BansheeEngine/SceneView.txt

TODO:
 - Core thread gets stuck on shutdown when OpenGL is used...Somewhere in kernel

CONCRETE TASK:
 - Hook up gizmo manager to ScenePicking so gizmos are considered when picking
   - I'll likely need to update GizmoManager so I can query gizmo SceneObject based on gizmo index
 - Selection/ScenePicking/GizmoManager need to be started

IMMEDIATE:
 - SceneGrid is very ugly. Consider using default lines for now and come back with a better approach later.
   - Potentially enable line AA?
 - Picking code is completely untested and will likely need major fixing
 - Test all the new DrawHelper3D methods

 GIZMO TODO:
  - Figure out how to deal with builtin components like Camera and Renderable (e.g. how will they have gizmos since they're not managed components?)

LATER:
 - Need a way to render text for gizmos and handles, and in scene in general

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Handles

SliderLine - position, direction, length
  - When initially activated it records position nearest so the line as the starting point
  - Further mouse dragging also finds nearest position to the line
  - Difference between those two results in a float value (how much to move along direction from position to reach new position)
  - Slider line has a capsule + sphere collider size of which can be set manually

SliderPlane - position, normal, size
  - Similar to line slider only the direction is determined dynamically as well as distance
  - Outputs a Vector2 (direction * distance moved)
  - A OOB is used as a collider

SliderDisc - position, normal, radius
  - When initially activated it records position nearest so the disc as the starting point
  - Further movement calculates the dynamic direction from the starting point to the current point on the plane the disc lies on
  - Distance along that direction is returned as amount of movement (similar to line slider)
  - Outputs a single float
  - A torus is used as a collider

Free move/rotate/scale handles need to exist as well
 - Scale is easy, just perform uniform scale. Use SliderPlane oriented towards camera
 - Move also use SliderPlane oriented towards camera
 - Rotation use SliderDisc oriented towards camera

CONCRETE TODO:
HandleSliderManager
 - Detecting input and updating the sliders
 - isHandleActive

ScriptHandleManager
 - Pretty much everything (in more detail in .cpp file)
 - Needs to be started up somewhere

C# Component needs "sceneObject" property
C# SceneObject needs position/rot/scale (and local variants) properties

SceneEditorWidget
 - Need to glue everything together

More complex handles (combinations of sliders + draw methods)
 - In C#, called by ScriptHandleManager

Nearest point to disc/arc code
More complex types for drawing like DrawArrow in HandleDrawManager
Handles that remain the same size regardless of distance from camera
 - For both drawing and collision
Consider local vs. global handle mode

OPEN QUESTIONS:
 - How to handle handles with multiple selection?

EXAMPLE:

[CustomHandle(typeof(Camera))]
class CameraHandle : IHandle
{
     SliderLine xAxis;
     SliderLine yAxis;
     
     CameraHandle()
     {
         xAxis = new SliderLine(Vector3.right, 10.0f);
         yAxis = new SliderLine(Vector3.up, 10.0f);

         xAxis.onDragged += onXAxis();
         yAxis.onDragged += onYAxis();
     }

     void onXAxis()
     {
          // Here I can decide whether or not I want to use handle data or not, per object instance
          target.position = xAxis.getMove(target.position);
     }

     void onYAxis()
     {
          target.position = yAxis.getMove(target.position);
     }

     void Update()
     {
           // Resize handle, change matrix, etc.
     }

     void Draw()
     {
           xAxis.Draw();

           HandleDraw.Arrow(target.position, Vector3.right, 10.0f);
           HandleDraw.Arrow(target.position, Vector3.up, 10.0f);
     }
}

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SelectionRenderer

Retrieve a list of selected objects from SelectionManager
Find ones with Renderable components
Retrieve Meshes, and world transforms from them
Draw that same mesh with either a wireframe or a grayed out shader with a slight depth bias

----------------------------------------------------------------------
SceneView editor flow:
  Hook up gizmo, handle and selection rendering methods to be executed after the scene is rendered
  Calculate mouse coords manually relative to the window and to the render texture GUI element
     - Don't use GUI events as we require more precise control (do we?)

  Detect mouse clicks on the scene render target
      Forward those mouse coordinates to HandleManager
      It checks if screen ray intersects any handles and returns the handle if it does
         If handle is found it is activated and method returns
         Otherwise we mark the coordinates as selection start

  Detect mouse drag on the scene render target
    - If we have an active handle
         Forward mouse coordinates to the active handle so it can do its thing
         return
    - Otherwise its assumed we are dragging a selection
         Update selection endpoint and send it to ScenePicking
         Use Selection to select picked objects if any
         return

  Detect mouse release on scene render target
     If we have an active handle
        Clear active handle
        return
     Otheriwse its assumed we are dragging a selection
        Do nothing
        return