From 467434b92d0ca8f5a691e36059eb1ac673dfd6b2 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sat, 7 Mar 2020 13:17:28 -0800
Subject: [PATCH] Added support for indicating player index on DS4 controllers

---
 src/joystick/hidapi/SDL_hidapi_ps4.c | 50 +++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 5 deletions(-)

diff --git a/src/joystick/hidapi/SDL_hidapi_ps4.c b/src/joystick/hidapi/SDL_hidapi_ps4.c
index c2e590ad1988f..8288d1fb1ff7a 100644
--- a/src/joystick/hidapi/SDL_hidapi_ps4.c
+++ b/src/joystick/hidapi/SDL_hidapi_ps4.c
@@ -100,6 +100,7 @@ typedef struct {
     SDL_bool is_bluetooth;
     SDL_bool audio_supported;
     SDL_bool rumble_supported;
+    int player_index;
     Uint8 volume;
     Uint32 last_volume_check;
     PS4StatePacket_t last_state;
@@ -182,6 +183,33 @@ static SDL_bool HIDAPI_DriverPS4_CanRumble(Uint16 vendor_id, Uint16 product_id)
     return SDL_TRUE;
 }
 
+static void
+SetLedsForPlayerIndex(DS4EffectsState_t *effects, int player_index)
+{
+    /* This list is the same as what hid-sony.c uses in the Linux kernel.
+       The first 4 values correspond to what the PS4 assigns.
+    */
+    static const Uint8 colors[7][3] = {
+        { 0x00, 0x00, 0x40 }, /* Blue */
+        { 0x40, 0x00, 0x00 }, /* Red */
+        { 0x00, 0x40, 0x00 }, /* Green */
+        { 0x20, 0x00, 0x20 }, /* Pink */
+        { 0x02, 0x01, 0x00 }, /* Orange */
+        { 0x00, 0x01, 0x01 }, /* Teal */
+        { 0x01, 0x01, 0x01 }  /* White */
+    };
+
+    if (player_index >= 0) {
+        player_index %= SDL_arraysize(colors);
+    } else {
+        player_index = 0;
+    }
+
+    effects->ucLedRed = colors[player_index][0];
+    effects->ucLedGreen = colors[player_index][1];
+    effects->ucLedBlue = colors[player_index][2];
+}
+
 static SDL_bool
 HIDAPI_DriverPS4_InitDevice(SDL_HIDAPI_Device *device)
 {
@@ -194,12 +222,22 @@ HIDAPI_DriverPS4_GetDevicePlayerIndex(SDL_HIDAPI_Device *device, SDL_JoystickID
     return -1;
 }
 
+static int HIDAPI_DriverPS4_RumbleJoystick(SDL_HIDAPI_Device *device, SDL_Joystick *joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble);
+
 static void
 HIDAPI_DriverPS4_SetDevicePlayerIndex(SDL_HIDAPI_Device *device, SDL_JoystickID instance_id, int player_index)
 {
-}
+    SDL_DriverPS4_Context *ctx = (SDL_DriverPS4_Context *)device->context;
 
-static int HIDAPI_DriverPS4_RumbleJoystick(SDL_HIDAPI_Device *device, SDL_Joystick *joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble);
+    if (!ctx) {
+        return;
+    }
+
+    ctx->player_index = player_index;
+
+    /* This will set the new LED state based on the new player index */
+    HIDAPI_DriverPS4_RumbleJoystick(device, SDL_JoystickFromInstanceID(instance_id), 0, 0);
+}
 
 static SDL_bool
 HIDAPI_DriverPS4_OpenJoystick(SDL_HIDAPI_Device *device, SDL_Joystick *joystick)
@@ -248,6 +286,9 @@ HIDAPI_DriverPS4_OpenJoystick(SDL_HIDAPI_Device *device, SDL_Joystick *joystick)
         }
     }
 
+    /* Initialize player index (needed for setting LEDs) */
+    ctx->player_index = SDL_JoystickGetPlayerIndex(joystick);
+
     /* Initialize LED and effect state */
     HIDAPI_DriverPS4_RumbleJoystick(device, joystick, 0, 0);
 
@@ -293,9 +334,8 @@ HIDAPI_DriverPS4_RumbleJoystick(SDL_HIDAPI_Device *device, SDL_Joystick *joystic
     effects->ucRumbleLeft = (low_frequency_rumble >> 8);
     effects->ucRumbleRight = (high_frequency_rumble >> 8);
 
-    effects->ucLedRed = 0;
-    effects->ucLedGreen = 0;
-    effects->ucLedBlue = 80;
+    /* Populate the LED state with the appropriate color from our lookup table */
+    SetLedsForPlayerIndex(effects, ctx->player_index);
 
     if (ctx->is_bluetooth) {
         /* Bluetooth reports need a CRC at the end of the packet (at least on Linux) */