public void set_point( int point, int tick, int ampl, boolean delta ) {
		if( point >= 0 && point < ticks.length ) {
			if( point == 0 ) {
				tick = 0;
			}
			if( point > 0 ) {
				if( delta ) tick += ticks[ point - 1 ];
				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;
			}
		}
	}