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Play with curve interpolation.

This commit is contained in:
Jonathan Moore Liles 2008-04-28 20:06:45 -05:00
parent 311daf498c
commit f168b90e07
3 changed files with 23 additions and 84 deletions
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20
Timeline/Control_Sequence.C
View File

@ -319,7 +319,7 @@ Control_Sequence::handle ( int m )
static inline float
linear_interpolate ( float y1, float y2, float mu )
{
return y1 * (1 - mu) + y2 * mu;
return y1 + mu * ( y2 - y1 );
}
static inline float
@ -328,11 +328,21 @@ sigmoid_interpolate ( float y1, float y2, float mu )
return linear_interpolate( y1, y2, ( 1 - cos( mu * M_PI ) ) / 2 );
}
static inline float
quadratic_interpolate ( float y1, float y2, float mu )
{
return ( y1 * y1 ) * ( mu * mu ) + ( 2.0f * y1 * y2 ) * mu * ( y1 * y1 );
}
/* static inline float */
/* quadratic_interpolate ( float y1, float y2, float mu ) */
/* { */
/* } */
/* static inline float */
/* exponential_interpolate ( float y1, float y2, float mu ) */
/* { */
/* // return y1 * pow( y2 / y1, mu ); */
/* } */
/* THREAD: ?? */
@ -357,7 +367,9 @@ Control_Sequence::play ( sample_t *buf, nframes_t frame, nframes_t nframes )
for ( nframes_t i = frame - p1->when(); i < d; ++i )
{
*(buf++) = 1.0f - ( 2 * sigmoid_interpolate( p1->control(), p2->control(), i / (float)d ) );
// *(buf++) = 1.0f - ( 2 * sigmoid_interpolate( p1->control(), p2->control(), i / (float)d ) );
*(buf++) = 1.0f - ( 2 * linear_interpolate( p1->control(), p2->control(), i / (float)d ) );
// *(buf++) = 1.0f - ( 2 * quadratic_interpolate( p1->control(), p2->control(), i / (float)d ) );
if ( ! n-- )
return nframes;

7
Timeline/Control_Sequence.H
View File

@ -25,11 +25,18 @@
class Control_Sequence : public Sequence
{
public:
enum curve_type_e { Linear, Quadratic };
private:
Port *_output;
bool _highlighted;
curve_type_e _type;
void init ( void );

80
Timeline/Region.C
View File

@ -766,86 +766,6 @@ Region::Fade::apply ( sample_t *buf, Region::Fade::fade_dir_e dir, long start, n
*(buf++) *= gain( fi );
}
#if 0
/** Compute the gain value (0 to 1f) for a fade-in/out curve of /type/
* (LINEAR, QUADRAIC, CUBIC), of /nframes/ in length at point
* /offset/ */
static inline
float gain_on_curve ( int type, int dir, nframes_t nframes, nframes_t offset, nframes_t length )
{
float a, b;
/* FIXME: these first two sections should *definitely* be cached */
/* calculate coefficients */
if ( dir == FADE_OUT )
{
a = -1.0f / (double)nframes;
/* fixme why would we need to know the clip length? */
b = length / (double)nframes;
// b = nframes;
}
else
{
a = 1.0f / (double)nframes;
b = 0.0f;
}
float c[4];
/* interpolate points */
switch ( type )
{
case Linear:
c[1] = a;
c[0] = b;
break;
case Quadratic:
c[2] = a * a;
c[1] = 2.0f * a * b;
c[0] = b * b;
break;
case Cubic:
{
const float a2 = a * a;
const float b2 = b * b;
c[3] = a * a2;
c[2] = 3.0f * a2 * b;
c[1] = 3.0f * a * b2;
c[0] = b * b2;
break;
}
default:
printf( "unknown curve order\n" );
}
/* now get the gain for the given point */
const float f = offset;
const float f2 = f * f;
float g = 1.0f;
switch ( type )
{
case Linear:
g *= c[1] * f + c[0];
break;
case Quadratic:
g *= c[2] * f2 + c[1] * f + c[0];
break;
case Cubic:
g *= c[3] * f2 * f + c[2] * f2 + c[1] * f + c[0];
break;
}
printf( "gain for %lu is %f\n", offset, g );
return g;
}
#endif
/* THREAD: IO */
/** read the overlapping part of /channel/ at /pos/ for /nframes/ of
this region into /buf/, where /pos/ is in timeline frames */