Add LED protocol v2 fade tracking

README.md

@@ -81,20 +81,22 @@ LOAD deliberately overwrites an occupied slot (remove first, then load), matchin
 
 ### LED mirror (`GET_LED`)
 
-LOAD/REMOVE/MOVE are fire-and-forget; `GET_LED` is the one command that answers. It returns a fixed 30-byte snapshot of what the game has the three LED regions doing:
+LOAD/REMOVE/MOVE are fire-and-forget; `GET_LED` is the one command that answers. It returns a fixed 40-byte snapshot (protocol version 2) of what the game has the three LED regions doing:
 
 ```
 [0]   0x4C  'L' magic
 [1]   serial       increments whenever any region actually changes
-[2]   0x03         region count
-[3..] 3 x 9 bytes: pad, mode, r, g, b, on_ms, off_ms, count, speed_ms
+[2]   0x02         protocol version
+[3]   0x03         region count
+[4..] 3 x 12 bytes: pad, mode, r, g, b, from_r, from_g, from_b, on_ms, off_ms, count, speed_ms
 ```
 
 | Field | Meaning |
 |---|---|
 | `pad` | LED region — `1` centre, `2` left, `3` right |
 | `mode` | `0` off, `1` solid, `2` flash, `3` fade |
 | `r`, `g`, `b` | The colour the game set, verbatim |
+| `from_r`, `from_g`, `from_b` | For a fade, the colour the pad was already showing when the command landed; the real toypad cross-fades from it to `r/g/b` rather than ramping one colour's brightness |
 | `on_ms` / `off_ms` | Flash on and off durations, in Toypad ticks (~40ms each) |
 | `count` | Cycle count; `0` means "until the next command" (`0xFF` on the wire is normalized to `0`) |
 | `speed_ms` | Fade tick time |
@@ -103,7 +105,7 @@ The emulated Toypad builds this snapshot in `handle_led_command`, parsing the ga
 
 The **serial** only advances when a command actually changes a region's state — re-sending an identical command leaves it alone. A polling client can therefore skip snapshots it has already applied and never restart a flash mid-cycle.
 
-This is byte-for-byte the same snapshot the Cemu fork returns, so LegoToypad's LED mirror works against either emulator with no changes.
+This is the protocol version 2 snapshot the Cemu and shadPS4 listeners also return, so LegoToypad's LED mirror works against this emulator with no changes. (Version 1 was a 30-byte reply with no version byte and no `from_r/g/b`; the app now rejects it, which is why RPCS3 needed this update.)
 
 ## Code map
 

rpcs3/Emu/Io/Dimensions.cpp

@@ -630,6 +630,10 @@ void dimensions_toypad::set_led_state(u8 pad, u8 mode, u8 r, u8 g, u8 b, u8 on_m
 	auto apply = [&](u8 target_pad)
 	{
 		led_pad_state& state = m_led_state[led_pad_index(target_pad)];
+		// A fade's "from" colour is whatever the pad was already showing (or
+		// already fading towards) the moment this command lands, so a fade
+		// issued mid-fade still anchors to something on-screen.
+		const u8 from_r = state.r, from_g = state.g, from_b = state.b;
 		if (state.mode == mode && state.r == r && state.g == g && state.b == b &&
 			state.on_ms == on_ms && state.off_ms == off_ms && state.count == count && state.speed_ms == speed_ms)
 			return; // unchanged - don't bump the poll serial
@@ -638,6 +642,12 @@ void dimensions_toypad::set_led_state(u8 pad, u8 mode, u8 r, u8 g, u8 b, u8 on_m
 		state.r = r;
 		state.g = g;
 		state.b = b;
+		if (mode == 3) // Fade: remember the pre-command colour to cross-fade from
+		{
+			state.from_r = from_r;
+			state.from_g = from_g;
+			state.from_b = from_b;
+		}
 		state.on_ms = on_ms;
 		state.off_ms = off_ms;
 		state.count = count;

rpcs3/Emu/Io/Dimensions.h

@@ -31,14 +31,17 @@ class dimensions_toypad
 	std::optional<std::array<u8, 32>> pop_added_removed_response();
 
