Fixed SDL_GetNumGamepadTouchpads() returning 1 for a NULL gamepad

src/joystick/SDL_gamepad.c

@@ -3054,7 +3054,7 @@ SDL_GamepadButtonLabel SDL_GetGamepadButtonLabel(SDL_Gamepad *gamepad, SDL_Gamep
  */
 int SDL_GetNumGamepadTouchpads(SDL_Gamepad *gamepad)
 {
-    int result = true;
+    int result = 0;
 
     SDL_LockJoysticks();
     {
@@ -3073,7 +3073,7 @@ int SDL_GetNumGamepadTouchpads(SDL_Gamepad *gamepad)
  */
 int SDL_GetNumGamepadTouchpadFingers(SDL_Gamepad *gamepad, int touchpad)
 {
-    int result = true;
+    int result = 0;
 
     SDL_LockJoysticks();
     {
@@ -3081,8 +3081,6 @@ int SDL_GetNumGamepadTouchpadFingers(SDL_Gamepad *gamepad, int touchpad)
         if (joystick) {
             if (touchpad >= 0 && touchpad < joystick->ntouchpads) {
                 result = joystick->touchpads[touchpad].nfingers;
-            } else {
-                result = SDL_InvalidParamError("touchpad");
             }
         }
     }
@@ -3326,7 +3324,7 @@ SDL_JoystickID SDL_GetGamepadID(SDL_Gamepad *gamepad)
 
 SDL_PropertiesID SDL_GetGamepadProperties(SDL_Gamepad *gamepad)
 {
-    SDL_PropertiesID result = true;
+    SDL_PropertiesID result = 0;
 
     SDL_LockJoysticks();
     {