ibxm.Envelope Maven / Gradle / Ivy
package ibxm;
public class Envelope {
public boolean sustain, looped;
private int sustain_tick, loop_start_tick, loop_end_tick;
private int[] ticks, ampls;
public Envelope() {
set_num_points( 1 );
}
public void set_num_points( int num_points ) {
int point;
if( num_points <= 0 ) {
num_points = 1;
}
ticks = new int[ num_points ];
ampls = new int[ num_points ];
set_point( 0, 0, 0 );
}
/* When you set a point, all subsequent points are reset. */
public void set_point( int point, int tick, int ampl ) {
if( point >= 0 && point < ticks.length ) {
if( point == 0 ) {
tick = 0;
}
if( point > 0 ) {
if( tick < ticks[ point - 1 ] ) {
/* Simple guess at where the point is supposed to be.*/
tick += 256;
}
if( tick <= ticks[ point - 1 ] ) {
System.out.println( "Envelope: Point not valid (" + tick + " <= " + ticks[ point - 1 ] + ")");
tick = ticks[ point - 1 ] + 1;
}
}
ticks[ point ] = tick;
ampls[ point ] = ampl;
point += 1;
while( point < ticks.length ) {
ticks[ point ] = ticks[ point - 1 ] + 1;
ampls[ point ] = 0;
point += 1;
}
}
}
public void set_sustain_point( int point ) {
if( point < 0 ) {
point = 0;
}
if( point >= ticks.length ) {
point = ticks.length - 1;
}
sustain_tick = ticks[ point ];
}
public void set_loop_points( int start, int end ) {
if( start < 0 ) {
start = 0;
}
if( start >= ticks.length ) {
start = ticks.length - 1;
}
if( end < start || end >= ticks.length ) {
end = start;
}
loop_start_tick = ticks[ start ];
loop_end_tick = ticks[ end ];
}
public int next_tick( int tick, boolean key_on ) {
tick = tick + 1;
if( looped && tick >= loop_end_tick ) {
tick = loop_start_tick;
}
if( sustain && key_on && tick >= sustain_tick ) {
tick = sustain_tick;
}
return tick;
}
public int calculate_ampl( int tick ) {
int idx, point, delta_t, delta_a, ampl;
ampl = ampls[ ticks.length - 1 ];
if( tick < ticks[ ticks.length - 1 ] ) {
point = 0;
for( idx = 1; idx < ticks.length; idx++ ) {
if( ticks[ idx ] <= tick ) {
point = idx;
}
}
delta_t = ticks[ point + 1 ] - ticks[ point ];
delta_a = ampls[ point + 1 ] - ampls[ point ];
ampl = ( delta_a << IBXM.FP_SHIFT ) / delta_t;
ampl = ampl * ( tick - ticks[ point ] ) >> IBXM.FP_SHIFT;
ampl = ampl + ampls[ point ];
}
return ampl;
}
public void dump() {
int idx, tick;
for( idx = 0; idx < ticks.length; idx++ ) {
System.out.println( ticks[ idx ] + ", " + ampls[ idx ] );
}
for( tick = 0; tick < 222; tick++ ) {
System.out.print( calculate_ampl( tick ) + ", " );
}
}
}