koobas.hobune.stream
Using GL to draw after OnGUI
I know the execution order of the things inside Unity (including that OnPostRender() is called before OnGUI()). The thing is that I want to be able to draw lines with GL over some GUI textures. I've done some research on this and someone (do not remember where I saw it...) said to use OnPostRender as a coroutine. Is this correct? (Because when I tried it didn't work for me and no one had replied/voted on his answer)
The code I have is the following:
void Update () {
StartCoroutine(OnPostRender());
}
void OnGUI () {
/*
Drawing texture
*/
}
IEnumerator OnPostRender() {
/*
Drawing lines with GL
*/
yield return new WaitForEndOfFrame ();
}
Is GUI being drawn after because of a mistake I made, or is it just not possible to achieve this way?
Thanks in advance
In any case, if it was to work, your GL draw code would have to be after the yield, not before it.
I understand that, but if I do it then the code won't even run
//c# example
using UnityEngine;
public class lineOverTexture : MonoBehaviour {
private static readonly Color lineColor = new Color (1f, 0f, 0f, 0.88f);
// Use this for initialization
void Start () {
CreateLineMaterial();
}
public Texture aTexture;
void OnGUI() {
GUI.DrawTexture(new Rect(10, 10, 60, 60), aTexture, ScaleMode.ScaleToFit);
if (Event.current.type != EventType.Repaint)
return;
DrawLines();
}
// Update is called once per frame
void Update () {
}
private void DrawLines()
{
lineMaterial.SetPass(0);
GL.PushMatrix ();
GL.Begin (GL.LINES);
GL.Color (lineColor);
DrawLine(new Vector2(10.0f, 10.0f), new Vector2(70.0f, 10.0f));
DrawLine(new Vector2(70.0f, 10.0f), new Vector2(70.0f, 70.0f));
DrawLine(new Vector2(70.0f, 70.0f), new Vector2(10.0f, 70.0f));
DrawLine(new Vector2(10.0f, 70.0f), new Vector2(10.0f, 10.0f));
GL.End ();
GL.PopMatrix ();
}
private void DrawLine (Vector2 p1, Vector2 p2)
{
GL.Vertex (p1);
GL.Vertex (p2);
}
private Material lineMaterial;
private void CreateLineMaterial()
{
if( !lineMaterial ) {
lineMaterial = new Material( "Shader \"Lines/Colored Blended\" {" +
"SubShader { Pass { " +
" Blend SrcAlpha OneMinusSrcAlpha " +
" ZWrite Off Cull Off Fog { Mode Off } " +
" BindChannels {" +
" Bind \"vertex\", vertex Bind \"color\", color }" +
"} } }" );
lineMaterial.hideFlags = HideFlags.HideAndDontSave;
lineMaterial.shader.hideFlags = HideFlags.HideAndDontSave;
}
}
}
