Tricks of the Mac Game Programming Gurus/TricksOfTheMacGameProgrammingGurus.iso/Information/CSMP Digest/volume 1/csmp-v1-160.txt

Text File | 1994-12-08 | 44.8 KB | 1,233 lines | [TEXT/R*ch]

C.S.M.P. Digest             Tue, 04 Aug 92       Volume 1 : Issue 160

Today's Topics:

    Walking the catalog b-tree...
    Drawing with the mouse
    Converting floats to strings Question
    SOUND: Volume decreases after first command
    Programmers Switch/Handles
    Calling Apple Events from an Init/CDEV?



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-------------------------------------------------------

From: [e-mail] (Cameron Esfahani)
Subject: Walking the catalog b-tree...
Date: 13 Jun 92 03:21:35 GMT
Organization: caen

Pity me...I have figured that the only way that I can find a file if
I just have it's file reference number and volume reference number
is to open the catalog tree file on the volume and search through it.
Now, IM-IV is very, very bad in explaining simple things such as the
size of the nodes in the catalog b-tree.  Does anyone out there have
any information, code, suggestions on how to do this?  I have
written a simple app which opens the catalog tree file up, but I don't
see any recognizable information until about 500 bytes into the buffer...
Does anyone know anything about this?


Thanks,

Cameron Esfahani
[e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 15 Jun 92 20:10:08 GMT
Organization: Taligent

In article <mN--2z=@engin.umich.edu>, [e-mail] (Cameron Esfahani)
writes:
>
> Pity me...I have figured that the only way that I can find a file if
> I just have it's file reference number and volume reference number
> is to open the catalog tree file on the volume and search through it.
> Now, IM-IV is very, very bad in explaining simple things such as the
> size of the nodes in the catalog b-tree.  Does anyone out there have
> any information, code, suggestions on how to do this?  I have
> written a simple app which opens the catalog tree file up, but I don't
> see any recognizable information until about 500 bytes into the buffer...
> Does anyone know anything about this?

You shouldn't have to open up the catalog file yourself. Either use PBCatSearch
(under 7.0) or use the routine shown in Mac Technote #68.

So why is it that you only have the file's ID number and vRefNum? Why don't you
have it's dirID?

- --
Keith Rollin
Phantom Programmer
Taligent, Inc.


+++++++++++++++++++++++++++

From: Cameron Esfahani <[e-mail]>
Date: Mon, 15 Jun 92 23:30:10 EDT
Organization: caen

>You shouldn't have to open up the catalog file yourself. Either use
PBCatSearch
>(under 7.0) or use the routine shown in Mac Technote #68.
>
>So why is it that you only have the file's ID number and vRefNum? Why
don't you
>have it's dirID?
>
>--
>Keith Rollin
>Phantom Programmer
>Taligent, Inc.

I have figured out how to find out what is currently selected in the
Finder.  However, at the place I do my "thing", I only have the file
reference number, volume reference number, name, type and creator
available to me.  I have found a solution to my problem however, I just
use PBCatSearch to search on name, type, and creator on the volume.
I then ues PBGetCatInfo to compare all the file reference numbers.
Cameron "Make Mine a 99" Esfahani
[e-mail]

+++++++++++++++++++++++++++

From: Cameron Esfahani <[e-mail]>
Date: Mon, 15 Jun 92 23:31:15 EDT
Organization: caen

>You shouldn't have to open up the catalog file yourself. Either use
PBCatSearch
>(under 7.0) or use the routine shown in Mac Technote #68.
>
>So why is it that you only have the file's ID number and vRefNum? Why
don't you
>have it's dirID?
>
>--
>Keith Rollin
>Phantom Programmer
>Taligent, Inc.

I have figured out how to find out what is currently selected in the
Finder.  However, at the place I do my "thing", I only have the file
reference number, volume reference number, name, type and creator
available to me.  I have found a solution to my problem however, I just
use PBCatSearch to search on name, type, and creator on the volume.
I then ues PBGetCatInfo to compare all the file reference numbers.
Cameron "Make Mine a 99" Esfahani
[e-mail]

+++++++++++++++++++++++++++

From: David R. Falkenburg <[e-mail]>
Date: Tue, 16 Jun 92 11:19:10 EDT
Organization: University of Michigan College of Engineering

>In article <mN--2z=@engin.umich.edu>, [e-mail] (Cameron
Esfahani)
>writes:
>>
>> Pity me...I have figured that the only way that I can find a file if
>> I just have it's file reference number and volume reference number
>> is to open the catalog tree file on the volume and search through it.
>> Now, IM-IV is very, very bad in explaining simple things such as the
>> size of the nodes in the catalog b-tree.  Does anyone out there have
>> any information, code, suggestions on how to do this?  I have
>> written a simple app which opens the catalog tree file up, but I don't
>> see any recognizable information until about 500 bytes into the
buffer...
>> Does anyone know anything about this?

You DON'T want to walk th B-Trees yourself.  Trust me.

If you've got a "file number", why not try _GetFCBInfo...  See IM-IV-179.

