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Timeline: Simplify fade application/avoid cast to long type.

This commit is contained in:
Jonathan Moore Liles 2012-06-06 23:43:36 -07:00
parent c6f6c57c05
commit f3505a84de
2 changed files with 20 additions and 41 deletions
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10
timeline/src/Audio_Region.H
View File

@ -60,17 +60,17 @@ public:
return length < rhs.length;
}
float increment ( void ) const
double increment ( void ) const
{
return 1.0f / (float)length;
return 1.0f / length;
}
/** Return gain for frame /index/ of /nframes/ on a gain curve
* of type /type/.*/
/* FIXME: calling a function per sample is bad, switching on
* type mid fade is bad. */
inline float
gain ( const float fi ) const
inline double
gain ( const double fi ) const
{
switch ( type )
{
@ -87,7 +87,7 @@ public:
}
}
void apply ( sample_t *buf, fade_dir_e dir, long start, nframes_t end, nframes_t nframes ) const;
void apply ( sample_t *buf, fade_dir_e dir, nframes_t start, nframes_t nframes ) const;
};
/* struct Fade_In : public Fade; */

51
timeline/src/Engine/Audio_Region.C
View File

@ -33,31 +33,18 @@
/** Apply a (portion of) fade from /start/ to /end/ assuming a
* buffer size of /nframes/. /start/ and /end/ are relative to the
* given buffer, and /start/ may be negative. */
/** Apply a (portion of) fade from /start/ to a buffer up to size /nframes/. */
void
Audio_Region::Fade::apply ( sample_t *buf, Audio_Region::Fade::fade_dir_e dir, long start, nframes_t end, nframes_t nframes ) const
Audio_Region::Fade::apply ( sample_t *buf, Audio_Region::Fade::fade_dir_e dir, nframes_t start, nframes_t nframes ) const
{
// printf( "apply fade %s: start=%ld end=%lu\n", dir == Fade::Out ? "out" : "in", start, end );
if ( ! nframes )
return;
const nframes_t i = start > 0 ? start : 0;
const nframes_t e = end > nframes ? nframes : end;
nframes_t n = nframes;
assert( i < nframes );
const float inc = increment();
float fi = ( i - start ) / (float)length;
// buf += i;
buf = &buf[ i ];
nframes_t n = e - i;
assert( i + n <= nframes );
const double inc = increment();
double fi = start / (double)length;
if ( dir == Fade::Out )
{
@ -94,18 +81,22 @@ Audio_Region::read ( sample_t *buf, nframes_t pos, nframes_t nframes, int channe
/* calculate offsets into file and sample buffer */
nframes_t sofs, ofs, cnt;
nframes_t sofs, /* offset into source */
ofs, /* offset into buffer */
cnt;
cnt = nframes;
if ( pos < r.start )
{
/* region starts somewhere after the beginning of this buffer */
sofs = 0;
ofs = r.start - pos;
cnt -= ofs;
}
else
{
/* region started before this buffer */
ofs = 0;
sofs = pos - r.start;
}
@ -161,34 +152,22 @@ Audio_Region::read ( sample_t *buf, nframes_t pos, nframes_t nframes, int channe
declick.type = Fade::Linear;
{
assert( cnt <= nframes );
Fade fade;
fade = declick < _fade_in ? _fade_in : declick;
/* do fade in if necessary */
if ( sofs < fade.length )
{
const long d = 0L - (long)sofs;
assert( cnt <= nframes );
fade.apply( buf + ofs, Fade::In, d, d + fade.length, cnt );
}
fade.apply( buf + ofs, Fade::In, sofs , cnt );
fade = declick < _fade_out ? _fade_out : declick;
/* do fade out if necessary */
// if ( start + cnt + fade.length > r.end )
if ( start + fade.length > ( r.offset + r.length ) )
{
const nframes_t d = ( r.offset + r.length ) - start;
assert( cnt <= nframes );
fade.apply( buf, Fade::Out, cnt + (long)d - fade.length, cnt + d, cnt );
if ( start + fade.length > r.offset + r.length )
fade.apply( buf, Fade::Out, ( start + fade.length ) - ( r.offset + r.length ), cnt );
}
}
// printf( "read %lu frames\n", cnt );
return cnt;
}