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 Of particular interest to the game programmer is the value of the dwFlags member. This member contains a combination of one or more flags that indicate device capabilities. Specifically, if the DSCAPS_EMULDRIVER flag is included in this value, a DirectSound driver is not actually present in the system, and all DirectSound functionality is being emulated. This means that no hardware acceleration is available, secondary sound buffers can only be created in system memory, and playback latency will be higher. See the example program in Listing 9-3 for a list of available flags. The TDSCaps structure is defined as: TDSCaps = packed record dwSize: DWORD; // the size of the structure, in bytes dwFlags: DWORD; // capability flags dwMinSecondarySampleRate: DWORD; // minimum sample rate for secondary buffers in hardware dwMaxSecondarySampleRate: DWORD; // maximum sample rate for secondary buffers in hardware dwPrimaryBuffers: DWORD; // number of primary buffers (always 1) dwMaxHwMixingAllBuffers: DWORD; // maximum number of hardware buffers dwMaxHwMixingStaticBuffers: DWORD; // maximum number of static hardware buffers dwMaxHwMixingStreamingBuffers: DWORD; // maximum number of streaming hardware buffers dwFreeHwMixingAllBuffers: DWORD; // number of free hardware buffers dwFreeHwMixingStaticBuffers: DWORD; // number of free static hardware buffers dwFreeHwMixingStreamingBuffers: DWORD;// number of free streaming hardware buffers dwMaxHw3DAllBuffers: DWORD; // maximum number of 3-D hardware buffers dwMaxHw3DStaticBuffers: DWORD; // maximum number of 3-D static hardware buffers dwMaxHw3DStreamingBuffers: DWORD; // maximum number of 3-D streaming hardware buffers dwFreeHw3DAllBuffers: DWORD; // number of free 3-D hardware buffers dwFreeHw3DStaticBuffers: DWORD; // number of free 3-D static hardware buffers dwFreeHw3DStreamingBuffers: DWORD; // number of free 3-D streaming hardware buffers dwTotalHwMemBytes: DWORD; // total hardware memory, in bytes dwFreeHwMemBytes: DWORD; // free hardware memory, in bytes dwMaxContigFreeHwMemBytes: DWORD; // largest contiguous block of free hardware memory, in bytes dwUnlockTransferRateHwBuffers: DWORD; // rate of data transfer to hardware buffers, in kilobytes per second dwPlayCpuOverheadSwBuffers: DWORD; // percentage of CPU cycles used to mix software buffers dwReserved1: DWORD; // reserved, not used dwReserved2: DWORD; // reserved, not used end; The following example demonstrates how to create the DirectSound object, set its cooperative level, and retrieve audio hardware capabilities. Listing 9-3: Creating DirectSound and retrieving hardware capabilities procedure TForm1.FormCreate(Sender: TObject); var DXSound: IDirectSound; DevCaps: TDSCaps; begin {create the DirectSound object} DirectSoundCreate(nil, DXSound, nil); {set its cooperative level to the lowest setting, as we only need to retrieve device capabilities} DXSound.SetCooperativeLevel(Handle, DSSCL_NORMAL); {initialize the TDSCaps structure} FillChar(DevCaps, SizeOf(TDSCaps), 0); DevCaps.dwSize := SizeOf(TDSCaps); {retrieve the capabilities of the audio hardware} DXSound.GetCaps(DevCaps); {display general device capabilities} with lbxDevCaps.Items do begin Add(‘General driver capabilities -’); Add(‘’) if (DevCaps.dwFlags and DSCAPS_CERTIFIED) = DSCAPS_CERTIFIED then Add(‘Driver tested and certified