3d render inside inspector always black

I'm trying to display a 3d object inside the inspector, but it only shows black pixels.

Code (CSharp):

1.  
2. using UnityEngine;
3. using UnityEditor;
4. using System.Collections;
5. using System.Collections.Generic;
6. using System.Threading;
7.  
8. [CustomEditor(typeof(Biomes))]
9. public class BiomesEditor : Editor {
10.     private static int size = 256;
11.  
12.     // from https://docs.unity3d.com/ScriptReference/RenderTexture-active.html
13.     static public Texture2D GetRTPixels(RenderTexture rt) {
14.         RenderTexture currentActiveRT = RenderTexture.active;
15.         RenderTexture.active = rt;
16.         tex.ReadPixels(new Rect(0, 0, tex.width, tex.height), 0, 0);
17.         tex.Apply();
18.         RenderTexture.active = currentActiveRT;
19.         return tex;
20.     }
21.  
22.     private void RenderBiomesPreview(Biomes edit) {
23.         RenderTexture render = new RenderTexture(size, size, 16, RenderTextureFormat.ARGB32);
24.         if (!render.Create()) return;
25.         List<GameObject> destroyables = new List<GameObject>();
26.         destroyables.Add(new GameObject());
27.         Camera camera = destroyables[0].AddComponent<Camera>();
28.         destroyables[0].transform.position = new Vector3(0f, 1000f, -5f);
29.         camera.targetTexture = render;
30.         destroyables.Add(Object.Instantiate(edit.cube));
31.         destroyables[1].transform.position = new Vector3(0f, 1000f, 0f);
32.  
33.  
34.         EditorGUI.BeginDisabledGroup(true);
35.         Texture2D render_texture = BiomesEditor.GetRTPixels(render);
36.         EditorGUILayout.ObjectField(render_texture, typeof(Texture2D), false, GUILayout.Width(render_texture.width), GUILayout.Height(render_texture.height));
37.         EditorGUI.EndDisabledGroup();
38.  
39.         render.Release();
40.         foreach (GameObject obj in destroyables) Object.DestroyImmediate(obj);
41.     }
42.  
43.     public override void OnInspectorGUI() {
44.         Biomes edit = (Biomes)target;
45.  
46.         DrawDefaultInspector();
47.  
48.         RenderBiomesPreview(edit);
49.     }
50. }
51.  

Relevant fragment from Biomes.cs:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. [CreateAssetMenu]
6. public class Biomes : ScriptableObject {
7.     public GameObject cube;
8. }

'cube' it's just an instance of a 3d cube.

 

I've never rendered in this context but unless your materials are unlit, I imagine you might need a light.

 

I don't have any lightsource in the scene, so Unity should use global illuminance.
I have created a light in the camera position just in case, and the results were the same.

 

Also, if you remove the line that deletes all the objects created (

foreach (GameObject obj in destroyables) Object.DestroyImmediate(obj);

) and you go to the camera you can see the block.

 

OK, I had to call

camera.Render()

before mapping the RenderTexture into a Texture2D

 

Oh... yeah. Cameras like that call a lot.

 

silly cameras, always fussy