This better be a good hack

- -dave falkenburg
 university of michigan, college of engineering

- --dave falkenburg
- --university of michigan college of engineering
- [e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Elizabeth Wylie)
Date: 17 Jun 1992 00:51:27 GMT
Organization: U. C. Berkeley Open Computing Facility

The problem with GetFCBInfo is that it will only find the file if it is open. A
n undocumented feature of PBGetCatInfo allows you to pass a file number in the
ioDirID field.  Since this is undocumented, it could fail in the future, but
because of the way the disk catalog is set up, I'd be surprised if it did.

If you are talking about file reference unmbres, then GetFCBInfo is the way to
go.

(Why do you only have the file number?!)

- -E. Wylie


+++++++++++++++++++++++++++

From: [e-mail] (John Wallace)
Date: 25 Jun 92 18:18:19 GMT
Organization: TRW Data Systems Center, Redondo Beach, CA

In article <[e-mail]> [e-mail] (Elizabeth Wylie) writes:
>An undocumented feature of PBGetCatInfo allows you to pass a file number in the
>ioDirID field.  Since this is undocumented, it could fail in the future, but
>because of the way the disk catalog is set up, I'd be surprised if it did.
>
>-E. Wylie
>

InsideMac-IV claims that if you pass in a dirId in ioDirId and a -1
in ioDirIndex that it will return information about a directory.  I've
tried the same thing with passing a fileId in the ioDirId field, and
it failed.  My understanding is that it isn't possible for the B-tree
to provide access using fileIds because of the way it stores the data.
Am I (hopefully) wrong?

Thanks!
John

+++++++++++++++++++++++++++

From: [e-mail] (Ben Hekster)
Organization: University of Twente, Dept. of Computer Science
Date: Fri, 26 Jun 1992 03:33:15 GMT

In article <[e-mail]> [e-mail] (Elizabeth Wylie) writes:
>An undocumented feature of PBGetCatInfo allows you to pass a file number in the
>ioDirID field.  Since this is undocumented, it could fail in the future, but
>because of the way the disk catalog is set up, I'd be surprised if it did.
>
>-E. Wylie

In article <[e-mail]> [e-mail] (John Wallace) writes:
>
>InsideMac-IV claims that if you pass in a dirId in ioDirId and a -1
>in ioDirIndex that it will return information about a directory.  I've
>tried the same thing with passing a fileId in the ioDirId field, and
>it failed.  My understanding is that it isn't possible for the B-tree
>to provide access using fileIds because of the way it stores the data.
>Am I (hopefully) wrong?

I hope you are (and I am, too).  I tried it and it didn't work for me,
either.  It's unfortunate, because it would have been much nicer to use
PBGetCatInfo for files and directories alike, instead of PBResolveFileID
for files.

    However, PBGetCatInfo *will* return both file and directory
IDs in ioDirID.

Ah, well.

- --
Ben `Hackster' Hekster        | "He bides his time and thinks,
[e-mail]        |  'There must be more to life than this!'"

+++++++++++++++++++++++++++

From: [e-mail] (Tim Dierks, software saboteur)
Date: 1 Jul 92 17:49:45 GMT
Organization: MacDTS Misfits

In article <[e-mail]>, [e-mail] (John Wallace) writes:
>
> In article <[e-mail]> [e-mail] (Elizabeth Wylie) writes:
> >An undocumented feature of PBGetCatInfo allows you to pass a file number in the
> >ioDirID field.  Since this is undocumented, it could fail in the future, but
> >because of the way the disk catalog is set up, I'd be surprised if it did.
> >
> >-E. Wylie
> >
>
> InsideMac-IV claims that if you pass in a dirId in ioDirId and a -1
> in ioDirIndex that it will return information about a directory.  I've
> tried the same thing with passing a fileId in the ioDirId field, and
> it failed.  My understanding is that it isn't possible for the B-tree
> to provide access using fileIds because of the way it stores the data.
> Am I (hopefully) wrong?
>
> Thanks!
> John

Just call PBResolveFileIDRef(), as documented on page 25-46 of IM VI.  It
will take a file ID and locate the appropriate file.

Tim Dierks
MacDTS, but I speak for the trees


+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 1 Jul 92 19:57:38 GMT
Organization: Taligent

In article <[e-mail]>, [e-mail] (Tim Dierks,
software saboteur) writes:
>
> In article <[e-mail]>, [e-mail] (John
Wallace) writes:
> >
> > In article <[e-mail]> [e-mail]
(Elizabeth Wylie) writes:
> > >An undocumented feature of PBGetCatInfo allows you to pass a file number in
the
> > >ioDirID field.  Since this is undocumented, it could fail in the future,
but
> > >because of the way the disk catalog is set up, I'd be surprised if it did.
> > >
> > >-E. Wylie
> > >
> >
> > InsideMac-IV claims that if you pass in a dirId in ioDirId and a -1
> > in ioDirIndex that it will return information about a directory.  I've
> > tried the same thing with passing a fileId in the ioDirId field, and
> > it failed.  My understanding is that it isn't possible for the B-tree
> > to provide access using fileIds because of the way it stores the data.
> > Am I (hopefully) wrong?
> >
> > Thanks!
> > John
>
> Just call PBResolveFileIDRef(), as documented on page 25-46 of IM VI.  It
> will take a file ID and locate the appropriate file.
>

My System 7.0 File Manager knowledge is a little rusty, but I think
PBResolveFileIDRef works only if a file thread record has been created by first
calling PBCreateFileIDRef (see the last line of the PBResolveFileIDRef
description). I've never actually made these calls, so if you have experience
bearing out your comment, I'll defer to you.

