From 2bb0eb46413a381f3ff8d40311b166c69fe7fa9e Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
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 9a712b0d82d86..b29589ff031e6 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) {