 	// Mirror a pad region's LED state ("keystone puzzle" glow). Same encoding
-	// and wire snapshot as the Cemu fork, so the LegoToypad controller app can
-	// render the pads glowing for RPCS3 too. mode: 0 off, 1 solid, 2 flash,
-	// 3 fade; pad: 1=center, 2=left, 3=right.
+	// and wire snapshot as the Cemu/RPCS3 protocol version 2, so the LegoToypad
+	// controller app can render the pads glowing for RPCS3 too. mode: 0 off,
+	// 1 solid, 2 flash, 3 fade; pad: 1=center, 2=left, 3=right. from_r/g/b is
+	// the colour the pad was already showing when a fade command landed - the
+	// real toypad cross-fades between that and r/g/b, not one colour's brightness.
 	struct led_pad_state
 	{
 		u8 pad = 0;
 		u8 mode = 0;
 		u8 r = 0, g = 0, b = 0;
+		u8 from_r = 0, from_g = 0, from_b = 0;
 		u8 on_ms = 0, off_ms = 0, count = 0, speed_ms = 0;
 	};
 	void handle_led_command(const u8* buf, u32 buf_size);

rpcs3/Emu/Io/DimensionsListener.cpp

@@ -41,6 +41,11 @@ namespace
 	std::atomic<bool> g_listener_running{false};
 	std::atomic<socket_t> g_listen_sock{invalid_sock};
 	constexpr auto move_pickup_delay = std::chrono::milliseconds(500);
+	// LED snapshot protocol version. v2 is a 40-byte reply that adds the
+	// pre-fade colour (from_r/g/b) alongside the target colour, so a client can
+	// render the real toypad's two-colour cross-fade. v1 was 30 bytes with no
+	// version byte; the companion app now requires v2.
+	constexpr u8 led_protocol_version = 2;
 
 #ifdef _WIN32
 	std::thread g_picker_thread;
@@ -231,22 +236,30 @@ namespace
 			const auto states = g_dimensionstoypad.get_led_states();
 			const u8 serial = g_dimensionstoypad.get_led_serial();
 
-			u8 response[3 + 3 * 9] = {};
+			// Wire format v2: { 'L', serial, protocol version, region count,
+			// then 3 regions x 12 bytes: pad, mode, r, g, b, from_r, from_g,
+			// from_b, on_ms, off_ms, count, speed_ms }. from_r/g/b is the
+			// pre-fade colour; see dim_listener_log and Dimensions.h.
+			u8 response[4 + 3 * 12] = {};
 			response[0] = 0x4C; // 'L' magic
 			response[1] = serial;
-			response[2] = 0x03; // region count
+			response[2] = led_protocol_version;
+			response[3] = 0x03; // region count
 			for (usz i = 0; i < 3; ++i)
 			{
-				const usz off = 3 + i * 9;
+				const usz off = 4 + i * 12;
 				response[off + 0] = states[i].pad;
 				response[off + 1] = states[i].mode;
 				response[off + 2] = states[i].r;
 				response[off + 3] = states[i].g;
 				response[off + 4] = states[i].b;
-				response[off + 5] = states[i].on_ms;
-				response[off + 6] = states[i].off_ms;
-				response[off + 7] = states[i].count;
-				response[off + 8] = states[i].speed_ms;
+				response[off + 5] = states[i].from_r;
+				response[off + 6] = states[i].from_g;
+				response[off + 7] = states[i].from_b;
+				response[off + 8] = states[i].on_ms;
+				response[off + 9] = states[i].off_ms;
+				response[off + 10] = states[i].count;
+				response[off + 11] = states[i].speed_ms;
 			}
 			if (!send_all(client, response, sizeof(response)))
 				dim_listener_log.error("Failed to send GET_LED response");

rpcs3/Emu/Io/DimensionsListener.h

@@ -1,12 +1,16 @@
 #pragma once
 
 // TCP listener that lets external companion apps (e.g. LegoToypad) drive the
-// emulated LEGO Dimensions Toypad, wire-compatible with harrysof's
-// Cemu-2.6-Remote-Toypad-Build listener:
+// emulated LEGO Dimensions Toypad, wire-compatible with the Cemu and shadPS4
+// listeners (LED protocol version 2):
 //
 //   LOAD:   0x01 pad index 0x00 0x00 + 180 tag bytes + u16le path length + path
 //   REMOVE: 0x02 pad index 0x00 0x00
 //   MOVE:   0x03 destPad destIndex srcPad srcIndex
+//   GET_LED:0x04 0x00 0x00 0x00 0x00 -> 40-byte LED snapshot:
+//           { 'L', serial, version(2), region count(3), then 3 regions x 12
+//             bytes: pad, mode, r, g, b, from_r, from_g, from_b, on_ms, off_ms,
+//             count, speed_ms }
 //
 // pad: 1 = center, 2 = left, 3 = right; index: 0..6.
 // Listens on 127.0.0.1:9191 (override with env RPCS3_TOYPAD_PORT).