- --
Keith Rollin
Phantom Programmer
Taligent, Inc.


---------------------------

From: [e-mail] (Alex Poon)
Subject: Drawing with the mouse
Organization: Xerox PARC
Date: 22 Jun 92 20:56:08 GMT

I have an external window in hypercard in which I want to allow users
to draw with a mouse.  The code segment is as follows:

...
switch (event.what) {

  case mouseDown:
     GetMouse(&curpoint);
     MoveTo(curpoint.h,curpoint.v);
     while (StillDown()) {
        GetMouse(&curpoint);
        LineTo(curpoint.h,curpoint.v);
        }
     break;

...
(where GetMouse(), StillDown(), MoveTo(), and LineTo() are toolbox
 routines).

The problem is that the drawing turns out not to be smooth -- if I try
drawing large circles really fast, I get triangles, squares, and other
various polygons.  Drawing with the hypercard pencil tool is smoother,
but I do not want to use the built-in pencil tool because I need to
do some processing while the user draws in real-time.

Does anyone know of a solution?  In general, what is the best way to
draw with the mouse?

Alex Poon
[e-mail]



+++++++++++++++++++++++++++

From: [e-mail] (Dave Leonard)
Date: 23 Jun 92 10:05:32 GMT
Organization: Department of Mathematics, Uni of Newcastle, Oz.

[e-mail] (Alex Poon) writes:

>I have an external window in hypercard in which I want to allow users
>to draw with a mouse.  The code segment is as follows:

>The problem is that the drawing turns out not to be smooth -- if I try
>drawing large circles really fast, I get triangles, squares, and other
>various polygons.  Drawing with the hypercard pencil tool is smoother,
>but I do not want to use the built-in pencil tool because I need to
>do some processing while the user draws in real-time.

the problem appears to be the time for each cycle of your while loop

well it seems pretty compact, maybe your compiler doesnt optimize too well
and your code spends a bit of time in glue routines?

Maybe you could hand-assemble it using inline assembly: asm { }

Not being an absolute wizz at this, i couldnt tell you what to put between
the { and } but your code looked pretty simple and should be Very easy to
implement this way... just the while loop

anybody out there want to post the asm {} bit?

dave

- --
Dave Leonard, Uni of Newcastle           [e-mail]
    "l;ksd8721" - cat on a keyboard

+++++++++++++++++++++++++++

From: [e-mail] (Jon W{tte)
Organization: Royal Institute of Technology, Stockholm, Sweden
Date: Mon, 29 Jun 1992 10:44:23 GMT

> [e-mail] (Dave Leonard) writes:

   >I have an external window in hypercard in which I want to allow users
   >to draw with a mouse.  The code segment is as follows:

    while ( StillDown ( ) ) {

        GetMouse ( & pt ) ;
        LineTo ( pt . h , pt . v ) ;
    }

   >The problem is that the drawing turns out not to be smooth -- if I try
   >drawing large circles really fast, I get triangles, squares, and other

   the problem appears to be the time for each cycle of your while loop

   well it seems pretty compact, maybe your compiler doesnt optimize too well
   and your code spends a bit of time in glue routines?

   Maybe you could hand-assemble it using inline assembly: asm { }


This is a common misconception. Trust me, the 10 or 20 instructions
emitted by the compiler for the loop mechanics is NOTHING compared
to the time that's spent inside the toolbox for the traps. If the
loop looks as shown above, there isn't much more you can do unless
you draw directly to screen (check the UMPG for such code, and a
decent graphics book for how to draw fast lines) and even that won't
give you toomuch of a speedup.

However, the loop as it stands should be fast enough, I strongly
believe something else is going on as well as the drawing. If you
still can't make it work, you can't; buy a faster machine.

- --
         Jon W{tte, Svartmangatan 18, S-111 29 Stockholm, Sweden

 "Difficult, obscure, incoherent and nonstandard does not imply more power."
               - Andrew Kass in comp.sys.mac.hardware

+++++++++++++++++++++++++++

From: [e-mail] (Reid Ellis)
Organization: Alias Research, Inc., Toronto ON Canada
Date: Tue, 30 Jun 1992 03:48:29 GMT

Dave Leonard <[e-mail]> writes:
|I have an external window in hypercard in which I want to allow users
|to draw with a mouse.  The code segment is as follows:
|
|    while (StillDown()) {
|        GetMouse(& pt);
|        LineTo(pt . h , pt . v);
|    }
|
|The problem is that the drawing turns out not to be smooth -- if I try
|drawing large circles really fast, I get triangles, squares, ...

