midimusic.cpp

游戏音频程序设计-Beginning.Game.Audio.Programming

// MIDIMusic.cpp: implementation of the CMIDIMusic class.
//
//////////////////////////////////////////////////////////////////////

#include "MIDIMusic.h"
#include "AudioManager.h"

#include <dmusicf.h>

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

namespace AudioEngine {

CMIDIMusic::CMIDIMusic(CAudioManager *mgr) : CDirectMusicSegment(mgr)
{

}

CMIDIMusic::~CMIDIMusic()
{

}

void CMIDIMusic::SetTempo(int beats_per_minute) 
{
  
  DMUS_TEMPO_PARAM Tempo;
  Tempo.dblTempo = beats_per_minute;
  ThrowIfFailed(m_Segment->SetParam(GUID_TempoParam, 0xFFFF, 0, 0, &Tempo),
    "CMIDIMusic::SetTempo: SetParam failed!");
  
  DMUS_TEMPO_PMSG* pTempo;
 
  ThrowIfFailed(m_Manager->GetPerformance()->AllocPMsg(sizeof(DMUS_TEMPO_PMSG), (DMUS_PMSG**)&pTempo),
    "CMIDIMusic::SetTempo: couldn't allocate PMsg!");

  // Cue the tempo event.
  ZeroMemory(pTempo, sizeof(DMUS_TEMPO_PMSG));
  pTempo->dwSize = sizeof(DMUS_TEMPO_PMSG);
  pTempo->dblTempo = beats_per_minute;
  pTempo->dwFlags = DMUS_PMSGF_REFTIME;
  pTempo->dwType = DMUS_PMSGT_TEMPO;
  ThrowIfFailed(m_Manager->GetPerformance()->SendPMsg((DMUS_PMSG*)pTempo),
    "CMIDIMusic::SetTempo: couldn't send PMsg!");
}

int CMIDIMusic::GetTempo()
{
  DMUS_TEMPO_PARAM Tempo;
  m_Segment->GetParam(GUID_TempoParam, 0xFFFF, 0, 0, NULL, &Tempo);
  return(Tempo.dblTempo);
}

} // namespace