Generalize filters as DSP effects

Add DSP flags to mixer and generalize the existing lowpass filter as a
DSP effect. Reverb and chorus effects (used in e.g. IMF) can be added
to the list later.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>

src/common.h

@@ -11,6 +11,7 @@ struct options {
 	int max_time;		/* max. replay time */
 	int mix;		/* channel separation */
 	int interp;		/* interpolation type */
+	int dsp;		/* dsp effects */
 	int loop;		/* loop module */
 	int random;		/* play in random order */
 	int verbose;

src/main.c

@@ -174,6 +174,7 @@ int main(int argc, char **argv)
 	options.mix = -1;
 	options.driver_id = NULL;
 	options.interp = XMP_INTERP_LINEAR;
+	options.dsp = XMP_DSP_LOWPASS;
 
 	get_options(argc, argv, &options);
 
@@ -301,6 +302,7 @@ int main(int argc, char **argv)
 		
 		if (xmp_player_start(handle, options.rate, options.format) == 0) {
 			xmp_mixer_set(handle, XMP_MIXER_INTERP, options.interp);
+			xmp_mixer_set(handle, XMP_MIXER_DSP, options.dsp);
 
 			xmp_set_position(handle, options.start);
 

src/options.c

@@ -157,11 +157,8 @@ void get_options(int argc, char **argv, struct options *options)
 			options->driver_id = optarg;
 			break;
 		case 'F':
-/* FIXME */
-#if 0
-			options->format |= XMP_FORMAT_NOFILTER;
+			options->dsp &= ~XMP_DSP_LOWPASS;;
 			break;
-#endif
 		case 'f':
 			options->rate = strtoul(optarg, NULL, 0);
 			break;