Add --psg-mix=<empiric|linear> option (default linear)

README.md

@@ -84,6 +84,11 @@ Play options:
     -t, --track=<num>      set track number
     -f, --frequency=<num>  set audio frequency in Hz (default 44100)
 
+    --psg-mix=<empiric|linear>
+                           empiric mixes the three PSG channels as measured
+                           on Atari ST hardware; linear sums the channels to
+                           produce a cleaner sound (default linear)
+
 Disassembly options:
 
     --disassemble          disassemble SNDH file and exit; may be combined

doc/psgplay.1

@@ -75,6 +75,11 @@ Set track number.
 .BR \-f ", " \-\-frequency "=<" \fIfrequency\fR ">"
 Set audio frequency in Hz (default 44100).
 
+.TP
+.BR \-\-psg-mix "=<" \fIempiric\fR "|" \fIlinear\fR ">"
+Empiric mixes the three PSG channels as measured on Atari ST hardware; linear
+sums the channels to produce a cleaner sound (default linear).
+
 .RE
 
 Disassembly options:

include/system/unix/option.h

@@ -9,6 +9,7 @@
 #include <stdbool.h>
 
 #include "atari/trace.h"
+#include "psgplay/stereo.h"
 
 #define OPTION_TIME_UNDEFINED -1
 #define OPTION_STOP_NEVER     -2
@@ -36,6 +37,8 @@ struct options {
 	int track;
 	int frequency;
 
+	const char *psg_mix;
+
 	const char *input;
 
 	struct trace_mode trace;
@@ -50,6 +53,8 @@ bool command_mode_option(void);
 
 bool text_mode_option(void);
 
+psgplay_digital_to_stereo_cb psg_mix_option(void);
+
 struct options *parse_options(int argc, char **argv);
 
 int option_verbosity(void);

system/unix/command-mode.c

@@ -101,6 +101,11 @@ void command_replay(const struct options *options, struct file file,
 		options->track, options->frequency);
 	ssize_t sample_count = 0;
 
+	if (!pp)
+		pr_fatal_error("%s: failed to init PSG play\n", progname);
+
+	psgplay_digital_to_stereo_callback(pp, psg_mix_option(), NULL);
+
 	for (;;) {
 		struct psgplay_stereo buffer[256];
 

system/unix/option.c

@@ -64,6 +64,11 @@ static void help(FILE *file)
 "    -t, --track=<num>      set track number\n"
 "    -f, --frequency=<num>  set audio frequency in Hz (default 44100)\n"
 "\n"
+"    --psg-mix=<empiric|linear>\n"
+"                           empiric mixes the three PSG channels as measured\n"
+"                           on Atari ST hardware; linear sums the channels to\n"
+"                           produce a cleaner sound (default linear)\n"
+"\n"
 "Disassembly options:\n"
 "\n"
 "    --disassemble          disassemble SNDH file and exit; may be combined\n"
@@ -169,6 +174,18 @@ TRACE_DEVICE(TRACE_DEVICE_OPT)
 	return (struct trace_mode) { .m = m };
 }
 
+psgplay_digital_to_stereo_cb psg_mix_option(void)
+{
+	if (strcmp(option.psg_mix, "empiric") == 0)
+		return psgplay_digital_to_stereo_empiric;
+	if (strcmp(option.psg_mix, "linear") == 0)
+		return psgplay_digital_to_stereo_linear;
+
+	pr_fatal_error("unknown PSG mix: %s\n", option.psg_mix);
+
+	return NULL;
+}
+
 struct options *parse_options(int argc, char **argv)
 {
 	static const struct option options[] = {
@@ -188,6 +205,8 @@ struct options *parse_options(int argc, char **argv)
 		{ "track",               required_argument, NULL, 0 },
 		{ "frequency",           required_argument, NULL, 0 },
 
+		{ "psg-mix",             required_argument, NULL, 0 },
+
 		{ "disassemble",         no_argument,       NULL, 0 },
 		{ "disassemble-header",  no_argument,       NULL, 0 },
 		{ "disassemble-address", no_argument,       NULL, 0 },
@@ -204,6 +223,7 @@ struct options *parse_options(int argc, char **argv)
 
 	option.track = -1;
 	option.frequency = 44100;
+	option.psg_mix = "linear";
 
 	for (;;) {
 		int index = 0;
@@ -242,6 +262,8 @@ struct options *parse_options(int argc, char **argv)
 				goto opt_t;
 			else if (OPT("frequency"))
 				goto opt_f;
+			else if (OPT("psg-mix"))
+				option.psg_mix = optarg;
 
 			else if (OPT("trace"))
 				option.trace = trace_option(optarg);

system/unix/text-mode.c

@@ -47,19 +47,29 @@ struct tty_arg {
 	struct sample_buffer *sb;
 };
 
+static struct psgplay *psgplay_init__(const void *data,
+	size_t size, int track, int frequency)
+{
+	struct psgplay *pp = psgplay_init(data, size, track, frequency);
+
+	if (!pp)
+		pr_fatal_error("Failed to init PSG play\n");
+
+	psgplay_digital_to_stereo_callback(pp, psg_mix_option(), NULL);
+
+	return pp;
+}
+
 static struct sample_buffer sample_buffer_init(const void *data, size_t size,
 	const char *option_output, int track, int frequency,
 	const struct output *output)
 {
 	struct sample_buffer sb = {
-		.pp = psgplay_init(data, size, track, frequency),
+		.pp = psgplay_init__(data, size, track, frequency),
 		.output = output,
 		.output_arg = output->open(option_output, frequency, true),
 	};
 
-	if (!sb.pp)
-		pr_fatal_error("Failed to init PSG play\n");
-
 	return sb;
 }
 
@@ -98,9 +108,7 @@ static bool sample_buffer_play(struct sample_buffer *sb,
 {
 	BUG_ON(sb->pp);
 
-	sb->pp = psgplay_init(data, size, track, frequency);
-	if (!sb->pp)
-		return false;
+	sb->pp = psgplay_init__(data, size, track, frequency);
 
 	return true;
 }