by Microsoft’); if (DevCaps.dwFlags and DSCAPS_CONTINUOUSRATE) = DSCAPS_CONTINUOUSRATE then Add(‘Supports all sample rates between min and max’); if (DevCaps.dwFlags and DSCAPS_EMULDRIVER) = DSCAPS_EMULDRIVER then Add(‘No DirectSound driver detected’); if (DevCaps.dwFlags and DSCAPS_PRIMARY16BIT) = DSCAPS_PRIMARY16BIT then Add(‘Supports 16-bit primary buffer’); if (DevCaps.dwFlags and DSCAPS_PRIMARY8BIT) = DSCAPS_PRIMARY8BIT then Add(‘Supports 8-bit primary buffer’); if (DevCaps.dwFlags and DSCAPS_PRIMARYMONO) = DSCAPS_PRIMARYMONO then Add(‘Supports a 1-channel primary buffer’); if (DevCaps.dwFlags and DSCAPS_PRIMARYSTEREO) = DSCAPS_PRIMARYSTEREO then Add(‘Supports a 2-channel primary buffer’); if (DevCaps.dwFlags and DSCAPS_SECONDARY16BIT) = DSCAPS_SECONDARY16BIT then Add(‘Supports 16-bit hardware mixed secondary buffers’); if (DevCaps.dwFlags and DSCAPS_SECONDARY8BIT) = DSCAPS_SECONDARY8BIT then Add(‘Supports 8-bit hardware mixed secondary buffers’); if (DevCaps.dwFlags and DSCAPS_SECONDARYMONO) = DSCAPS_SECONDARYMONO then Add(‘Supports 1 channel hardware mixed secondary buffers’); if (DevCaps.dwFlags and DSCAPS_SECONDARYSTEREO)=DSCAPS_SECONDARYSTEREO then Add(‘Supports 2 channel hardware mixed secondary buffers’); Add(‘Number of primary buffers: ’ +IntToStr(DevCaps.dwPrimaryBuffers)); Add(‘Software mixing CPU overhead:’ + IntToStr(‘DevCaps.dwPlayCpuOverheadSwBuffers’)+‘%’); {if the driver is a true DirectSound driver, it can take advantage of any hardware acceleration, so display hardware-specific attributes} if (DevCaps.dwFlags and DSCAPS_EMULDRIVER) DSCAPS_EMULDRIVER then begin Add(‘’); Add(‘’); Add(‘Hardware specific capabilities -’); Add(‘’); Add(Minimum secondary hardware buffer sample rate: + IntToStr(DevCaps.dwMinSecondarySampleRate)); Add(Maximum secondary hardware buffer sample rate: + IntToStr(DevCaps.dwMaxSecondarySampleRate)); Add(Maximum hardware buffers: + IntToStr(DevCaps.dwMaxHwMixingAllBuffers)); Add(Maximum static hardware buffers: + IntToStr(DevCaps.dwMaxHwMixingStaticBuffers)); Add(Maximum streaming hardware buffers: + IntToStr(DevCaps.dwMaxHwMixingStreamingBuffers)); Add(‘Free hardware buffers:’+IntToStr(DevCaps.dwFreeHwMixingAllBuffers)); Add(Free static hardware buffers: + IntToStr(DevCaps.dwFreeHwMixingStaticBuffers)); Add(Free streaming hardware buffers: + IntToStr(DevCaps.dwFreeHwMixingStreamingBuffers)); Add(Maximum 3-D hardware buffers: + IntToStr(DevCaps.dwMaxHw3DAllBuffers)); Add(Maximum 3-D static hardware buffers: + IntToStr(DevCaps.dwMaxHw3DStaticBuffers)); Add(Maximum 3-D streaming hardware buffers: + IntToStr(DevCaps.dwMaxHw3DStreamingBuffers)); Add(Free 3-D hardware buffers: +IntToStr(DevCaps.dwFreeHw3DAllBuffers)); Add(Free 3-D static hardware buffers: + IntToStr(DevCaps.dwFreeHw3DStaticBuffers)); Add(Free 3-D streaming hardware buffers: + IntToStr(DevCaps.dwFreeHw3DStreamingBuffers)); Add(Total hardware memory: +IntToStr(DevCaps.dwTotalHwMemBytes)+ ‘bytes’); Add(‘Free hardware memory: ’ +IntToStr(DevCaps.dwFreeHwMemBytes)+ ‘bytes’); Add(Maximum contiguous free hardware memory: + IntToStr(DevCaps.dwMaxContigFreeHwMemBytes)+ ‘ bytes’); Add(‘Data transfer rate:’ + IntToStr(DevCaps.dwUnlockTransferRateHwBuffers)+ ‘kb per second’); end; end; end; Figure 9-4:  The audio hardware capabilities 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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