SDL3 Add DSU joystick driver

Introduces DSU client joystick support for SDL, enabling connection to DSU servers (such as DS4Windows and BetterJoy) to receive controller data over UDP, including motion sensors and touchpad data. Adds build system options, configuration hints, protocol implementation, and driver integration for Windows and other platforms.

Author: danprice142

CMakeLists.txt

@@ -380,6 +380,7 @@ dep_option(SDL_HIDAPI_LIBUSB       "Use libusb for low level joystick drivers" O
 dep_option(SDL_HIDAPI_LIBUSB_SHARED "Dynamically load libusb support" ON "SDL_HIDAPI_LIBUSB;SDL_DEPS_SHARED" OFF)
 dep_option(SDL_HIDAPI_JOYSTICK     "Use HIDAPI for low level joystick drivers" ON SDL_HIDAPI OFF)
 dep_option(SDL_VIRTUAL_JOYSTICK    "Enable the virtual-joystick driver" ON SDL_HIDAPI OFF)
+option(SDL_DSU_JOYSTICK             "Enable DSU client joystick support" ON)
 set_option(SDL_LIBUDEV             "Enable libudev support" ON)
 set_option(SDL_ASAN                "Use AddressSanitizer to detect memory errors" OFF)
 set_option(SDL_CCACHE              "Use Ccache to speed up build" OFF)
@@ -1374,6 +1375,24 @@ if(SDL_JOYSTICK)
       "${SDL3_SOURCE_DIR}/src/joystick/virtual/*.h"
     )
   endif()
+  
+  # DSU (DualShock UDP) client support
+  if(SDL_DSU_JOYSTICK)
+    set(SDL_JOYSTICK_DSU 1)
+    sdl_glob_sources(
+      "${SDL3_SOURCE_DIR}/src/joystick/dsu/*.c"
+      "${SDL3_SOURCE_DIR}/src/joystick/dsu/*.h"
+    )
+    
+    # DSU requires network libraries
+    if(WIN32)
+      list(APPEND SDL3_EXTRA_LIBS ws2_32)
+    elseif(UNIX AND NOT APPLE AND NOT ANDROID AND NOT HAIKU)
+      # Unix systems typically have sockets built-in
+    elseif(HAIKU)
+      list(APPEND SDL3_EXTRA_LIBS network)
+    endif()
+  endif()
 endif()
 
 if(SDL_VIDEO)

include/SDL3/SDL_hints.h

@@ -2319,6 +2319,56 @@ extern "C" {
  */
 #define SDL_HINT_JOYSTICK_WGI "SDL_JOYSTICK_WGI"
 
+/**
+ * A variable controlling whether the DSU (DualShock UDP) joystick driver should be used.
+ *
+ * This variable can be set to the following values:
+ *
+ * - "0": DSU driver is disabled
+ * - "1": DSU driver is enabled (default)
+ *
+ * The DSU driver allows SDL to connect to DSU servers (DS4Windows, BetterJoy, etc.)
+ * to receive controller data over UDP, including motion sensors and touchpad data.
+ *
+ * This hint should be set before SDL is initialized.
+ *
+ * \since This hint is available since SDL 3.2.0.
+ */
+#define SDL_HINT_JOYSTICK_DSU "SDL_JOYSTICK_DSU"
+
+/**
+ * A variable controlling the DSU server address.
+ *
+ * The default value is "127.0.0.1"
+ *
+ * This hint should be set before SDL is initialized.
+ *
+ * \since This hint is available since SDL 3.2.0.
+ */
+#define SDL_HINT_DSU_SERVER "SDL_DSU_SERVER"
+
+/**
+ * A variable controlling the DSU server port.
+ *
+ * The default value is "26760"
+ *
+ * This hint should be set before SDL is initialized.
+ *
+ * \since This hint is available since SDL 3.2.0.
+ */
+#define SDL_HINT_DSU_SERVER_PORT "SDL_DSU_SERVER_PORT"
+
+/**
+ * A variable controlling the DSU client port.
+ *
+ * The default value is "0" (auto-select)
+ *
+ * This hint should be set before SDL is initialized.
+ *
+ * \since This hint is available since SDL 3.2.0.
+ */
+#define SDL_HINT_DSU_CLIENT_PORT "SDL_DSU_CLIENT_PORT"
+
 /**
  * A variable containing a list of wheel style controllers.
  *

include/build_config/SDL_build_config.h.cmake

@@ -313,6 +313,7 @@
 #cmakedefine SDL_JOYSTICK_RAWINPUT 1
 #cmakedefine SDL_JOYSTICK_USBHID 1
 #cmakedefine SDL_JOYSTICK_VIRTUAL 1
+#cmakedefine SDL_JOYSTICK_DSU 1
 #cmakedefine SDL_JOYSTICK_VITA 1
 #cmakedefine SDL_JOYSTICK_WGI 1
 #cmakedefine SDL_JOYSTICK_XINPUT 1

include/build_config/SDL_build_config_windows.h

@@ -231,6 +231,7 @@ typedef unsigned int uintptr_t;
 #define SDL_JOYSTICK_HIDAPI 1
 #define SDL_JOYSTICK_RAWINPUT 1
 #define SDL_JOYSTICK_VIRTUAL 1
+#define SDL_JOYSTICK_DSU 1
 #ifdef HAVE_WINDOWS_GAMING_INPUT_H
 #define SDL_JOYSTICK_WGI 1
 #endif

src/joystick/SDL_joystick.c

@@ -48,6 +48,10 @@
 #include "./virtual/SDL_virtualjoystick_c.h"
 #endif
 
+#ifdef SDL_JOYSTICK_DSU
+#include "./dsu/SDL_dsujoystick_c.h"
+#endif
+
 static SDL_JoystickDriver *SDL_joystick_drivers[] = {
 #ifdef SDL_JOYSTICK_HIDAPI // Highest priority driver for supported devices
     &SDL_HIDAPI_JoystickDriver,
@@ -100,6 +104,9 @@ static SDL_JoystickDriver *SDL_joystick_drivers[] = {
 #ifdef SDL_JOYSTICK_VIRTUAL
     &SDL_VIRTUAL_JoystickDriver,
 #endif
+#ifdef SDL_JOYSTICK_DSU
+    &SDL_DSU_JoystickDriver,
+#endif
 #ifdef SDL_JOYSTICK_VITA
     &SDL_VITA_JoystickDriver,
 #endif

src/joystick/SDL_sysjoystick.h

@@ -255,6 +255,7 @@ extern SDL_JoystickDriver SDL_RAWINPUT_JoystickDriver;
 extern SDL_JoystickDriver SDL_IOS_JoystickDriver;
 extern SDL_JoystickDriver SDL_LINUX_JoystickDriver;
 extern SDL_JoystickDriver SDL_VIRTUAL_JoystickDriver;
+extern SDL_JoystickDriver SDL_DSU_JoystickDriver;
 extern SDL_JoystickDriver SDL_WGI_JoystickDriver;
 extern SDL_JoystickDriver SDL_WINDOWS_JoystickDriver;
 extern SDL_JoystickDriver SDL_WINMM_JoystickDriver;