[Feat]: Mouse zoom with scroll

cppvolrend/app_freeglut.cpp

@@ -62,6 +62,8 @@ void ApplicationFreeGLUT::s_OnMotion (int x, int y)
 
 void ApplicationFreeGLUT::s_MouseWheel (int wheel, int direction, int x, int y)
 {
+  RenderingManager::Instance()->MouseWheel(wheel, direction, x, y);
+
   // ImGui callback
   ImGui_ImplGLUT_MouseWheelFunc(wheel, direction, x, y);
 }

cppvolrend/renderingmanager.cpp

@@ -369,6 +369,13 @@ void RenderingManager::MouseMotion (int x, int y)
   PostRedisplay();
 }
 
+void RenderingManager::MouseWheel(int wheel, int direction, int x, int y)
+{
+  curr_rdr_parameters.GetCamera()->MouseWheel(wheel, direction, x, y);
+
+  PostRedisplay();
+}
+
 void RenderingManager::CloseFunc ()
 {
   gl::PipelineShader::Unbind();

cppvolrend/renderingmanager.h

@@ -60,6 +60,8 @@ class RenderingManager
   void KeyboardUp (unsigned char key, int x, int y);
   void MouseButton (int bt, int st, int x, int y);
   void MouseMotion (int x, int y);
+  void MouseWheel(int wheel, int direction, int x, int y);
+
   void CloseFunc ();
   void IdleFunc ();
   void PostRedisplay ();

libs/vis_utils/camera.cpp

@@ -81,6 +81,7 @@ namespace vis
     radius = 50;
     speed = 0.001f;
     speed_radius = 1.0f;
+    speed_zoom = 50.0f;
 
     min_radius = 0;
     max_radius = 1000;
@@ -104,7 +105,8 @@ namespace vis
     radius = _radius;
     speed = 0.001f;
     speed_radius = 1.0f;
-
+    speed_zoom = 50.0f;
+
     min_radius = _min_rad;
     max_radius = _max_rad;
 
@@ -236,6 +238,25 @@ namespace vis
     return 0;
   }
 
+  int Camera::MouseWheel(int wheel, int direction, int x, int y)
+  {
+	  if (wheel == 0) {
+		  radius += -direction * speed_zoom;
+		  if (radius < min_radius)
+			  radius = min_radius;
+		  if (radius > max_radius)
+			  radius = max_radius;
+
+		  glm::vec3 c_e = glm::normalize(glm::vec3(c_data.eye - c_data.center));
+
+		  c_data.eye = c_e * radius;
+
+		  m_changing_camera = true;
+          return 1;
+	  }
+	  return 0;
+  }
+
   float Camera::GetSpeedKeyboardMovement ()
   {
     return speed_keyboard_movement;

libs/vis_utils/camera.h

@@ -104,6 +104,7 @@ namespace vis
     bool KeyboardUp (unsigned char key, int x, int y);
     int MouseButton (int bt, int st, int x, int y);
     int MouseMotion (int x, int y);
+	int MouseWheel(int wheel, int direction, int x, int y);
 
     float GetSpeedKeyboardMovement ();
     void SetSpeedKeyboardMovement (float sskm);
@@ -165,6 +166,7 @@ namespace vis
     float radius;
     float speed;
     float speed_radius;
+    float speed_zoom = 50.0f;
 
     float min_radius;
     float max_radius;