How do I detect mouse inputs on sprites that are on a render texture?

My scene and all textures are within 256x256 pixel space. I then take this and render it to a render texture. This render texture is then blit to the screen using the GUITexture in combination with the AspectUtility (to create letter/pillarboxing). I do all of this to achieve a blown up pixel style. The problem is that the standard OnMouseOver/Up/Down do not work with this new rendering.

How do I detect a mouse position on my sprites that are now rendered via a render texture (blown up)?

i feel you have made it to two cameras. One camera is for rendering the scene to a REnderTExture. the other one is to render the texture to screen with effect. I think it will be easier if you make it with normal image effect structure, which use OnRenderImage(RenderTexture src, RenderTexture dest) instead of two cameras. Otherwise, you will have to use Raycast for the mouse events

Got it working.

Vector2 mousePosition = AspectUtility.mousePosition;

Vector2 normalized = new Vector2(mousePosition.x / AspectUtility.screenWidth, mousePosition.y / AspectUtility.screenHeight);

Vector2 v = Camera.main.ScreenToWorldPoint(Camera.main.ViewportToScreenPoint(normalized));

Collider2D[] col = Physics2D.OverlapPointAll(v);

if (col.Length > 0)
{
    foreach (Collider2D c in col)
    {
        Debug.Log("hit " + c.name);
    }
}

Used some code from: http://forum.unity3d.com/threads/211708-Unity-2D-Raycast-from-mouse-to-screen