fix(input): map middle click to MouseButton3 (#171)

include/runtime/roblox_input_router.h

@@ -40,9 +40,10 @@ struct AndroidKeyMapping {
 // through with an ABI-incompatible numeric value.
 AndroidKeyMapping MapSdlKeyToAndroid(uint32_t sdl_scancode, uint32_t sdl_key = 0);
 
-// Mirrors the APK's MotionEvent.getActionButton() - 1 conversion. SDL button
-// numbers are not numerically compatible with Android button bit values.
-int32_t MapSdlMouseButtonToAndroid(uint8_t sdl_button);
+// Translates SDL button numbers to the nativePassMouseButton argument.
+// The first three are Roblox's zero-based MouseButton1/2/3 indices, not Android
+// MotionEvent button bits.
+int32_t MapSdlMouseButtonToRoblox(uint8_t sdl_button);
 
 int32_t MapSdlGamepadButtonToAndroid(uint8_t sdl_button);
 int32_t RobloxGamepadType(platform::GamepadFamily family);

src/runtime/roblox_input_router.cc

@@ -274,14 +274,15 @@ AndroidKeyMapping MapSdlKeyToAndroid(uint32_t sdl_scancode,
   return {};
 }
 
-int32_t MapSdlMouseButtonToAndroid(uint8_t sdl_button) {
+int32_t MapSdlMouseButtonToRoblox(uint8_t sdl_button) {
   switch (sdl_button) {
     case SDL_BUTTON_LEFT:
       return 0;
     case SDL_BUTTON_RIGHT:
       return 1;
     case SDL_BUTTON_MIDDLE:
-      return 3;
+      // MouseButton3 is index 2, not BUTTON_TERTIARY (4) minus one.
+      return 2;
     case SDL_BUTTON_X1:
       return 7;
     case SDL_BUTTON_X2:
@@ -569,11 +570,11 @@ RobloxInputDispatchResult RobloxInputRouter::HandleMouseButtonLocked(
                   RobloxInputEventKind::kMouseButton,
                   Unsupported("native mouse buttons are unavailable"));
   }
-  const int32_t android_button = MapSdlMouseButtonToAndroid(event.button);
-  if (android_button < 0) {
+  const int32_t roblox_button = MapSdlMouseButtonToRoblox(event.button);
+  if (roblox_button < 0) {
     return Result(RobloxInputDispatchState::kIgnoredUnsupported,
                   RobloxInputEventKind::kMouseButton,
-                  Unsupported("SDL mouse button has no Android mapping"));
+                  Unsupported("SDL mouse button has no Roblox mapping"));
   }
   if (event.x > 0.0f || event.y > 0.0f ||
       (mouse_x_ == 0.0f && mouse_y_ == 0.0f)) {
@@ -596,12 +597,12 @@ RobloxInputDispatchResult RobloxInputRouter::HandleMouseButtonLocked(
     }
   }
   Status status = sink_.mouse_button(sink_.context, clamped_x, clamped_y,
-                                     event.pressed, android_button);
+                                     event.pressed, roblox_button);
   if (status.ok()) {
     const auto active = std::find(active_mouse_buttons_.begin(),
-                                  active_mouse_buttons_.end(), android_button);
+                                  active_mouse_buttons_.end(), roblox_button);
     if (event.pressed && active == active_mouse_buttons_.end()) {
-      active_mouse_buttons_.push_back(android_button);
+      active_mouse_buttons_.push_back(roblox_button);
     } else if (!event.pressed && active != active_mouse_buttons_.end()) {
       active_mouse_buttons_.erase(active);
     }

tests/roblox_input_native_adapter_test.cc

@@ -325,7 +325,7 @@ TEST_F(RobloxInputNativeAdapterTest, CallsExactExportedJniSignatures) {
             (std::vector<double>{90.0, 190.0, 4.0, -2.0}));
   EXPECT_EQ(probe_.calls[1].name, "mouse-button");
   EXPECT_EQ(probe_.calls[1].arguments,
-            (std::vector<double>{100.0, 200.0, JNI_TRUE, 3.0}));
+            (std::vector<double>{100.0, 200.0, JNI_TRUE, 2.0}));
   EXPECT_EQ(probe_.calls[2].name, "touch");
   EXPECT_EQ(probe_.calls[2].arguments,
             (std::vector<double>{0.0, 320.0, 360.0, 0.0, 1280.0, 720.0}));

tests/roblox_input_router_test.cc

@@ -170,13 +170,13 @@ class RobloxInputRouterTest : public ::testing::Test {
   RobloxInputRouter router_{Sink(&probe_)};
 };
 
-TEST(RobloxInputMappingTest, MapsAndroidMouseButtonsExactlyLikeApk) {
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(SDL_BUTTON_LEFT), 0);
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(SDL_BUTTON_RIGHT), 1);
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(SDL_BUTTON_MIDDLE), 3);
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(SDL_BUTTON_X1), 7);
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(SDL_BUTTON_X2), 15);
-  EXPECT_EQ(MapSdlMouseButtonToAndroid(42), -1);
+TEST(RobloxInputMappingTest, MapsMouseButtonsForNativeInput) {
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(SDL_BUTTON_LEFT), 0);
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(SDL_BUTTON_RIGHT), 1);
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(SDL_BUTTON_MIDDLE), 2);
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(SDL_BUTTON_X1), 7);
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(SDL_BUTTON_X2), 15);
+  EXPECT_EQ(MapSdlMouseButtonToRoblox(42), -1);
 }
 
 TEST(RobloxInputMappingTest, MapsSdlUsbKeysToLinuxAndAndroidCodes) {
@@ -238,6 +238,25 @@ TEST_F(RobloxInputRouterTest, RoutesMouseMotionButtonAndVerticalWheel) {
   EXPECT_FLOAT_EQ(probe_.mouse_wheels[0].delta_y, -2.0f);
 }
 
+TEST_F(RobloxInputRouterTest, MiddleClickUsesMouseButton3OnPressAndRelease) {
+  ASSERT_TRUE(router_
+                  .HandleEvent(Event(platform::MouseButtonEvent{
+                      true, SDL_BUTTON_MIDDLE, 1, 100.0f, 80.0f}))
+                  .dispatched());
+  EXPECT_EQ(router_.Snapshot().active_mouse_buttons, 1U);
+  ASSERT_TRUE(router_
+                  .HandleEvent(Event(platform::MouseButtonEvent{
+                      false, SDL_BUTTON_MIDDLE, 1, 100.0f, 80.0f}))
+                  .dispatched());
+
+  ASSERT_EQ(probe_.mouse_buttons.size(), 2U);
+  EXPECT_TRUE(probe_.mouse_buttons[0].pressed);
+  EXPECT_EQ(probe_.mouse_buttons[0].button, 2);
+  EXPECT_FALSE(probe_.mouse_buttons[1].pressed);
+  EXPECT_EQ(probe_.mouse_buttons[1].button, 2);
+  EXPECT_EQ(router_.Snapshot().active_mouse_buttons, 0U);
+}
+
 TEST_F(RobloxInputRouterTest,
        ScalesMouseCoordinatesAfterDisplayScaleChange) {
   const RobloxInputDispatchResult resize = router_.HandleEvent(