From 85c297a28b54d53462c13285ce879cd6e43ce8d5 Mon Sep 17 00:00:00 2001
From: chenzw <[EMAIL REDACTED]>
Date: Tue, 10 Feb 2026 15:51:35 +0800
Subject: [PATCH] Added IMU support for GameSir controllers with optimized
sampling rate and timestamp synchronization.
---
src/joystick/hidapi/SDL_hidapi_gamesir.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/joystick/hidapi/SDL_hidapi_gamesir.c b/src/joystick/hidapi/SDL_hidapi_gamesir.c
index cfb92bea9b58f..1a1bf9525ab12 100644
--- a/src/joystick/hidapi/SDL_hidapi_gamesir.c
+++ b/src/joystick/hidapi/SDL_hidapi_gamesir.c
@@ -35,6 +35,7 @@
#define GAMESIR_PACKET_HEADER_0 0xA1
#define GAMESIR_PACKET_HEADER_1_GAMEPAD 0xC8
+#define GAMESIR_IMU_RATE_HZ 1000
#define BTN_A 0x01
#define BTN_B 0x02
@@ -335,6 +336,7 @@ static bool HIDAPI_DriverGameSir_InitDevice(SDL_HIDAPI_Device *device)
ctx->led_supported = true;
ctx->output_handle = GetOutputHandle(device);
+ ctx->sensor_timestamp_step_ns = SDL_NS_PER_SECOND / GAMESIR_IMU_RATE_HZ;
switch (device->product_id) {
case USB_PRODUCT_GAMESIR_GAMEPAD_G7_PRO_8K:
@@ -385,7 +387,9 @@ static bool HIDAPI_DriverGameSir_OpenJoystick(SDL_HIDAPI_Device *device, SDL_Joy
joystick->nhats = 1;
if (ctx->sensors_supported) {
- ctx->sensor_timestamp_step_ns = SDL_NS_PER_SECOND / 125;
+ // GameSir SDL protocol packets currently don't expose an IMU timestamp.
+ // Use a synthetic monotonic timestamp at the firmware's fixed IMU rate.
+ ctx->sensor_timestamp_ns = SDL_GetTicksNS();
// Accelerometer scale factor: assume a range of ±2g, 16-bit signed values (-32768 to 32767)
// 32768 corresponds to 2g, so the scale factor = 2 * SDL_STANDARD_GRAVITY / 32768.0f
ctx->accelScale = 2.0f * SDL_STANDARD_GRAVITY / 32768.0f;
@@ -398,7 +402,7 @@ static bool HIDAPI_DriverGameSir_OpenJoystick(SDL_HIDAPI_Device *device, SDL_Joy
const float gyro_denominator = 16.0f;
ctx->gyroScale = (gyro_numerator / gyro_denominator) * (SDL_PI_F / 180.0f);
- const float flSensorRate = 1000.0f;
+ const float flSensorRate = (float)GAMESIR_IMU_RATE_HZ;
SDL_PrivateJoystickAddSensor(joystick, SDL_SENSOR_GYRO, flSensorRate);
SDL_PrivateJoystickAddSensor(joystick, SDL_SENSOR_ACCEL, flSensorRate);
}
@@ -485,6 +489,9 @@ static bool HIDAPI_DriverGameSir_SetJoystickSensorsEnabled(SDL_HIDAPI_Device *de
SDL_DriverGamesir_Context *ctx = (SDL_DriverGamesir_Context *)device->context;
if (ctx->sensors_supported) {
ctx->sensors_enabled = enabled;
+ if (enabled) {
+ ctx->sensor_timestamp_ns = SDL_GetTicksNS();
+ }
return true;
}
return SDL_Unsupported();