From 2bb0eb46413a381f3ff8d40311b166c69fe7fa9e Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Sun, 2 Nov 2025 08:23:18 -0800
Subject: [PATCH] Fixed the right touchpad calculation for the BLE Steam
 Controller

Fixes https://github.com/libsdl-org/SDL/issues/14368

(cherry picked from commit eb87a36940f34a8ea4eb73061b84f9b94b3d3b03)
---
 src/joystick/hidapi/SDL_hidapi_steam.c | 34 ++++++++++++++------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/joystick/hidapi/SDL_hidapi_steam.c b/src/joystick/hidapi/SDL_hidapi_steam.c
index 9a712b0d82..b29589ff03 100644
--- a/src/joystick/hidapi/SDL_hidapi_steam.c
+++ b/src/joystick/hidapi/SDL_hidapi_steam.c
@@ -644,13 +644,6 @@ static void RotatePad(int *pX, int *pY, float flAngleInRad)
     *pX = (int)(SDL_cosf(flAngleInRad) * origX - SDL_sinf(flAngleInRad) * origY);
     *pY = (int)(SDL_sinf(flAngleInRad) * origX + SDL_cosf(flAngleInRad) * origY);
 }
-static void RotatePadShort(short *pX, short *pY, float flAngleInRad)
-{
-    short int origX = *pX, origY = *pY;
-
-    *pX = (short)(SDL_cosf(flAngleInRad) * origX - SDL_sinf(flAngleInRad) * origY);
-    *pY = (short)(SDL_sinf(flAngleInRad) * origX + SDL_cosf(flAngleInRad) * origY);
-}
 
 //---------------------------------------------------------------------------
 // Format the first part of the state packet
@@ -774,9 +767,16 @@ static void FormatStatePacketUntilGyro(SteamControllerStateInternal_t *pState, V
 //---------------------------------------------------------------------------
 static bool UpdateBLESteamControllerState(const uint8_t *pData, int nDataSize, SteamControllerStateInternal_t *pState)
 {
-    const float flRotationAngle = 0.261799f;
+    int nLeftPadX;
+    int nLeftPadY;
+    int nRightPadX;
+    int nRightPadY;
+    int nPadOffset;
     uint32_t ucOptionDataMask;
 
+    // 15 degrees in rad
+    const float flRotationAngle = 0.261799f;
+
     pState->unPacketNum++;
     ucOptionDataMask = (*pData++ & 0xF0);
     ucOptionDataMask |= (uint32_t)(*pData++) << 8;
@@ -805,7 +805,6 @@ static bool UpdateBLESteamControllerState(const uint8_t *pData, int nDataSize, S
     }
     if (ucOptionDataMask & k_EBLELeftTrackpadChunk) {
         int nLength = sizeof(pState->sLeftPadX) + sizeof(pState->sLeftPadY);
-        int nPadOffset;
         SDL_memcpy(&pState->sLeftPadX, pData, nLength);
         if (pState->ulButtons & STEAM_LEFTPAD_FINGERDOWN_MASK) {
             nPadOffset = 1000;
@@ -813,14 +812,15 @@ static bool UpdateBLESteamControllerState(const uint8_t *pData, int nDataSize, S
             nPadOffset = 0;
         }
 
-        RotatePadShort(&pState->sLeftPadX, &pState->sLeftPadY, -flRotationAngle);
-        pState->sLeftPadX = clamp(pState->sLeftPadX + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
-        pState->sLeftPadY = clamp(pState->sLeftPadY + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
+        nLeftPadX = pState->sLeftPadX;
+        nLeftPadY = pState->sLeftPadY;
+        RotatePad(&nLeftPadX, &nLeftPadY, -flRotationAngle);
+        pState->sLeftPadX = (short)clamp(nLeftPadX + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
+        pState->sLeftPadY = (short)clamp(nLeftPadY + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
         pData += nLength;
     }
     if (ucOptionDataMask & k_EBLERightTrackpadChunk) {
         int nLength = sizeof(pState->sRightPadX) + sizeof(pState->sRightPadY);
-        int nPadOffset = 0;
 
         SDL_memcpy(&pState->sRightPadX, pData, nLength);
 
@@ -830,9 +830,11 @@ static bool UpdateBLESteamControllerState(const uint8_t *pData, int nDataSize, S
             nPadOffset = 0;
         }
 
-        RotatePadShort(&pState->sRightPadX, &pState->sRightPadY, flRotationAngle);
-        pState->sRightPadX = clamp(pState->sRightPadX + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
-        pState->sRightPadY = clamp(pState->sRightPadY + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
+        nRightPadX = pState->sRightPadX;
+        nRightPadY = pState->sRightPadY;
+        RotatePad(&nRightPadX, &nRightPadY, flRotationAngle);
+        pState->sRightPadX = (short)clamp(nRightPadX + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
+        pState->sRightPadY = (short)clamp(nRightPadY + nPadOffset, SDL_MIN_SINT16, SDL_MAX_SINT16);
         pData += nLength;
     }
     if (ucOptionDataMask & k_EBLEIMUAccelChunk) {