Someone else <???> writes:
|   Maybe you could hand-assemble it using inline assembly: asm { }

Jon W{tte <[e-mail]> writes:
|This is a common misconception. Trust me, the 10 or 20 instructions
|emitted by the compiler for the loop mechanics is NOTHING compared
|to the time that's spent inside the toolbox for the traps.

Would the code benefit from GetTrapAddress() to avoid the toolbox trap
mechanism?  Or does this have the unfortunate side effect of possibly
deaccellerating and Quickdraw accellerators running?

Reid
- --
Reid Ellis
[e-mail]        ||           [e-mail]
[e-mail] ||  [phone] [work]

+++++++++++++++++++++++++++

From: [e-mail] (Charles Jacobs)
Organization: Computer Science & Engineering, U. of Washington, Seattle
Date: Tue, 30 Jun 92 07:53:14 GMT

Dave Leonard <[e-mail]> writes:
|I have an external window in hypercard in which I want to allow users
|to draw with a mouse.  The code segment is as follows:
|
|    while (StillDown()) {
|        GetMouse(& pt);
|        LineTo(pt . h , pt . v);
|    }
|
|The problem is that the drawing turns out not to be smooth -- if I try
|drawing large circles really fast, I get triangles, squares, ...

  Yeah, I did the same thing a couple of weeks ago, and what helped me a lot
was to remember the old location and only draw if it's necessary -- made a
dramatic improvement, without resorting to yuckiness like assembly or
other stuff I don't understand (heh)..
try this (forgive me for the syntactic & stylistic errors that are bound
to follow... I'm tired):
    GetMouse (& oldPt);
    while (StillDown()) {
        GetMouse(& pt);
        if (oldPt != pt) {
            LineTo (pt.h, pt.v);
            oldPt = pt
        }
    }

I think that's right... anyway, you get the idea...
chuck



+++++++++++++++++++++++++++

From: [e-mail] (Scott Bronson)
Date: 1 Jul 92 17:36:19 GMT

In <[e-mail]> [e-mail] (Jon W{tte) writes:

>> [e-mail] (Dave Leonard) writes:

>   >I have an external window in hypercard in which I want to allow users
>   >to draw with a mouse.  The code segment is as follows:

>    while ( StillDown ( ) ) {

>        GetMouse ( & pt ) ;
>        LineTo ( pt . h , pt . v ) ;
>    }

>   >The problem is that the drawing turns out not to be smooth -- if I try
>   >drawing large circles really fast, I get triangles, squares, and other


>However, the loop as it stands should be fast enough, I strongly
>believe something else is going on as well as the drawing. If you
>still can't make it work, you can't; buy a faster machine.

There is a more complex technique you can try.  I think Fractal Design's
Painter uses it.  Install a VBL task that queues mouse locations about
every other tick into a large buffer.  Then you are assured that the
mouse will be polled 30 times a second, resulting in a (hopefully)
smooth line.  You can play with the number of times a second the mouse
is polled; the larger the buffer, the more points can be stored before
the computer catches up, and the smoother the curve.

Then, your main program can simply go running through this buffer in
a tight loop:

#include<sys/stdsyntaxdisclaimer.h>

Point oldpoint, mousepoint, *mp;

while( StillDown() ) {
    mousepoint = *(mp++);
    if( ((long*)&mousepoint) != ((long*)&oldpoint) ) {
    oldpoint = mousepoint;
    LineTo( mousepoint );
    }
}

A circular buffer would allow you to track the mouse for as long as the
user holds it down.  Just make sure that your loop doesn't pass your VBL,
(concievable on moderately fast machines especially with accelerated QD)
or you'll get garbage instead of good mouse locations.

    - Scott

+++++++++++++++++++++++++++

From: [e-mail] (Matt Mora)
Date: 1 Jul 92 16:00:44 GMT
Organization: SRI International, Menlo Park, California

In article <[e-mail]> [e-mail] (Reid Ellis) writes:
>Dave Leonard <[e-mail]> writes:

>|The problem is that the drawing turns out not to be smooth -- if I try
>|drawing large circles really fast, I get triangles, squares, ...

>Would the code benefit from GetTrapAddress() to avoid the toolbox trap
>mechanism?  Or does this have the unfortunate side effect of possibly
>deaccellerating and Quickdraw accellerators running?

You could try setting the mouse tracking speed to a lower value.
This should give a more accurate tracking of the mouse. The vbl task
won't give you the huge delta changes that give you the triangles and
squares. Its probably not a nice thing to do to a user but if you set it
back to what it was before the tracking code maybe the user won't notice.

Matt











- --
___________________________________________________________
Matthew Mora                |   my Mac  [e-mail]
SRI International           |  my unix  [e-mail]
___________________________________________________________

---------------------------

From: [e-mail] (Peter G. Cramer)
Subject: Converting floats to strings Question
Date: 23 Jun 92 21:02:42 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)


Help!   I need a C function that converts a float to a string.

ANSI C provides a function called "gcvt" for this purpose
(it's part of stdlib.h), but it wasn't supplied with Think C.
If anyone can direct me to source code for this, I would
be eternally grateful!

