GUI Button not working (Unexpected Symbol)

Questions & Answers
1

Here’s my script, for some reason it says there’s an expected symbol & parsing error.

But if I take away the GUI Button line on line twelve it works fine.

I just want a GUI Texture to show up when I click on a mesh

Here’s my script:
using UnityEngine;
using System.Collections;

public class OnClick : MonoBehaviour {
	public Texture2D texture = null;
	public float x = 0;
	public float y = 0;
	public float x2 = 0;
	public float y2 = 0;
	void OnMouseDown (){
		if (Input.GetKey ("mouse 0")) {
		GUI.Button(new Rect(x,y, x2,y2), texture)
		}
	}
}
2

you need to put the Gui inside the OnGUI function

3

public class OnClick : MonoBehaviour {
public Texture2D texture = null;
public float x = 0;
public float y = 0;
public float x2 = 0;
public float y2 = 0;

    void OnGUI() {
        if ( ! texture ) {
            Debug.LogError("Please assign a texture on the inspector");
            return;
        }

        if ( GUI.Button(new Rect(x,y, x2,y2), texture) )
            Debug.Log( "Do Something" );
    }
}

Here’s a link to the documentation for GUI.Button if you need it: Unity - Scripting API: GUI.Button

4

GUI items only can appear inside the OnGUI function (or some function called by OnGUI). You could in this case set a variable that enables the GUI item - which should be a GUI.Label or GUI.DrawTexture instead of GUI.Button (a button responds to the mouse click, what may cause weird collateral effects). For instance:

...
private bool enableTexture;

void OnMouseDown (){
    enableTexture = true; // enable GUI when mouse pressed over object
}

void OnMouseUp (){
    enableTexture = false; // disable GUI when mouse button released
}

void OnGUI (){
    if (enableTexture){
        GUI.Label(new Rect(x,y, x2,y2), texture);
    }
}

And remember to end the instructions with a semicolon, like @AyAMrau pointed out.