Writing an Editor Window that mimics the Scene View

@gilley033

I had that issue with small preview area. That's why I set preview camera pixelRect and aspect in Layout pass.

screenRect = new Rect(GUIUtility.GUIToScreenPoint(new Vector2(previewRect.x, previewRect.y)),new Vector2(previewRect.width, previewRect.height));

looks suspicious to me. Try:

screenRect = EditorGUIUtility.GUIToScreenRect(previewRect);

 

I need this code to work on pre 2019.1 where GUIToScreenRect is not available. I looked at the source code and that methdod just calls GUIToScreenPoint internally so I don't think this is an issue.

 

I went back to drawing the windows before EndAndDrawPreview is called. It's the only way I can get the handles to work correctly. I also changed how the previewRect dimensions are calculated to this:

Code (CSharp):

1. if(position.width < 1024)
2.     previewRect = new Rect(0, 0, position.width + (1024 - position.width), position.height);
3.  else
4.     previewRect = new Rect(0, 0, position.width, position.height);

This fixes the issue with the scene being cut off and the mouse position being off for the handles.

I still have the issue with all my window controls being off by (I'm fairly certain) 22 pixels, due to the toolbar at the top of the screen.

If anyone has any ideas on how to disable the toolbar I'd love to hear it. Adding an offset to Event.Current.mousePosition doesn't work for whatever reason.

 

And I figured it out. I didn't think this would work as previous attempts to provide a negative value for the window position have failed, but this code works:

Code (CSharp):

1. if(position.width < 1024)
2.      previewRect = new Rect(0, -22, position.width + (1024 - position.width), position.height);
3. else
4.      previewRect = new Rect(0, -22, position.width, position.height);

Edit: With this change you also have to offset the mouse by 22 pixels before drawing and using the handles, like so:

Code (CSharp):

1. mouseOffset = new Vector2(0f, 22f);
2. Event.current.mousePosition += mouseOffset;
3.  
4. Handles.SetCamera(SceneCamera);
5. DrawHandles();
6.  
7. Event.current.mousePosition -= mouseOffset;

 

Does anyone know the best way to go about drawing lots of meshes in the scene view created by the PreviewRenderUtility. I know there is a DrawMesh method available, but I would love to use DrawMeshInstanced instead. Unfortunatley, it is not working for me!

Here's the code I'm trying:

Code (CSharp):

1.  
2. Mesh mesh;
3. Vector3 size = new Vector3(.9f, .9f, .9f), location = new Vector3(.5f, .5f, 10f);
4.  
5. void OnGUI()
6. {
7.     //a lot of other code
8.     if(event == EventType.Repaint)
9.     {
10.         BeginPreview(previewRect);
11.         Render();
12.         EndAndDrawPreview(previewRect);
13.     }
14.     //more code . . .
15. }
16.  
17. void BeginPreview(Rect pos)
18. {
19.     preview.BeginPreview(pos, GUIStyle.none);
20. }
21.  
22. void Render()
23. {
24.     foreach (var light in preview.lights)
25.         light.enabled = true;
26.     var oldAllowPipes = Unsupported.useScriptableRenderPipeline;
27.     Unsupported.useScriptableRenderPipeline = false;
28.     RenderInstanced();
29.     SceneCamera.Render();
30.     Unsupported.useScriptableRenderPipeline = oldAllowPipes;
31. }
32.  
33. void EndAndDrawPreview(Rect pos)
34. {
35.     preview.EndAndDrawPreview(pos);
36. }
37.  
38. void RenderInstanced()
39. {
40.     if (mesh == null)
41.         mesh = (Mesh)AssetDatabase.LoadAssetAtPath("Assets/TerrainSlicing/EditorResources/Bevel_Cube.fbx", typeof(Mesh));
42.  
43.     Matrix4x4[] mArr = new Matrix4x4[1];
44.     Matrix4x4 m = Matrix4x4.TRS(location, Quaternion.identity, size);
45.     mArr[0] = m;
46.  
47.     //preview.DrawMesh(mesh, m, SharedLoadingPatternStatics.cellMaterial_InstancedOpaque, 0);
48.     //Graphics.DrawMesh(mesh, m, SharedLoadingPatternStatics.cellMaterial_InstancedOpaque, 1, SceneCamera);
49.     Graphics.DrawMeshInstanced(mesh, 0, SharedLoadingPatternStatics.cellMaterial_InstancedOpaque, mArr, 1, null, UnityEngine.Rendering.ShadowCastingMode.Off, false, 1, SceneCamera);
50. }

The two lines preview.DrawMesh and Grahics.DrawMesh both work. I don't know a lot about rendering, I think it's because DrawMeshInstanced does not get rendered with Camera.Render (which renders to a RenderTexture).

Any help would be great!