Return the position(x,y) of the pixel when Clicked a Sprite

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Hi Guys, i have a Question i hope you could help me. This is my problem, when i click an Sprite2D the mouse gives me WOLRD Coordinates, but i want the Sprite Coordinates. Example: Y have an 50x50 Sprite and i click on the middle of it. I want a return that indicates me the coordinate of the sprite, that will be 24,24. I Hope you understand.

Thnks Guys for your time. :)

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Answer by robertbu · Oct 24, 2014 at 04:26 AM

If you are willing to:

Supply the pixel width and pixel height to the script
Supply the units to pixels value in the spript
Use an Orthographic camera
Set the Pivot of the sprite to the Bottom left
Single texture (not an atlas)

Then you can do something simple like this:

 #pragma strict
  
  var pixelWidth = 76.0;
  var pixelHeight = 150.0;
  var unitsToPixels = 100.0;
  
 function OnMouseDown() {
 
     // assumes an orthographic camera
     var pos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
     pos.z = transform.position.z;
     pos = transform.InverseTransformPoint(pos);
     
     var xPixel : int = Mathf.RoundToInt(pos.x * unitsToPixels);
     var yPixel : int = Mathf.RoundToInt(pos.y * unitsToPixels);
     
     Debug.Log("("+xPixel+", "+yPixel+")");
 }

The more you stray from the above list of criteria (or want to automate so that you don't have to input the date) the more complicated the script will be to calculate the position. Note that using a Quad with a MeshCollider makes this functionality trivial.

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NivekJump · Oct 24, 2014 at 02:15 PM 0

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Im Using a Sprite, and i Just need pixel color when i click in the Sprite... A Var Color32 and i need to be acurrate actually i can take the pixel color but when i Build the project for Windows, because the resolution change the script doesnt work fine. And when i used GetPixelColor() The method needs a position, but the Input$$anonymous$$ouse gives me the world coordinates, and i need the sprite coordinates. (If i click the pixel in the middle it would be 24x,24y) And this wont work... But thnks!!

robertbu · Oct 24, 2014 at 11:28 PM 0

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i need the sprite coordinates. (If i click the pixel in the middle it would be 24x,24y) And this wont work.

This code, properly setup would give you (24,24) if you click on the sprite. $$anonymous$$aking the conversion from world to pixels for a sprite is not an easy thing to do. Here is the above code taken a bit further. It assumes/requires the following:

Orthographic camera
No rotation of the sprite at the start of the game
Single texture sprite (won't work for an atlas or if the sprite is otherwise mapped into a texture.
The texture must be read/write enabled.

The pivot of the sprite needs to be the bottom left. Other pivots could be supported but would require code changes.

private var pixelWidth : int; private var pixelHeight : int; private var unitsToPixels : float; private var tex : Texture2D;

function Start() { var sr : SpriteRenderer = GetComponent.(); if (sr == null || sr.sprite.packed || !Camera.main.orthographic) { Debug.Log("Setup not correct to use this code"); return; }

    pixelWidth = sr.sprite.rect.width;
      pixelHeight = sr.sprite.rect.height;
      unitsToPixels = pixelWidth / sr.bounds.size.x * transform.localScale.x;
      tex = sr.sprite.texture;
  }
  
 function On$$anonymous$$ouseDown() {
 
     // assumes an orthographic camera
     var pos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
     pos.z = transform.position.z;
     pos = transform.InverseTransformPoint(pos);
     
     var xPixel : int = $$anonymous$$athf.RoundToInt(pos.x * unitsToPixels);
     var yPixel : int = $$anonymous$$athf.RoundToInt(pos.y * unitsToPixels);
     
     var color32 : Color32 = tex.GetPixel(xPixel, yPixel);
     Debug.Log("("+xPixel+", "+yPixel+")  " + color32);
 }

AhmadYusaf robertbu · Jul 14, 2021 at 11:41 AM 0

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@robertbu Can you please modify the above code for sprite that has pivot set to its Center rather than Bottom Left?

thanks in advance

AhmadYusaf · Jun 05, 2021 at 10:43 AM 0

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This was helpful . Thank you very much. this works

Return the position(x,y) of the pixel when Clicked a Sprite

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