Use the triggers to test rumble for more fine grained vibration feedback

test/testgamecontroller.c

@@ -114,11 +114,6 @@ loop(void *arg)
         case SDL_CONTROLLERBUTTONDOWN:
         case SDL_CONTROLLERBUTTONUP:
             SDL_Log("Controller button %s %s\n", SDL_GameControllerGetStringForButton((SDL_GameControllerButton)event.cbutton.button), event.cbutton.state ? "pressed" : "released");
-            /* First button triggers a 0.5 second full strength rumble */
-            if (event.type == SDL_CONTROLLERBUTTONDOWN &&
-                event.cbutton.button == SDL_CONTROLLER_BUTTON_A) {
-                SDL_GameControllerRumble(gamecontroller, 0xFFFF, 0xFFFF, 500);
-            }
             break;
         case SDL_KEYDOWN:
             if (event.key.keysym.sym != SDLK_ESCAPE) {
@@ -155,6 +150,13 @@ loop(void *arg)
         }
     }
 
+    /* Update rumble based on trigger state */
+    {
+        Uint16 low_frequency_rumble = SDL_GameControllerGetAxis(gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERLEFT) * 2;
+        Uint16 high_frequency_rumble = SDL_GameControllerGetAxis(gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERRIGHT) * 2;
+        SDL_GameControllerRumble(gamecontroller, low_frequency_rumble, high_frequency_rumble, 250);
+    }
+
     SDL_RenderPresent(screen);
 
     if (!SDL_GameControllerGetAttached(gamecontroller)) {