n : integer;

begin
     grdriver := detect;
     initgraph(grdriver, grmode,'');
     draw;
     outtextxy(100,100, 'This is $BA00');
     x1 := MyBuffer1;
     x2 := MyBuffer2;
     readln;
     cleardevice;
     readln;
     MyBuffer1 := x1;
     MyBuffer2 :=x2;
     readln;

     cleardevice;
     readln;
     draw;
     outtextxy(100,100, 'This is $B800');
     y := AnotherBuffer;
     readln;
     cleardevice;
     readln;
     AnotherBuffer := y;
     readln;


end.