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split out AdjustBalance, FadeSound

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This commit is contained in:
Glenn Maynard
2004-04-11 03:31:14 +00:00
parent 8e42e80208
commit 228f2bf858
1 changed files with 54 additions and 48 deletions
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stepmania/src/RageSound.cpp
+54 -48
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@@ -356,6 +356,55 @@ int RageSound::GetData( char *buffer, int frames )
return got;
}
/* Adjust the balance of buffer; fBalance is -1...+1. */
void AdjustBalance( Sint16 *buffer, int frames, float fBalance )
{
if( fBalance == 0 )
return; /* no change */
bool bSwap = fBalance < 0;
if( bSwap )
fBalance = -fBalance;
float fLeftFactors[2] ={ 1-fBalance, 0 };
float fRightFactors[2] =
{
SCALE( fBalance, 0, 1, 0.5f, 0 ),
SCALE( fBalance, 0, 1, 0.5f, 1 )
};
if( bSwap )
{
swap( fLeftFactors[0], fRightFactors[0] );
swap( fLeftFactors[1], fRightFactors[1] );
}
RAGE_ASSERT_M( channels == 2, ssprintf("%i", channels) );
for( int samp = 0; samp < frames; ++samp )
{
Sint16 l = Sint16(buffer[0]*fLeftFactors[0] + buffer[1]*fLeftFactors[1]);
Sint16 r = Sint16(buffer[0]*fRightFactors[0] + buffer[1]*fRightFactors[1]);
buffer[0] = l;
buffer[1] = r;
buffer += 2;
}
}
void FadeSound( Sint16 *buffer, int frames, float fStartVolume, float fEndVolume )
{
for( int samp = 0; samp < frames; ++samp )
{
float fVolPercent = SCALE( samp, 0, frames, fStartVolume, fEndVolume );
fVolPercent = clamp( fVolPercent, 0.f, 1.f );
for(int i = 0; i < channels; ++i)
{
*buffer = short(*buffer * fVolPercent);
buffer++;
}
}
}
/* Retrieve audio data, for mixing. At the time of this call, the frameno at which the
* sound will be played doesn't have to be known. Once committed, and the frameno
* is known, call CommitPCMData. size is in bytes.
@@ -446,56 +495,13 @@ bool RageSound::GetDataToPlay( int16_t *buffer, int size, int &sound_frame, int
* source.) If we don't know the length, don't fade. */
if( m_Param.m_FadeLength != 0 && m_Param.m_LengthSeconds != -1 )
{
Sint16 *p = (Sint16 *) buffer;
int this_position = position;
for(int samp = 0; samp < got_frames; ++samp)
{
const float fLastSecond = m_Param.m_StartSecond+m_Param.m_LengthSeconds;
const float fSecsUntilSilent = fLastSecond - float(this_position) / samplerate();
float fVolPercent = fSecsUntilSilent / m_Param.m_FadeLength;
fVolPercent = clamp(fVolPercent, 0.f, 1.f);
for(int i = 0; i < channels; ++i) {
*p = short(*p * fVolPercent);
p++;
}
this_position++;
}
const float fLastSecond = m_Param.m_StartSecond+m_Param.m_LengthSeconds;
const float fStartVolume = fLastSecond - float(position) / samplerate();
const float fEndVolume = fLastSecond - float(position+got_frames) / samplerate();
FadeSound( (Sint16 *) buffer, got_frames, fStartVolume, fEndVolume );
}
if( m_Param.m_Balance != 0 )
{
Sint16 *p = (Sint16 *) buffer;
float fBalance = m_Param.m_Balance;
bool bSwap = fBalance < 0;
if( bSwap )
fBalance = -fBalance;
float fLeftFactors[2] ={ 1-fBalance, 0 };
float fRightFactors[2] =
{
SCALE( fBalance, 0, 1, 0.5f, 0 ),
SCALE( fBalance, 0, 1, 0.5f, 1 )
};
if( bSwap )
{
swap( fLeftFactors[0], fRightFactors[0] );
swap( fLeftFactors[1], fRightFactors[1] );
}
RAGE_ASSERT_M( channels == 2, ssprintf("%i", channels) );
for( int samp = 0; samp < got_frames; ++samp )
{
Sint16 l = Sint16(p[0]*fLeftFactors[0] + p[1]*fLeftFactors[1]);
Sint16 r = Sint16(p[0]*fRightFactors[0] + p[1]*fRightFactors[1]);
p[0] = l;
p[1] = r;
p+=2;
}
}
AdjustBalance( (Sint16 *) buffer, got_frames, m_Param.m_Balance );
sound_frame = position;