All the Best
- --
Peter G. Cramer, Physics Department, CWRU
University Circle   Cleveland, Ohio 44106
[phone]            [e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Stephen Uitti)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Date: Wed, 24 Jun 1992 00:06:30 GMT

In article <[e-mail]> [e-mail] (Peter G. Cramer) writes:
>
>Help!   I need a C function that converts a float to a string.
>
>ANSI C provides a function called "gcvt" for this purpose
>(it's part of stdlib.h), but it wasn't supplied with Think C.
>If anyone can direct me to source code for this, I would
>be eternally grateful!

How about sprintf()?  You can use it from ANSI-small too.
It works for me.

Stephen.
[e-mail]

+++++++++++++++++++++++++++

From: [e-mail]
Date: 24 Jun 92 12:49:59 GMT
Organization: AECL RESEARCH

I also need to convert a float to a string and vice versa. On page 69 of
Inside Macintoch IV it says three new routine have been added to the
Binary-Decimal Convertion Package to do the string to SANE binary data
format conversion and SANE binary data to string conversion. It also
states these functions are documented in the "Apple Numerics Manual". My
problem is that I can not get a hold of this manual. Could some kind soul
tell me how these work or point me to some FTP'able item that would.

Thanks,

[e-mail]
Michael Dobrohoczki
Chalk River Laboratories
Atomic Energy Canada Ltd.

+++++++++++++++++++++++++++

From: [e-mail] (Tom Dowdy)
Date: 1 Jul 92 19:11:20 GMT
Organization: Apple Computer, Inc.

In article <[e-mail]>, [e-mail]
(Stephen Uitti) wrote:
> In article <[e-mail]> [e-mail] (Peter G. Cramer) writes:
> >Help!   I need a C function that converts a float to a string.
>
> How about sprintf()?  You can use it from ANSI-small too.
> It works for me.

How about using the International Utilities instead?  That way your
application will work in places other than the US.

 Tom Dowdy                 Internet:  [e-mail]
 Apple Computer MS:81KS    UUCP:      {sun,voder,amdahl,decwrl}!apple!dowdy
 20525 Mariani Ave         AppleLink: DOWDY1
 Cupertino, CA 95014
 "The 'Ooh-Ah' Bird is so called because it lays square eggs."

---------------------------

From: [e-mail] (rodney jacks)
Subject: SOUND: Volume decreases after first command
Organization: Motorola Inc, Austin, Texas
Date: Thu, 25 Jun 1992 14:49:16 GMT

Help,

I'm having a couple of problems with the Sound Manager that I just
can't figure out.  I'm attempting to play a soundtrack by issuing
a series of sound commands to the sound manager.  Before starting
the soundtrack, my application sets the sound volume to a particular
volume (that was saved in a preference file) using SetSoundVol.
When I issue the commands, the soundtrack starts to play and after
playing the first command/sound at the new volume level, the volume
switches back to the original volume level.

If I change the volume setting while the soundtrack is already playing
using the Set Volume menu I have provided in my app, everything
works ok (ie. the soundtrack plays at the new volume level).

Other than the volume level the soundtrack plays just fine.

The other problem I have is that when the soundtrack is playing
and I play some other sound effect in a different channel using
SoundPlay both the sound effect and the soundtrack seem to
decrease in volume until the sound effect is finished.

I'm basically using the DTS sample code from SoundApp.  I have
added procedures for starting and stopping the soundtrack, and setting
the volume level.  I use a VBL routine to keep the soundtrack playing.

I'm running on System 7.0.1 with Tuna Helper if that is important.

Thanks for your help,
- -Rodney

***********************************************************************
**  Rodney Jacks                                                     **
**  Motorola Inc, Austin, Texas                                      **
**  E-mail:  [e-mail]                              **
**  Picard asks Worf what he thought of commanding the _Enterprise_  **
**  "Comfortable chair."     ST.TNG _The Emissary_                   **
***********************************************************************



+++++++++++++++++++++++++++

From: [e-mail] (Paul Potts)
Organization: Instructional Technology Laboratory, University of Michigan
Date: Thu, 25 Jun 92 18:44:32 GMT

In article <[e-mail]> [e-mail] (rodney jacks) writes:
>Help,
>
<first problem left out to save space>...
>
>The other problem I have is that when the soundtrack is playing
>and I play some other sound effect in a different channel using
>SoundPlay both the sound effect and the soundtrack seem to
>decrease in volume until the sound effect is finished.
>
>I'm basically using the DTS sample code from SoundApp.  I have
>added procedures for starting and stopping the soundtrack, and setting
>the volume level.  I use a VBL routine to keep the soundtrack playing.
>
>I'm running on System 7.0.1 with Tuna Helper if that is important.

I'm uncertain about the first problem, but the second problem seems clear:
on the Mac, the volume available for playing sampled sounds gets divided up
between the various sampled sounds playing in different channels. If I play
a sample in channel one and it sounds X loud, if I open up another channel
and play another sample at the same time, the first sample will only sound
roughly X/2 loud.

