add basic camera controls

include/td/render/Camera.h

@@ -35,6 +35,7 @@ class Camera {
 	void UpdatePerspective(float a_AspectRatio);
 
 	void SetCamPos(const Vec3f& a_NewPos);
+	const Vec3f& GetCamPos() const;
 };
 
 }  // namespace render

include/td/render/renderer/WorldRenderer.h

@@ -17,6 +17,9 @@ class WorldRenderer : public Renderer<shader::WorldShader> {
 	virtual ~WorldRenderer();
 
 	virtual void Render(float a_Lerp) override;
+
+  private:
+	void UpdateControls();
 };
 
 }  // namespace render