文件列表:

PlayAudio\PlayAudio.cpp (20371, 2002-11-12)
PlayAudio\PlayAudio.dsp (4733, 2002-11-12)
PlayAudio\PlayAudio.dsw (541, 2002-11-12)
PlayAudio\playaudio.gif (2937, 2002-11-12)
PlayAudio\PlayAudio.rc (3530, 2002-11-12)
PlayAudio\PlayAudio.sln (918, 2002-11-12)
PlayAudio\PlayAudio.vcproj (4685, 2002-11-12)
PlayAudio\resource.h (1056, 2002-11-12)
PlayAudio (0, 2007-07-27)

//----------------------------------------------------------------------------- // // Sample Name: PlayAudio Sample // // Copyright (c) Microsoft Corporation. All rights reserved. // // GM/GS?Sound Set Copyright ?996, Roland Corporation U.S. // //----------------------------------------------------------------------------- Description =========== The PlayAudio sample shows how to load a segment and play it on an audiopath, how to use DirectMusic notifications, and how to change global performance parameters. Path ==== Source: E:\vc\PlayAudio User's Guide ============ Play the default segment, or load another wave, MIDI, or DirectMusic Producer segment file by clicking Open File. Adjust the volume by using the Master Volume slider. When using segments you can adjust the tempo by using the Tempo slider. Programming Notes ================= This and other DirectMusic samples uses the DirectMusic sample framework, CMusicManager and CMusicSegment to help encapsulate some of the common functionality of DirectMusic. The framework is contained in dmutil.cpp. This is how the sample works: * Upon WM_INITDIALOG. See OnInitDialog() 1. Create a Win32 event, g_hDMusicMessageEvent. This will be used by DirectMusic to signal the app whenever a DirectMusic notification comes in. 2. Create a help class CMusicManager called g_pMusicManager. 3. Initialize the CMusicManager class. This does the following. See CMusicManager::Initialize() in dmutil.cpp - Creates a IDirectMusicLoader8 using CoCreateInstance - Creates a IDirectMusicPerformance8 using CoCreateInstance - Calls IDirectMusicPerformance8::InitAudio to init DirectMusic using a standard audio path. 4. Call IDirectMusicPerformance8::AddNotificationType() passing in GUID_NOTIFICATION_SEGMENT. This will make DirectMusic tell us about any segment notifications that come in. This is needed to by this sample to know when the segment has ended. However DirectMusic games may not care when the segment has ended. 5. Call IDirectMusicPerformance8::SetNotificationHandle() passing in the Win32 event, g_hDMusicMessageEvent. This tells DirectMusic to signal this event when a notification is available. * Setting up the app message loop. See WinMain() 1. Create the dialog using CreateDialog(). 2. In a loop call MsgWaitForMultipleObjects() passing in g_hDMusicMessageEvent. This will tell us when g_hDMusicMessageEvent is signaled. Above we have told DirectMusic to signal this event whenever a DirectMusic notification has come in. 3. If WAIT_OBJECT_0 is returned, then call ProcessDirectMusicMessages(), See below for details. 4. If WAIT_OBJECT_0 + 1 is returned, then Windows msgs are available, so do standard msg processing using PeekMessage(). * When "Open File" is clicked. See OnOpenSoundFile() 1. Get the file name from using GetOpenFileName(). 2. Release the any old g_pMusicSegment. 3. Call CMusicManager::CollectGarbage(). See dmutil.cpp. This calls IDirectMusicLoader8::CollectGarbage which collects any garbage from any old segment that was present. This is done because some sophisticated segments, in particular ones that include segment trigger tracks or script tracks, may have a cyclic reference. For example, a segment trigger that references another segment that references the first segment, also via a segment trigger track. 4. Call CMusicManager::SetSearchDirectory(). See dmutil.cpp This calls IDirectMusicLoader8::SetSearchDirectory() passing in the GUID_DirectMusicAllTypes and a directory. This will tell DirectMusic where to look for files that are referenced inside of segments. 5. Call CMusicManager::CreateSegmentFromFile() to create a CMusicSegment called g_pMusicSegment from the file. See dmutil.cpp. This does the following: - Calls IDirectMusicLoader8::LoadObjectFromFile() to load the IDirectMusicSegment8 into pSegment. - Creates CMusicSegment passing in pSegment. - If the file is a pure MIDI file then it calls IDirectMusicSegment8::SetParam passing in GUID_StandardMIDIFile to DirectMusic this. This makes sure that patch changes are handled correctly. - If requested, it calls IDirectMusicSegment8::Download() this will download the segment's bands to the synthesizer. Some apps may want to wait before calling this to because the download allocates memory for the instruments. The more instruments currently downloaded, the more memory is in use by the synthesizer. * When "Play" is clicked. See OnPlayAudio() 1. If the UI says the sound should be looped, then call CMusicSegment::SetRepeats passing in DMUS_SEG_REPEAT_INFINITE, otherwise call CMusicSegment::SetRepeats passing in 0. 2. Call CMusicSegment::Play() which calls IDirectMusicPerformance8::PlaySegmentEx(). See dmutil.cpp. * Upon a DirectMusic notification. See ProcessDirectMusicMessages(). This sample wants to know if the primary segment has stopped playing so it can updated the UI so tell the user that they can play the sound again. This is rather complex, but typically apps will not need this functionality. Here is what has to be done: 1. Call IDirectMusicPerformance8::GetNotificationPMsg() in a loop to process each PMsg that has occurred. 2. Switch off the pPMsg->dwNotificationOption. This sample only handles it if its a DMUS_NOTIFICATION_SEGEND. This tells us that segment has ended. 3. Call QueryInterface on the pPMsg->punkUser, quering for a IDirectMusicSegmentState8. 4. Using the IDirectMusicSegmentState8, call GetSegment to get a IDirectMusicSegment* of the segment it refers to. This call may fail is the segment may have gone away before this notification was handled. 5. Call QueryInterface IDirectMusicSegment to get a IDirectMusicSegment8 6. Compare this pointer to the IDirectMusicSegment8 pointer in g_pMusicSegment, to see if this was the primary segment. This may not always be the case since segments can have segments enbedded inside of them, we only want handle when the primary segment has stopped playing. If it has, then update the UI 7. Cleanup all the interfaces.

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