I don't have a really good suggestion to get around this, other than that
you try adjusting to a different volume level when playing sounds
simultaneously. Remember, you've got both the sound chip amplitude (with
setAmpCmd) and the speaker volume to work with, so it is possible to get
fairly fine control over the sound volume levels.

- --
The essence of OOP: "With all this horse manure, I know there's got to be
                     a pony in here somewhere!"
Paul R. Potts, Software Designer --- [e-mail] <--- me!

+++++++++++++++++++++++++++

From: [e-mail] (Jim Reekes)
Date: 1 Jul 92 19:11:58 GMT
Organization: Apple Computer, Inc.

In article <[e-mail]>, [e-mail] (Paul Potts) writes:
>
> In article <[e-mail]> [e-mail] (rodney jacks) writes:
> >Help,
> >
> <first problem left out to save space>...
> >
> >The other problem I have is that when the soundtrack is playing
> >and I play some other sound effect in a different channel using
> >SoundPlay both the sound effect and the soundtrack seem to
> >decrease in volume until the sound effect is finished.
> >
> >I'm basically using the DTS sample code from SoundApp.  I have
> >added procedures for starting and stopping the soundtrack, and setting
> >the volume level.  I use a VBL routine to keep the soundtrack playing.
> >
> >I'm running on System 7.0.1 with Tuna Helper if that is important.

This is a design limitation of the Sound Manager.  I'm well aware of the
problem, and we've got a solution in the workings.  Mean while, there's not
much you can to about this.  The only suggestion I can think of it try
playing all of your channels at the same time and you'll not have the volumes
cutting in and out.  When you want one of the channels to stop playing,
change it to a really slow rate (using the rateCmd or freqCmd) that's
below the audible range.  It's a hack and it's a gross idea, but that's
the only suggestion I have.  Just remember that mixing channels costs
CPU time.

- -----------------------------------------------------------------------
Jim Reekes, Polterzeitgeist  |     Macintosh Toolbox Engineering
                             |          Sound Manager Expert
Apple Computer, Inc.         | RAll opinions expressed are mine, and do
20525 Mariani Ave. MS: 81-KS |   not necessarily represent those of my
Cupertino, CA 95014          |       employer, Apple Computer Inc.S



---------------------------

From: bberqu@sagpd1 ()
Subject: Programmers Switch/Handles
Date: Mon, 29 Jun 1992 20:28:48 GMT


I'm new to the mac so bear with me:

This is probably a really stupid question, but I can't seem to find it in
the manual, how do you reset and interrupt the mac on an LC II, I was
reading in my Macsbug manual that the functionality for the programmers
switch is built into the keyboard (what is the key combination or whatever)?

This one's for programmers, when creating a window can I use a Handle for
the wStorage parameter in the call to GetNewWindow, if I use a pointer
everything works fine, but if I create it with a Handle, this causes me
problems later on in the program for instance in another subroutine after
the window is created I make a call to sprintf to format some data (this
causes the mac to lockup), I'm not doing anything (that I know of) to
the memory obtained by the handle when I make the call to sprintf,
this works just fine by using pointers instead of handles.  Is it OK
to use relocatable blocks for window records?

This is how I call GetNewWindow with a handle:

       wptr = GetNewWindow ( WINDOWID, *handle, .....

You can email your responses.

Thanks Brian

P.S. I hope I don't get alot of rtfm's, because I have been.

+++++++++++++++++++++++++++

From: [e-mail] (timothy dwight fullerton)
Organization: The Ohio State University, Department of Computer and Information Science
Date: Tue, 30 Jun 1992 01:35:18 GMT


    Brian,

    Under system 7, you can interrupt with [cmd]-[option]-[esc].

    I am running system 6 on an LC I, and my reboot is [cmd]-[ctrl]-
[power on]. There also exists a programmers switch init which I use (just
in case you prefer system 6 also) that is shareware. I am not at home, and
I cannot remember off the top of my head the author and version, but you
should be able to get it from FTP sites or compuserve. If not, and you need
it, send me mail.

    By the way, it was six months before I learned this info. It would
be nice if Apple would put it in our LC manuals, wouldn't it?

        good luck,
            Tim Fullerton

        [e-mail]

        [e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Betty Lee)
Organization: Stanford University -- Electrical Engineering
Date: Tue, 30 Jun 1992 03:20:27 GMT

[e-mail] (timothy dwight fullerton) writes:

+     Under system 7, you can interrupt with [cmd]-[option]-[esc].

Uh, that's not an interrupt.  That's a force-quit to the application.
If you have MacsBug, interrupt should be <cmd>-<power> on the new Macs.
(Sorry, I can't find the original article, so I'm just responding to this
one.)  It worked for me in both System 6 AND System 7, so I think it's a
hardware feature.

+     I am running system 6 on an LC I, and my reboot is [cmd]-[ctrl]-
+ [power on]. There also exists a programmers switch init which I use (just
+ in case you prefer system 6 also) that is shareware. I am not at home, and
+ I cannot remember off the top of my head the author and version, but you
+ should be able to get it from FTP sites or compuserve. If not, and you need
+ it, send me mail.

