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