Drawning Line Problem useing custom class

Questions & Answers
1

hey i want to draw line useing custom class:
using System;
using UnityEngine;

public class Drawing
{
    public static Texture2D lineTex;

    public static void DrawLine(Rect rect) { DrawLine(rect, GUI.contentColor, 1.0f); }
    public static void DrawLine(Rect rect, Color color) { DrawLine(rect, color, 1.0f); }
    public static void DrawLine(Rect rect, float width) { DrawLine(rect, GUI.contentColor, width); }
    public static void DrawLine(Rect rect, Color color, float width) { DrawLine(new Vector2(rect.x, rect.y), new Vector2(rect.x + rect.width, rect.y + rect.height), color, width); }
    public static void DrawLine(Vector2 pointA, Vector2 pointB) { DrawLine(pointA, pointB, GUI.contentColor, 1.0f); }
    public static void DrawLine(Vector2 pointA, Vector2 pointB, Color color) { DrawLine(pointA, pointB, color, 1.0f); }
    public static void DrawLine(Vector2 pointA, Vector2 pointB, float width) { DrawLine(pointA, pointB, GUI.contentColor, width); }
    public static void DrawLine(Vector2 pointA, Vector2 pointB, Color color, float width)
    {
        Matrix4x4 matrix = GUI.matrix;
        if (!lineTex) { lineTex = new Texture2D(1, 1); }

        Color savedColor = GUI.color;
        GUI.color = color;
        float angle = Vector3.Angle(pointB - pointA, Vector2.right);
        if (pointA.y > pointB.y) { angle = -angle; }

        GUIUtility.ScaleAroundPivot(new Vector2((pointB - pointA).magnitude, width), new Vector2(pointA.x, pointA.y + 0.5f));
        GUIUtility.RotateAroundPivot(angle, pointA);
        GUI.DrawTexture(new Rect(pointA.x, pointA.y, 1, 1), lineTex);
        GUI.matrix = matrix;
        GUI.color = savedColor;
    }
}

and when in my script i use

Drawing.DrawLine(_temp, sphere[i, j].transform.position, Color.black);

i got errors:

NullReferenceException: Object
reference not set to an instance of an
object UnityEngine.GUI.DrawTexture
(Rect position, UnityEngine.Texture
image, ScaleMode scaleMode, Boolean
alphaBlend, Single imageAspect) (at
C:/BuildAgent/work/812c4f5049264fad/Runtime/ExportGenerated/Editor/GUI.cs:155)
UnityEngine.GUI.DrawTexture (Rect
position, UnityEngine.Texture image)
(at
C:/BuildAgent/work/812c4f5049264fad/Runtime/ExportGenerated/Editor/GUI.cs:152)
Drawing.DrawLine (Vector2 pointA,
Vector2 pointB, Color color, Single
width) (at Assets/Drawing.cs:67)
Drawing.DrawLine (Vector2 pointA,
Vector2 pointB, Color color) (at
Assets/Drawing.cs:30) Main.OnEnter
(System.String name) (at
Assets/Main.cs:123)
UnityEngine.GameObject:SendMessage(String,
Object) focus:OnMouseDown() (at
Assets/focus.cs:7)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32,
Int32)

2

Since you are using GUI calls, you will need to make these calls from inside an OnGUI() function. If you don’t, you’ll get a null reference like this one.

On another note: while it’s not causing you null reference problem, GUI.DrawTexture() takes screen coordinates. It looks like you are passing world coordinates to DrawLine method, and I don’t see any code making the conversion.