It's on sumex-aim.Stanford.EDU under /info-mac/ex/programmers-key-142.hqx.
>From the doc...
Programmer's Key was written by:
Paul Mercer
AppleLink: MERCER1
Internet: [e-mail]
P.O. Box 160165
Cupertino, CA  95014-0165

+     By the way, it was six months before I learned this info. It would
+ be nice if Apple would put it in our LC manuals, wouldn't it?

Aw...  But that would take all the fun out of learning all these neat
tricks by yourself!  It's little things like that which separate the REAL
computer enthusiasts from the theorists who can get a BS in CS and know
nothing practical whatsoever.  I know FOOD RESEARCH majors who can put any
computer to better use than some CS grads.  (Then again, I might be feeling
inferior because I have no interest in matrices, encryption techniques,
inductive proofs, and prime number generating algorithms...  NOT!)

- --
         Betty Lee          | The main difference between a User and a Hacker:
      P. O. Box 5748        |    A User buys a faster computer to spend
    Stanford, CA 94309      |    _less_ time with it.  Happy hacking!
[e-mail] |                          -- From rec.humor.funny

+++++++++++++++++++++++++++

From: [e-mail] (Charles B. Cranston)
Organization: UM Home for the Terminally Analytical
Date: Tue, 30 Jun 1992 18:35:18 GMT

Nobody answered his other question, and I don't think I can get email
back to an address like  bberqu@sagpd1  (:-o) so:

In article <1992Jun29.202848.11057@sagpd1>, bberqu@sagpd1 () writes:

> This one's for programmers, when creating a window can I use a Handle for
> the wStorage parameter in the call to GetNewWindow, if I use a pointer
> everything works fine, but if I create it with a Handle, this causes me
> problems later on in the program...

You can't put a GrafPort or anything containing a GrafPort in a handle
because the data in handles can move around and the Macintosh just can't
handle GrafPorts moving around.  Note that there is a GrafPort in a
Window and there is a Window in a Dialog so you cannot put any of these
things into a handle.

Exception: you could leave the handle locked during the whole time these
things are being used, then pass a pointer (the CONTENTS of the handle)
to the routines which usually take a pointer to storage.  This might be
useful if you have a huge number of windows of which only some are actually
being used at any one time, and any one window is only used for a short
time so the locking of the handles wouldn't cause long-term fragmentation.
Note that just hiding the window will not do, you would have to get it
out of the window chain entirely before you could allow the handle to
become unlocked.  This means you would have to destroy the window...

What I tend to do is allocate a static global array of Dialogs and have
init code chain them together into a free list, then allocate and
deallocate from this free list.  The only problem is that the maximum
number of Dialogs is fixed at compile time.  One could compute at init
time the maximum number of windows and allocate a nonrelocatable block
containing all the window space and allocate it the same way.  I don't
think this would be much different, however, from just letting the
system allocate and free the blocks by passing nil for wStorage.



+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 30 Jun 92 18:30:59 GMT
Organization: Taligent

In article <1992Jun29.202848.11057@sagpd1>, bberqu@sagpd1 writes:
>
> This one's for programmers, when creating a window can I use a Handle for
> the wStorage parameter in the call to GetNewWindow, if I use a pointer
> everything works fine, but if I create it with a Handle, this causes me
> problems later on in the program for instance in another subroutine after
> the window is created I make a call to sprintf to format some data (this
> causes the mac to lockup), I'm not doing anything (that I know of) to
> the memory obtained by the handle when I make the call to sprintf,
> this works just fine by using pointers instead of handles.  Is it OK
> to use relocatable blocks for window records?
>
> This is how I call GetNewWindow with a handle:
>
>        wptr = GetNewWindow ( WINDOWID, *handle, .....

Technote #155 talks about this. Essentially, it says don't do it.

- --
Keith Rollin
Phantom Programmer
Taligent, Inc.


+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 1 Jul 92 17:24:01 GMT
Organization: Taligent

In article <[e-mail]>, [e-mail] (Charles B.
Cranston) writes:
>
> Nobody answered his other question, and I don't think I can get email
> back to an address like  bberqu@sagpd1  (:-o) so:
>
> In article <1992Jun29.202848.11057@sagpd1>, bberqu@sagpd1 () writes:
>
> > This one's for programmers, when creating a window can I use a Handle for
> > the wStorage parameter in the call to GetNewWindow, if I use a pointer
> > everything works fine, but if I create it with a Handle, this causes me
> > problems later on in the program...
>
> You can't put a GrafPort or anything containing a GrafPort in a handle
> because the data in handles can move around and the Macintosh just can't
> handle GrafPorts moving around.  Note that there is a GrafPort in a
> Window and there is a Window in a Dialog so you cannot put any of these
> things into a handle.
>
> Exception: you could leave the handle locked during the whole time these
> things are being used, then pass a pointer (the CONTENTS of the handle)
> to the routines which usually take a pointer to storage.  This might be
> useful if you have a huge number of windows of which only some are actually
> being used at any one time, and any one window is only used for a short
> time so the locking of the handles wouldn't cause long-term fragmentation.
> Note that just hiding the window will not do, you would have to get it
> out of the window chain entirely before you could allow the handle to
> become unlocked.  This means you would have to destroy the window...

