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Grammar

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edited Apr 29, 2018 at 15:03

EDIT: I might as well add a method that checks if the unit is in the viewport bounds and a utility method that calculate the bounds. Just so you why I am worried about performance.

Checking if bounds contain unit:

public bool IsWithinSelectionBounds( GameObject gameObject )
    {
        if (!isSelecting) {
            return false;
        }

        var camera = Camera.main;
        var viewportBounds = Utilities.GetViewportBounds( camera, point1, point2);

        return viewportBounds.Contains(camera.WorldToViewportPoint(gameObject.transform.position));
    }

Static utilities:

public static Bounds GetViewportBounds( Camera camera, Vector2 screenPosition1, Vector2 screenPosition2 )
{
    var cam = Camera.main;
    var v1 = cam.ScreenToViewportPoint( screenPosition1 );
    var v2 = cam.ScreenToViewportPoint( screenPosition2 );
    var min = Vector3.Min( v1, v2 );
    var max = Vector3.Max( v1, v2 );
    min.z = camera.nearClipPlane;
    max.z = camera.farClipPlane;

    var bounds = new Bounds();
    bounds.SetMinMax( min, max );
    return bounds;
}

EDIT: I might as well add a method that checks if the unit is in the viewport bounds and a utility method that calculate the bounds. Just so you why I am worried about performance.

Checking if bounds contain unit:

public bool IsWithinSelectionBounds( GameObject gameObject )
    {
        if (!isSelecting) {
            return false;
        }

        var camera = Camera.main;
        var viewportBounds = Utilities.GetViewportBounds( camera, point1, point2);

        return viewportBounds.Contains(camera.WorldToViewportPoint(gameObject.transform.position));
    }

Static utilities:

public static Bounds GetViewportBounds( Camera camera, Vector2 screenPosition1, Vector2 screenPosition2 )
{
    var cam = Camera.main;
    var v1 = cam.ScreenToViewportPoint( screenPosition1 );
    var v2 = cam.ScreenToViewportPoint( screenPosition2 );
    var min = Vector3.Min( v1, v2 );
    var max = Vector3.Max( v1, v2 );
    min.z = camera.nearClipPlane;
    max.z = camera.farClipPlane;

    var bounds = new Bounds();
    bounds.SetMinMax( min, max );
    return bounds;
}

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asked Apr 29, 2018 at 14:36

Lucián Blažek

Code optimalization - Mass selecting units (RTS)

Yo fellow game developers!

So recently gamedev became my favorite hobby and I started working on my RTS game module which would then let me create different RTS games with just few changes (W3 inpiration :3). Anyway I am new to optimalization since my previous games had quite serious optimalization issues so I need your help with a pieace of code!

I am having a mass selection of units with drawn rectangle on screen. I've got it all worked out but now I am wondering if there could be anything done about optimalization for cycling through list of units every time my mouse position changes even for a little bit.

This is inside my Update function. There is much more in there so i cut it out but this is the piece I am worried about:

    void Update(){
        //...previous code blah blah blah...
        if (Input.GetMouseButton(0)) {
            oldPos2 = point2;
            point2 = Input.mousePosition;
            if (oldPos2!=point2) {//performance optimalization
                Debug.Log ("Performing selection");
                if (Vector2.Distance(point1,point2) >= selBoxIniDist) {
                    isSelecting = true;
                    foreach (var item in Game.Units) {
                        if (IsWithinSelectionBounds (item.gameObject)) {
                            item.Selected = true;
                        } else {
                            item.Selected = false;
                        }
                    }
                }
            }
        }
        //...rest of the code here...
    }

So as i told you, there is no problem with the code. I just need your opinion if there could be any changes especialy to this part of the code. Or maybe general advices for optimalization.

Even tho I am checking every update if the mouse moved (so I dont cycle every update) I still feel like checking every "milimeter" 5 times if any of the units are contained in the viewport rectangle is a little bit overkill just for the selecting units. At the end of selection I usualy end up with around less than 100 cycles.

What do you think?

unity c#