Add support for bird's eye camera view

A new hotkey "hotkey.camera.togglebirdseyeview" allows to switch
between regular view and bird's eye (top-down) view.

When bird's eye view gets toggled on, the camera moves above the scene;
When bird's eye view gets toggled off, the camera moves back to the
default vertical rotation angle;
When bird's eye view is on, vertical rotation is disallowed.

binaries/data/config/default.cfg

@@ -248,6 +248,7 @@ reset = "R"                                   ; Reset camera rotation to default
 follow = ""                                   ; Follow the first unit in the selection
 rallypointfocus = ""                          ; Focus the camera on the rally point of the selected building
 lastattackfocus = "Space"                     ; Focus the camera on the last notified attack
+togglebirdseyeview = ""                       ; Toggle bird's eye view
 zoom.in = Plus, NumPlus                       ; Zoom camera in (continuous control)
 zoom.out = Minus, NumMinus                    ; Zoom camera out (continuous control)
 zoom.wheel.in = WheelUp                       ; Zoom camera in (stepped control)

binaries/data/mods/public/gui/credits/texts/programming.json

@@ -194,6 +194,7 @@
 				{ "nick": "mattlott", "name": "Matt Lott" },
 				{ "nick": "maveric", "name": "Anton Protko" },
 				{ "nick": "mbusy", "name": "Maxime Busy" },
+				{ "nick": "Mentula" },
 				{ "nick": "Micnasty", "name": "Travis Gorkin" },
 				{ "name": "Mikołaj \"Bajter\" Korcz" },
 				{ "nick": "mimo" },

binaries/data/mods/public/gui/hotkeys/spec/camera.json

@@ -23,6 +23,10 @@
 				"name": "Focus on last attack notification",
 				"desc": "Focus the camera on the position of the last attack notification."
 			},
+			"camera.togglebirdseyeview": {
+				"name": "Toggle bird's eye view",
+				"desc": "Toggle between regular and bird's eye (top-down) views."
+			},
 			"camera.zoom.in": {
 				"name": "Zoom in",
 				"desc": "Zoom camera in."

source/graphics/CameraController.cpp

@@ -54,6 +54,7 @@ CCameraController::CCameraController(CCamera& camera)
 	  m_ConstrainCamera(true),
 	  m_FollowEntity(INVALID_ENTITY),
 	  m_FollowFirstPerson(false),
+	  m_BirdsEyeView(false),
 
 	  // Dummy values (these will be filled in by the config file)
 	  m_ViewScrollSpeed(0),
@@ -179,9 +180,9 @@ void CCameraController::Update(const float deltaRealTime)
 		m_RotateY.AddSmoothly(m_ViewRotateYSpeed * deltaRealTime);
 	if (HotkeyIsPressed("camera.rotate.ccw"))
 		m_RotateY.AddSmoothly(-m_ViewRotateYSpeed * deltaRealTime);
-	if (HotkeyIsPressed("camera.rotate.up"))
+	if (HotkeyIsPressed("camera.rotate.up") && !m_BirdsEyeView)
 		m_RotateX.AddSmoothly(-m_ViewRotateXSpeed * deltaRealTime);
-	if (HotkeyIsPressed("camera.rotate.down"))
+	if (HotkeyIsPressed("camera.rotate.down") && !m_BirdsEyeView)
 		m_RotateX.AddSmoothly(m_ViewRotateXSpeed * deltaRealTime);
 
 	float moveRightward = 0.f;
@@ -297,7 +298,12 @@ void CCameraController::Update(const float deltaRealTime)
 	}
 
 	if (m_ConstrainCamera)
-		m_RotateX.ClampSmoothly(DEGTORAD(m_ViewRotateXMin), DEGTORAD(m_ViewRotateXMax));
+	{
+		if (m_BirdsEyeView)
+			m_RotateX.ClampSmoothly(M_PI / 2, M_PI / 2);
+		else
+			m_RotateX.ClampSmoothly(DEGTORAD(m_ViewRotateXMin), DEGTORAD(m_ViewRotateXMax));
+	}
 
 	FocusHeight(true);
 
@@ -462,6 +468,9 @@ void CCameraController::SetCamera(const CVector3D& pos, float rotX, float rotY,
 
 	// Break out of following mode so the camera really moves to the target
 	m_FollowEntity = INVALID_ENTITY;
+
+	// Leave bird's eye view
+	m_BirdsEyeView = false;
 }
 
 void CCameraController::MoveCameraTarget(const CVector3D& target)
@@ -508,6 +517,9 @@ void CCameraController::ResetCameraTarget(const CVector3D& target)
 
 	// Break out of following mode so the camera really moves to the target
 	m_FollowEntity = INVALID_ENTITY;
+
+	// Leave bird's eye view
+	m_BirdsEyeView = false;
 }
 
 void CCameraController::FollowEntity(entity_id_t entity, bool firstPerson)
@@ -542,6 +554,16 @@ void CCameraController::ResetCameraAngleZoom()
 	// Reset orientations to default
 	m_RotateX.SetValueSmoothly(DEGTORAD(m_ViewRotateXDefault));
 	m_RotateY.SetValueSmoothly(DEGTORAD(m_ViewRotateYDefault));
+
+	// Leave bird's eye view
+	m_BirdsEyeView = false;
+}
+
+void CCameraController::ToggleBirdsEyeView()
+{
+	m_BirdsEyeView = !m_BirdsEyeView;
+	float angle = m_BirdsEyeView ? M_PI / 2 : DEGTORAD(m_ViewRotateXDefault);
+	m_RotateX.SetValueSmoothly(angle);
 }
 
 void CCameraController::SetupCameraMatrixSmooth(CMatrix3D* orientation)
@@ -640,6 +662,11 @@ InReaction CCameraController::HandleEvent(const SDL_Event_* ev)
 			ResetCameraAngleZoom();
 			return IN_HANDLED;
 		}
+		else if (hotkey == "camera.togglebirdseyeview")
+		{
+			ToggleBirdsEyeView();
+			return IN_HANDLED;
+		}
 		return IN_PASS;
 	}
 

source/graphics/CameraController.h

@@ -60,6 +60,7 @@ public:
 private:
 	CVector3D GetSmoothPivot(CCamera &camera) const;
 	void ResetCameraAngleZoom();
+	void ToggleBirdsEyeView();
 	void SetupCameraMatrixSmooth(CMatrix3D* orientation);
 	void SetupCameraMatrixSmoothRot(CMatrix3D* orientation);
 	void SetupCameraMatrixNonSmooth(CMatrix3D* orientation);
@@ -86,6 +87,11 @@ private:
 	*/
 	bool m_FollowFirstPerson;
 
+	/**
+	* Whether the camera is in bird's eye view mode.
+	*/
+	bool m_BirdsEyeView;
+
 	// Settings
 	float m_ViewScrollSpeed;
 	float m_ViewScrollSpeedModifier;