Switch activation mask to fast interval on bridge destruction

After a bridge is hit, set ActivationMask to ActivationIntervalFast (15)
so newly spawned objects activate within 16 frames instead of 32. The
mask is reset to normal by ResetPerLife when the life ends.

Author: morozov

pkg/domain/constants.go

@@ -16,7 +16,8 @@ const (
 
 // Timing constants.
 const (
-	ActivationIntervalNormal = 31
+	ActivationIntervalNormal = 31 // 32-frame activation interval during normal gameplay
+	ActivationIntervalFast   = 15 // 16-frame activation interval after bridge destruction
 )
 
 // Player constants.

pkg/logic/death_test.go

@@ -313,6 +313,21 @@ func TestTriggerGameOver_TwoPlayer_UsesHigherScore(t *testing.T) {
 	}
 }
 
+// TestResetPerLife_ActivationMaskReset checks that the fast activation mask set after
+// bridge destruction is reset to normal on respawn (fast interval is per-life only).
+func TestResetPerLife_ActivationMaskReset(t *testing.T) {
+	t.Parallel()
+
+	s := newDeathTestState()
+	s.Viewport.ActivationMask = domain.ActivationIntervalFast
+	ResetPerLife(s, noopTerrain)
+
+	if s.Viewport.ActivationMask != domain.ActivationIntervalNormal {
+		t.Errorf("ActivationMask = %d after ResetPerLife, want %d (ActivationIntervalNormal)",
+			s.Viewport.ActivationMask, domain.ActivationIntervalNormal)
+	}
+}
+
 func TestResetPerLife_ScorePreserved(t *testing.T) {
 	t.Parallel()
 

pkg/logic/gameplay.go

@@ -97,6 +97,7 @@ func step(s *state.GameState, in input.Interface, terrain TerrainRenderer) {
 	}
 	if collision.BridgeHit {
 		s.BridgeDestroyed = true
+		s.Viewport.ActivationMask = domain.ActivationIntervalFast
 		s.Players[s.CurrentPlayer].BridgeCounter++
 		// Re-render the bridge fragment into the terrain buffer with the destruction
 		// gap so the visual change is immediate. The fragment was last rendered without

pkg/logic/gameplay_test.go

@@ -18,6 +18,36 @@ func newScrollInTestState() *state.GameState {
 	return s
 }
 
+// TestStep_BridgeHit_SetsActivationFast verifies that hitting a bridge raises the
+// activation mask to ActivationIntervalFast for the remainder of the life.
+func TestStep_BridgeHit_SetsActivationFast(t *testing.T) {
+	t.Parallel()
+
+	s := state.NewGameState()
+	s.GameplayMode = domain.GameplayNormal
+	s.InputInterface = input.InterfaceFor(0)
+	s.PlaneX = domain.PlaneStartX
+	s.Missile = &state.PlayerMissile{}
+	s.TankShell = &state.TankShell{}
+	s.HeliMissile = &state.HeliMissile{}
+	s.Viewport = state.NewViewport()
+
+	// Position the missile to hit the bridge (bridgeY=60, extent=22: missile at Y=45 overlaps).
+	const bridgeY = 60
+	s.BridgeSection = true
+	s.BridgeYPosition = bridgeY
+	s.Missile.Active = true
+	s.Missile.X = domain.PlaneStartX
+	s.Missile.Y = 45
+
+	step(s, s.InputInterface, newMockTerrainBuffer())
+
+	if s.Viewport.ActivationMask != domain.ActivationIntervalFast {
+		t.Errorf("ActivationMask = %d after bridge hit, want %d (ActivationIntervalFast)",
+			s.Viewport.ActivationMask, domain.ActivationIntervalFast)
+	}
+}
+
 // TestScrollIn_DecrementsLivesOnCompletion checks that lives are decremented
 // when the scroll-in sequence finishes.
 func TestScrollIn_DecrementsLivesOnCompletion(t *testing.T) {