# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1661148848 25200
# Node ID 2648081f3100b3ccd9a14db4b53e3a3d6b204495
# Parent  40290a92388632997ac1e6e99c9749fb794cf774
Implement Game Gear PSG panning

diff -r 40290a923886 -r 2648081f3100 psg.c
--- a/psg.c	Sun Aug 21 22:56:32 2022 -0700
+++ b/psg.c	Sun Aug 21 23:14:08 2022 -0700
@@ -13,11 +13,12 @@
 void psg_init(psg_context * context, uint32_t master_clock, uint32_t clock_div)
 {
 	memset(context, 0, sizeof(*context));
-	context->audio = render_audio_source("PSG", master_clock, clock_div, 1);
+	context->audio = render_audio_source("PSG", master_clock, clock_div, 2);
 	context->clock_inc = clock_div;
 	for (int i = 0; i < 4; i++) {
 		context->volume[i] = 0xF;
 	}
+	context->pan = 0xFF;
 }
 
 void psg_free(psg_context *context)
@@ -110,18 +111,33 @@
 			}
 		}
 
-		int16_t accum = 0;
+		int16_t left_accum = 0, right_accum = 0;
+		uint8_t pan_left = 0x10, pan_right = 0x1;
 
 		for (int i = 0; i < 3; i++) {
 			if (context->output_state[i]) {
-				accum += volume_table[context->volume[i]];
+				int16_t value = volume_table[context->volume[i]];
+				if (context->pan & pan_left) {
+					left_accum += value;
+				}
+				if (context->pan & pan_right) {
+					right_accum += value;
+				}
+				pan_left <<= 1;
+				pan_right <<= 1;
 			}
 		}
 		if (context->noise_out) {
-			accum += volume_table[context->volume[3]];
+			int16_t value = volume_table[context->volume[3]];
+			if (context->pan & pan_left) {
+				left_accum += value;
+			}
+			if (context->pan & pan_right) {
+				right_accum += value;
+			}
 		}
 
-		render_put_mono_sample(context->audio, accum);
+		render_put_stereo_sample(context->audio, left_accum, right_accum);
 
 		context->cycles += context->clock_inc;
 	}
diff -r 40290a923886 -r 2648081f3100 psg.h
--- a/psg.h	Sun Aug 21 22:56:32 2022 -0700
+++ b/psg.h	Sun Aug 21 23:14:08 2022 -0700
@@ -25,6 +25,7 @@
 	uint8_t  noise_use_tone;
 	uint8_t  noise_type;
 	uint8_t  latch;
+	uint8_t  pan;
 } psg_context;
 
 
diff -r 40290a923886 -r 2648081f3100 sms.c
--- a/sms.c	Sun Aug 21 22:56:32 2022 -0700
+++ b/sms.c	Sun Aug 21 23:14:08 2022 -0700
@@ -212,16 +212,12 @@
 	//TODO: implement link port
 	return vcontext;
 }
-
-static uint8_t psg_pan_read(uint32_t location, void *vcontext)
-{
-	//TODO: implement PSG pan
-	return 0xFF;
-}
-
 static void *psg_pan_write(uint32_t location, void *vcontext, uint8_t value)
 {
-	//TODO: implement PSG pan
+	z80_context *z80 = vcontext;
+	sms_context *sms = z80->system;
+	psg_run(sms->psg, z80->Z80_CYCLE);
+	sms->psg->pan = value;
 	return vcontext;
 }
 static memmap_chunk io_map[] = {
@@ -233,7 +229,7 @@
 
 static memmap_chunk io_gg[] = {
 	{0x00, 0x07, 0xFF, .read_8 = gg_io_read, .write_8 = gg_io_write},
-	{0x07, 0x08, 0xFF, .read_8 = psg_pan_read, .write_8 = psg_pan_write},
+	{0x07, 0x08, 0xFF, .write_8 = psg_pan_write},
 	{0x08, 0x40, 0xFF, .write_8 = memory_io_write},
 	{0x40, 0x80, 0xFF, .read_8 = hv_read, .write_8 = sms_psg_write},
 	{0x80, 0xC0, 0xFF, .read_8 = vdp_read, .write_8 = vdp_write},