How to draw flat triangles in 3D space?

Questions & Answers
1

I’m trying to draw simple, colored, flat triangles using three 3d coordinates, how would I do this? After some searching I came across this library “GL” which seems to do what I want, but I cannot get it to work. After reading the script reference I tried to make this script which runs in a simple cube gameobject:

using UnityEngine;
using System.Collections;

public class drawProjection : MonoBehaviour { 

	// Use this for initialization
	void Start () {


	}
	
	// Update is called once per frame
	void Update () {
	
		GL.PushMatrix();
		GL.Begin(GL.TRIANGLES);
		GL.Color(Color.red);
		GL.Vertex3(1,0,0);
		GL.Vertex3(0,1,0);
		GL.Vertex3(0,2,0);
		GL.End();
		GL.PopMatrix();
		
	}
}

But it does nothing. I’m very new to Unity, and I don’t even understand much of the lingo in the script reference so I don’t know where to begin at learning about this.

2

From the reference:

GL drawing commands execute
immediately. That means if you call
them in Update(), they will be
executed before the camera is rendered
(and the camera will most likely clear
the screen, making the GL drawing not
visible).

From the reference:

The usual place to call GL drawing is
most often in OnPostRender() from a
script attached to a camera

Attach this script to the Camera:

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {

	void OnPostRender() {
		GL.PushMatrix();
		GL.Begin(GL.TRIANGLES);
		GL.Color(Color.red);
		GL.Vertex3(1,0,0);
		GL.Vertex3(0,1,0);
		GL.Vertex3(0,2,0);
		GL.End();
		GL.PopMatrix();
	}
}