Delphi Graphics and Game Programming Exposed! with DirectX For versions 5.0-7.0:Sound and Music                       Search Tips   Advanced Search        Title Author Publisher ISBN    Please Select ----------- Artificial Intel Business & Mgmt Components Content Mgmt Certification Databases Enterprise Mgmt Fun/Games Groupware Hardware IBM Redbooks Intranet Dev Middleware Multimedia Networks OS Productivity Apps Programming Langs Security Soft Engineering UI Web Services Webmaster Y2K ----------- New Arrivals









Delphi Graphics and Game Programming Exposed with DirectX 7.0

by John Ayres

Wordware Publishing, Inc.

ISBN: 1556226373   Pub Date: 12/01/99














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Previous Table of Contents Next Listing 9-11: Playing CD Audio tracks procedure TfrmCDExample.FormCreate(Sender: TObject); var OpenParms: TMCI_Open_Parms; StatusParms: TMCI_Status_Parms; SetParms: TMCI_Set_Parms; InfoParms: TMCI_Info_Parms; UniqueID: array[0..255] of char; NumTracks, iCount: Integer; begin {open the cd audio playback device} OpenParms.lpstrDeviceType := ‘cdaudio’; MCISendCommand(0, MCI_OPEN, MCI_OPEN_TYPE or MCI_WAIT, Longint(@OpenParms)); {save a handle to the cd audio device} MCIDeviceID := OpenParms.wDeviceID; {determine if a CD is present in the drive} StatusParms.dwItem := MCI_STATUS_MEDIA_PRESENT ; MCISendCommand(MCIDeviceID, MCI_STATUS, MCI_WAIT or MCI_STATUS_ITEM, LongInt(@StatusParms)); if not LongBool(StatusParms.dwReturn) then begin ShowMessage(‘No CD is inserted in the CD-ROM drive. Please insert a CD’ + ‘and try again.’); Application.Terminate; end; {retrieve and display the unique CD identification number. this is for information only, and is not required for playing a track from the CD} InfoParms.dwRetSize := 255; InfoParms.lpstrReturn := UniqueID; MCISendCommand(MCIDeviceID, MCI_INFO, MCI_INFO_MEDIA_IDENTITY or MCI_WAIT, Longint(@InfoParms)); lblUniqueID.Caption := UniqueID; {set the time format for the CD audio device} SetParms.dwTimeFormat := MCI_FORMAT_TMSF; MCISendCommand(MCIDeviceID, MCI_SET, MCI_WAIT or MCI_SET_TIME_FORMAT, Longint(@SetParms)); {retrieve the number of tracks on the CD} StatusParms.dwItem := MCI_STATUS_NUMBER_OF_TRACKS ; MCISendCommand(MCIDeviceID, MCI_STATUS, MCI_WAIT or MCI_STATUS_ITEM, LongInt(@StatusParms)); NumTracks := StatusParms.dwReturn; {for each track, indicate its length} for iCount := 1 to NumTracks do begin StatusParms.dwTrack := iCount; StatusParms.dwItem := MCI_STATUS_LENGTH; MCISendCommand(MCIDeviceID, MCI_STATUS, MCI_WAIT or MCI_STATUS_ITEM or MCI_TRACK, LongInt(@StatusParms)); {when polling for length on a specific track, the value returned in the TMSF format is not exactly what you would expect. the Track macro returns minutes, the Minute macro returns seconds, the Second macro returns frames, and the Frame macro returns nothing. notice also that we are saving the exact length of each track in the Objects property} lbxCDTracks.Items.AddObject(‘Track +IntToStr(iCount)+’ - + ‘Format(%d:%.2d’, [MCI_TMSF_TRACK(StatusParms.dwReturn), MCI_TMSF_MINUTE(StatusParms.dwReturn)]), TObject(MCI_MAKE_TMSF( iCount,MCI_TMSF_TRACK(StatusParms.dwReturn), MCI_TMSF_MINUTE(StatusParms.dwReturn), MCI_TMSF_SECOND(StatusParms.dwReturn)))); end; end; procedure TfrmCDExample.lbxCDTracksDblClick(Sender: TObject); var PlayParms: TMCI_Play_Parms; begin {the user has indicated that another track should be played. therefore, stop any CD audio currently being output} MCISendCommand(MCIDeviceID, MCI_STOP, MCI_WAIT, 0); {the index of the selected item matches the index of the requested CD audio track. however, CD audio track indexes are one-based, and list box indexes are zero-based, so we must add a one to the selected item index. this indicates the starting track from which to begin playback} PlayParms.dwFrom := MCI_MAKE_TMSF(lbxCDTracks.ItemIndex+1, 0, 0, 0); {remember that we stored the actual length of each track in the Objects property along with the track name? since there is no track following the last track on the CD, we cannot tell the device to play the current track to the next track. to play the last track on the CD, we must indicate the exact length of that track. therefore, if we are playing the last track, we extract the track’s exact length from the Objects property. otherwise we can simply tell it to play to the next track} if lbxCDTracks.ItemIndex = lbxCDTracks.Items.Count-1 then PlayParms.dwTo := Longint(lbxCDTracks.Items.Objects[lbxCDTracks.ItemIndex]) else PlayParms.dwTo := MCI_MAKE_TMSF(lbxCDTracks.ItemIndex+2, 0, 0, 0); {instruct the CD audio device to play the indicated selection} MCISendCommand(MCIDeviceID, MCI_PLAY, MCI_FROM or MCI_TO, Longint(@PlayParms)); end; procedure TfrmCDExample.TimerTimer(Sender: TObject); var StatusParms: TMCI_Status_Parms; begin {poll the CD to determine the position of the current playback} StatusParms.dwItem := MCI_STATUS_POSITION; MCISendCommand(MCIDeviceID, MCI_STATUS, MCI_WAIT or MCI_STATUS_ITEM, LongInt(@StatusParms)); {the returned position value is in TMSF format. thus, we must extract the appropriate minutes and seconds values} lblPosition.Caption := ‘Format(%d:%.2d’, [MCI_TMSF_MINUTE(StatusParms.dwReturn), MCI_TMSF_SECOND(StatusParms.dwReturn)]); end; procedure TfrmCDExample.FormClose(Sender: TObject; var Action: TCloseAction); begin {the application is terminating, so stop any CD audio playback, and close the CD audio device} MCISendCommand(MCIDeviceID, MCI_STOP, MCI_WAIT, 0); MCISendCommand(MCIDeviceID, MCI_CLOSE, 0, 0); end; Previous Table of Contents Next Products |  Contact Us |  About Us |  Privacy  |  Ad Info  |  Home Use of this site is subject to certain Terms & Conditions, Copyright © 1996-2000 EarthWeb Inc. 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