I just wanted to clarify what Ben means by leaving "the handle locked during the
whole time these things are being used." Be sure that the handle is locked
during the ENTIRE EXISTANCE of the window. That is, it is _not_ OK to do
something like:

    HLock((Handle) myWindowHandle);
    SetPort(*myWindowHandle);
    UpdateMyWindow(myWindowHandle);
    SetPort(mySafeDummyPort);
    HUnlock((Handle) myWindowHandle);

After the grafPort within the window record is created, it MUST NOT MOVE! See
Technote #155 for an explanation.

Since the window record must be locked during its entire existance, you might
was well create it as a non-relocatable block in the first place.

- --
Keith Rollin
Phantom Programmer
Taligent, Inc.


---------------------------

From: [e-mail] (Andrew E Page)
Subject: Calling Apple Events from an Init/CDEV?
Organization: The World Public Access UNIX, Brookline, MA
Date: Tue, 30 Jun 1992 12:15:47 GMT


    Is it possible to call Apple Events from an INIT/CDEV?  I'm working
on something that might otherwise require a DRVR, but I think that
Apple Events might be friendlier to some components of the project.

DoD# 0581   1990 Suzuki VX800   MSF Intro Class Aug 1990
- --
Andrew E. Page CTO(Warrior Poet)|   Decision and Effort The Archer and Arrow
DSP Ironworks                   |     The difference between what we are
Macintosh and DSP Technology    |           and what we want to be.

+++++++++++++++++++++++++++

From: [e-mail] (Grobbins)
Date: 30 Jun 92 18:12:57 GMT
Organization: Guillermo's Group

In article <[e-mail]> [e-mail] (Andrew E Page) writes:
>    Is it possible to call Apple Events from an INIT/CDEV?

It's not a good idea, but you can use the PPC Toolbox to have your
INIT communicate with a background application which serves as the
host and target for the Apple events.  For an example, see the
sample aecdev-aedaemon.hqx in the directory

  dts/mac/sc/snippets/toolbox.iac/apple.events

on ftp.apple.com


Grobbins               [e-mail]

Usual disclaimers apply


+++++++++++++++++++++++++++

From: [e-mail] (Greg L. Anderson)
Date: 30 Jun 92 19:07:34 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Andrew E Page) writes:
>    Is it possible to call Apple Events from an INIT/CDEV?

You may AESend from a CDEV/CODE resource.  If you never call WaitNextEvent/
GetNextEvent, you won't be able to receive a reply, though.

- --
=====================   ===========================   =====================
Greg Anderson           Apple Computer, Inc.            O    Ponnuki    O
Macintosh Bodhisattva   Macintosh System Software      O O  is  ideal  O O
[e-mail]       Finder Team                     O     shape     O
=====================   ===========================   =====================

+++++++++++++++++++++++++++

From: [e-mail] (Lawrence D'Oliveiro, Waikato University)
Date: 2 Jul 92 03:31:42 GMT
Organization: University of Waikato, Hamilton, New Zealand

In article <[e-mail]>, [e-mail] (Greg L. Anderson) writes:
> In article <[e-mail]> [e-mail] (Andrew E Page) writes:
>>    Is it possible to call Apple Events from an INIT/CDEV?
>
> You may AESend from a CDEV/CODE resource.

Just to amplify on this, you may call AESend from a cdev resource, *only*
because you're running in the Finder's context, and the Finder is high-level-
event aware. AESend doesn't work from the context of an application that isn't
high-level-event aware.

Lawrence
been there, done that

+++++++++++++++++++++++++++

From: [e-mail] (Jeremy Roussak)
Date: 1 Jul 92 20:43:24 GMT
Organization: Computer Science Dept, QMW, University of London

In <[e-mail]> [e-mail] (Grobbins) writes:

>>    Is it possible to call Apple Events from an INIT/CDEV?

>It's not a good idea, but you can use the PPC Toolbox to have your
>INIT communicate with a background application which serves as the
>host and target for the Apple events.

Why is this not a good idea? It seems to be the only way in
which this most useful task can be accomplished.

Jeremy

+++++++++++++++++++++++++++

From: [e-mail] (Grobbins)
Date: 2 Jul 92 09:29:51 GMT
Organization: Apple CTS

In article <[e-mail]> [e-mail] (Jeremy Roussak) writes:
>In <[e-mail]> [e-mail] (Grobbins) writes:
>>>    Is it possible to call Apple Events from an INIT/CDEV?
>>It's not a good idea, but you can use the PPC Toolbox to have your
>>INIT communicate with a background application which serves as the
>>host and target for the Apple events.
>Why is this not a good idea? It seems to be the only way in
>which this most useful task can be accomplished.

Sorry, I wrote that badly.  Sending an Apple event from a stand-alone
code resource is not a good idea.  Setting up a PPC link between
a code resource and an application and having the application send
the Apple event is a good idea, and is the DTS-sanctioned way to do
this.

Grobbins                 [e-mail]

Usual disclaimers apply.

---------------------------

End of C.S.M.P. Digest
**********************