DirectSound specific question with masm V8 and Directx 8

[edkedk]

Hi guys,

I am have a problem here.
I have a masm version 8 environment, with the DirectX 8 header and lib files. All ok so far.
The only problem I have is I want to use the API invoke "GetCurrentPosition"  to retrieve the offset in bytes from the play-cursor and write-cursor in a buffered-loop scenario, wher I want to put my sample bytes in manualy via the CPU.
The invoke want 3 input parameters, but when I look on msdn online, directx8 function "GetCurrentPosition" needs only two, only two offsets where two dwords are put as a result by win32 api.
What kind of input parameter is the 1st one in the invoke command exactly?    If i give it a value of 0 or NULL, my app. crashes.

Here is a small snipet of code (all comments I do not use as instructions now, I found a directsound example for masm many years ago, I dont know anymore where I got this example from).

;       mov   eax, sizeof(pcm_sound);
;   mov   ecx,0
;   mul   ecx
;   mov   ecx, eax
DSBINVOKE   GetCurrentPosition,sound_fx[ecx].dsbuffer,ADDR ds_pos_play, ADDR ds_pos_write

It is the part "sound_fx[ecx].dsbuffer" I need explanation of.
When I look at the invoke line, i guess it needs a pointer (dword) to a directsound buffer, right ?
But there stops my knowledge. For masm32 there is not so much to find with examples with DirectX. Especially with DirectSound, is difficult to find something.

By the way, I want to use this for my Commodore 64 emulator, to make the sound better (I have lots of strange weird sounds because now sometimes I write byte to the buffer where the playcursor is. That is bad. I want to enhance the sound output quality. I wan to do that by check at regular intervals the playcursor and writecursor and then see where I can safely write my samplebyte to be played.

The original website I used years ago was:
http://www.gamedev.net/reference/articles/article909.asp

Unfortunately the webpage does not exist anymore.


A part of my dsound.inc file I use for including:

   ;=======================================
   ; The DirectSoundBuffer interface
   ;=======================================
IDirectSoundBufferVtbl   STRUC
   ; IUnknown methods
   STDMETHOD QueryInterface, :PTR IDirectSoundBuffer, :PTR, :PTR PTR
   STDMETHOD AddRef, :PTR IDirectSoundBuffer
   STDMETHOD Release, :PTR IDirectSoundBuffer
   ; IDirectSoundBuffer methods
   STDMETHOD GetCaps, :PTR IDirectSoundBuffer,:DWORD
   STDMETHOD GetCurrentPosition, :PTR IDirectSoundBuffer,:DWORD,:DWORD                                                  <=============== THIS ONE !
   STDMETHOD GetFormat, :PTR IDirectSoundBuffer,:DWORD,:DWORD,:DWORD
   STDMETHOD GetVolume, :PTR IDirectSoundBuffer,:DWORD
   STDMETHOD GetPan, :PTR IDirectSoundBuffer,:DWORD
   STDMETHOD GetFrequency, :PTR IDirectSoundBuffer,:DWORD
   STDMETHOD GetStatus, :PTR IDirectSoundBuffer,:DWORD
   STDMETHOD Initialize, :PTR IDirectSoundBuffer,:DWORD,:DWORD
   STDMETHOD mLock, :PTR IDirectSoundBuffer,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD
   STDMETHOD Play, :PTR IDirectSoundBuffer,:DWORD,:DWORD,:DWORD
   STDMETHOD SetCurrentPosition, :PTR IDirectSoundBuffer,:DWORD




Hope someone can help me out with this !
Thanks in advance.
Merry Christmas and a happy coding year in 2009 !

Cheers,

Erik de Keijzer
The Netherlands

[Tedd]

It's a 'method' rather than just a flat function.
The first (hidden) parameter is the instance of the object you want the method to act upon - the sound buffer, in this case. Otherwise, how does it know which sound buffer you want to get the current position of?
You must've either gained or created a sound buffer, so for any methods you want to call on that buffer, you must supply it in the calls to those methods (as the first parameter; even though it's not listed in the api docs, because they're meant for C++ where it's done automatically for you by the compiler.)

[Siekmanski]

Hello Folks

This source code for streaming DirectSound buffers maybe of some interrest for you
It also includes the "GetCurrentPosition" function.

http://members.home.nl/siekmanski/DSound_Streaming.zip

greetings and a happy newyear

Siekmanski, (also from The Netherlands)   :lol

Inserted missing dir.

[u]

Btw, this here is MASM code:

Code Select Expand


EnterHostedClass
class IASIO,,C++ compatible
; this one needs special handing, since it's a mixture of COM and C++ classes
;virtual QueryInterface ; this one's taken from the real Destructor
virtual AddRef
virtual Release:pThis

virtual init:sysHandle
virtual getDriverName:char *name
virtual getDriverVersion:
virtual getErrorMessage:char *string
virtual start:
virtual stop:
virtual getChannels:long *numInputChannels, long *numOutputChannels
virtual getLatencies:long *inputLatency, long *outputLatency
virtual getBufferSize:long *minSize, long *maxSize,long *preferredSize, long *granularity
virtual canSampleRate:ASIOSampleRate sampleRate
virtual getSampleRate:ASIOSampleRate *sampleRate
virtual setSampleRate:ASIOSampleRate sampleRate
virtual getClockSources:ASIOClockSource *clocks, long *numSources
virtual setClockSource:long reference
virtual getSamplePosition:ASIOSamples *sPos, ASIOTimeStamp *tStamp
virtual getChannelInfo:ASIOChannelInfo *info
virtual createBuffers:ASIOBufferInfo *bufferInfos, long numChannels,long bufferSize, ASIOCallbacks *callbacks
virtual disposeBuffers:
virtual controlPanel:
virtual future:long selector,void *opt
virtual outputReady:
endclass
LeaveHostedClass

ASIOChannelInfo struct
channel dd ?
isInput dd ?
isActive dd ?
channelGroup dd ?
sampleType dd ?
chanName db 32 dup (?)
ASIOChannelInfo ends

ASIOCallbacks struct
bufferSwitch dd ?
sampleRateDidChange dd ?
asioMessage dd ?
bufferSwitchTimeInfo dd ?
ASIOCallbacks ends
...
.data
pAsioDrv dd 0
set pAsioDrv as IASIO
.code
...
ASIO_GetSampleRate proc uses ebx ecx edx
local dblSamRate:real8,intSamRate:DWORD
pcall pAsioDrv.getSampleRate,addr dblSamRate
fld dblSamRate
fistp intSamRate
mov eax,intSamRate
ret
ASIO_GetSampleRate endp