Detecting touch on a specific node

NeilDanson

I've got a CCSprite on a CCLayer and scrolling is handled by a CCFollow action.

I'm trying to detect a touch on the CCSprite, but I cant find the magic incantation to detect it reliably when the screen has scrolled. I'm not sure if I should be adding the CCEventListenerTouchOneByOne to the sprite, to the layer, what the 2nd optional parameter is when I create the CCEventListenerTouchOneByOne. Touch location seems to be in relation to the screen. The sprite will always be topmost, so I'm not worried about it being behind other nodes.

I must be missing something obvious, but Ive been Console.Writelining out positions and bounding rects of every conversion I can think of, and I'm losiong the will to live now!

Anyone any handy pointers?

kjpou1

Neil

Can you put together a small project for us to take a look at. That will help with tracking where the problem is.

NeilDanson

Using CocosSharp 1.6, this relies on a file called Sprite.png (mine is 100x100Px). You should be able to just copy/paste this into a new project.

`using CocosSharp;

namespace CocosTouchIssue
{
class AppDelegate : CCApplicationDelegate
{
public override void ApplicationDidFinishLaunching(CCApplication application, CCWindow mainWindow)
{
base.ApplicationDidFinishLaunching(application, mainWindow);
var scene = new CCScene(mainWindow);
var layer = new CCLayerColor(CCColor4B.AliceBlue);
scene.AddChild(layer);
var sprite = new CCSprite(new CCTexture2D("Sprite.png"));
layer.AddChild(sprite);
var follow = new CCFollow(sprite, new CCRect(0, 0, 3000, 600));
layer.RunAction(follow);

        sprite.PositionX = 1000;
        sprite.PositionY = 300;

        var touchEvent = new CCEventListenerTouchOneByOne();
        touchEvent.OnTouchBegan = (touch, _event) =>
        {
            var attempt1 = sprite.BoundingBox.ContainsPoint(touch.Location);
            var attempt2 = sprite.BoundingBoxTransformedToWorld.ContainsPoint(layer.ScreenToWorldspace(touch.Location));
            var attempt3 = sprite.BoundingBoxTransformedToWorld.ContainsPoint(sprite.ScreenToWorldspace(touch.Location));
            var attempt4 = sprite.BoundingBox.ContainsPoint(layer.ScreenToWorldspace(touch.Location));
            var attempt5 = sprite.BoundingBox.ContainsPoint(sprite.ScreenToWorldspace(touch.Location));
            //var attempt6 = sprite.BoundingBox.ContainsPoint(scene.ScreenToWorldspace(touch.Location)); Null Reference Exception
            var pt = layer.WorldToScreenspace(sprite.Position);
            var attempt6 = new CCRect(pt.X, pt.Y, sprite.ContentSize.Width, sprite.ContentSize.Height).ContainsPoint(touch.LocationOnScreen);
            return attempt1 || attempt2 || attempt3 || attempt4 || attempt5 || attempt6;
        };
        sprite.AddEventListener(touchEvent, sprite);
        mainWindow.DefaultDirector.PushScene(scene);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var app = new CCApplication(false, new CCSize(1024, 600));
        app.ApplicationDelegate = new AppDelegate();
        app.StartGame();
    }
}

}
`

NeilDanson

In fact - here's the file so you can just add it to a new project....(I'd missed the attach file option!)

(Edit: File wouldnt upload)

kjpou1

Neil

Try something like this your touchEvent.OnTouchBegan = (touch, _event) => delegate:

            var layerOffset = Layer.PositionWorldspace;
            var target = (CCSprite)touchEvent.CurrentTarget;
            var locationInNode = touch.Location;

            CCRect rect = target.BoundingBoxTransformedToWorld;
            rect.Origin += layerOffset;

            if (rect.ContainsPoint(locationInNode))
            {
                CCLog.Log("sprite began... x = {0}, y = {1}", locationInNode.X, locationInNode.Y);
                target.Opacity = 180;
                return true;
            }

NeilDanson

Thanks Kenneth - that worked perfectly. Was there a reference point for creating that or was it just through experience?

Many thanks!

DJP

@NeilDanson : you can use this by using BoundingBoxTransformedToParent.ContainsPoint(). ballSprite.BoundingBoxTransformedToParent.ContainsPoint(arg1.Location) in this manner in the HandleTouchBegan Method or in case you face any problem try to create separate listeners on the layer.