GL.LINES and GL functionality with LWRP

I'm hoping to use some of the GL.*() class of functions, in particular rendering with GL.LINES. However, I tried upgrading my project to the LWRP, and those functions no longer seem to work/render.

Is that in the roadmap for LWRP (or any of the custom render pipelines), is there a workaround for using GL.LINES currently, or is that something that I'd have to create custom on top of the LWRP?

 

Actually I imagine it's something related to this issue, which I'd posted earlier, or will have a similar response.

 

Previously, I was rending the lines in OnPostRender(), on the main camera:

Code (CSharp):

1. void OnPostRender() {
2.     GL.PushMatrix();
3.     lineMaterial.SetPass(0);
4.     GL.Begin(GL.LINES);
5.     foreach(var l in linesList) {
6.         GL.Vertex3(l.p0.x, l.p0.y, l.p0.z);
7.         GL.Vertex3(l.p1.x, l.p1.y, l.p1.z);
8.     }
9.     GL.End();
10.     GL.PopMatrix();
11.  
12.     return;
13. }

I've since migrated rendering to the objects themselves, using OnRenderObject():

Code (CSharp):

1. public void OnRenderObject() {
2.     GL.PushMatrix();
3.     lineMaterial.SetPass(0);
4.     GL.Begin(GL.LINES);
5.     foreach (var l in linesList) {
6.         GL.Vertex3(l.p0.x, l.p0.y, l.p0.z);
7.         GL.Vertex3(l.p1.x, l.p1.y, l.p1.z);
8.     }
9.     GL.End();
10.     GL.PopMatrix();
11.     return;
12. }

In both cases, the lines render properly in the legacy rendering system, but they don't render at all with the LWRP.

 

I have the same issue with GL.LINE_STRIP, worked with normal post processing, LW only displays the lines in scene view not game view. Same installs as nickfourtimes. I've tried 2018.3.3f1 and the latest beta 2019.1.0b1.

 

Sent.

 

Shall I provide the same or is there/will there be an open issue # to contribute to?

 

I recommend you send yours in. We can compare answers

 

Alrighty, I've submitted a bug along with a repro project; I can provide a case ID if that would help.

 

Looks like they've been able to reproduce the problem and have sent it along for investigation.

 

Are you winning? Doesn't look good my end, I'm told that GL is going to be deprecated in LWRP :/ Which pushes me back to the normal post processing.

 

I haven't heard back from them at all, but this was pretty much what I was expecting. Luckily using LWRP isn't a dealbreaker for me, and I can run fine with legacy rendering, but I was hoping to use LWRP to future-proof the project at least a little bit.

Hopefully folks will come up with a custom RP in the future that supports GL commands, but that's way outside my wheelhouse.

 

It's not the same but worth looking at if you haven't already...

http://www.everyday3d.com/blog/index.php/2010/03/15/3-ways-to-draw-3d-lines-in-unity3d/

scene: linesGR

 

Ok well thanks for everything phil. For the time being I'm going back to the regular v2 PostProcessing. When I have the time I'll likely implement the drawmesh for LW.

 

~ update ~

I've migrated along to Unity 2019.3.0b6, and it seems like the GL.Lines are working!

 

I've the same problem. When using LWRP OnRenderObject / OnPostRender is not called in game. My unity's edition is 2019.3.2f1，

 

what should i set up ?

 

Hm. I'm essentially calling this code in 2019.3.1f1:

Code (CSharp):

1.  
2.     void OnRenderObject() {
3.         myMaterial.SetPass(0);
4.         GL.Begin(GL.LINES);
5.         {
6.             GL.Vertex(from);
7.             GL.Vertex(to);
8.         }
9.         GL.End();
10.  
11.         return;
12.     }

...and it's working just fine. I'm using URP since the upgrade/rename, rather than LWRP, not sure if that changes anything.

 

Do you use 2D render ? I'm developing a 2D project, when i switch URP's render list to 2D render, OnRenderObject is not called.

 

I just tested using a 2D Renderer asset, and as you say it seems that OnRenderObject isn't called. It's marked as "Experimental" so maybe that's not implemented yet, or maybe it's not present by design, but there might be other threads about that.

 

All right, thanks

 

I understand this is an old thread. But this is very relevant to something I'm trying to do in URP/SRP.
I've asked many different people and I couldn't get the answer I need, for whatever reason.

I did a test on my end to see if GL.Begin(GL.LINES); (etc, etc) works, and it doesn't seem to be working for me. Although, I only tested it in a custom ScriptableRenderPass I am making. and not in "OnRenderObject".

But what I wanted to ask you about "CommandBuffer.DrawProcedural". Since you brought it up here. And I'm assuming you brought that function up because it is the only way to draw single-pixel-lines in URP/SRP using command buffers.
I am actually trying to do this as well, drawing basic lines. But I am having a hard time getting anything to show up on screen. This could be because I have very little experience with graphics API's and I'm making many amateur mistakes.

This is my code I have so far. It sits inside a ScriptableRenderPass and uses CommandBuffers. I am also leaving out other code so it's easier to read:

In the Frame Debugger of Unity, it does show that the "Draw Procedural" is happening, but under the "preview" button. It says "Vertices: 3" but "Indices: 0"
Even though it should say "Indices: 3"

Other people have told me that I need to supply the buffers to the material with the Material.SetBuffer function. But I have no clue how that's supposed to happen. I tested "myMaterial.SetBuffer(0,vertexBuffer)" as if the shader semantic "POSITION" is held in the "first index" of something. But that didn't change anything.

Code (CSharp):

1. public MyCustomPass() {
2.             myMaterial = new Material(Shader.Find("Sprites/Default"));
3.             ib = new GraphicsBuffer(GraphicsBuffer.Target.Index, 3, 4); // index buffer for vertices
4.             vb = new GraphicsBuffer(GraphicsBuffer.Target.Vertex, 3, 12); // vertex buffer
5.             vb.SetData(new List<Vector3> { new Vector3(0, 0, 0), new Vector3(1, 2, 1), new Vector3(2, 1, 2) });
6.             ib.SetData(new List<int>() { 0, 1, 2 });
7.          
8.             //myMaterial.SetBuffer("vertex", vb); NOT SURE IF THIS LINE IS NEEDED, OR CORRECT
9. }
10.  
11. public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData) {
12.     RenderTextureDescriptor descriptor = renderingData.cameraData.cameraTargetDescriptor;
13.     descriptor.depthBufferBits = 0;
14.     colorBuffer = renderingData.cameraData.renderer.cameraColorTarget;
15. }
16.  
17. public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData) {
18.     var cmd = CommandBufferPool.Get();
19.     Matrix4x4 matrix = Matrix4x4.TRS(Vector3.zero, Quaternion.identity, Vector3.one); //renderingData.cameraData.GetProjectionMatrix();
20.  
21.     using(new ProfilingScope(cmd, profilingTest)) {
22.         cmd.SetRenderTarget(colorBuffer,
23.             RenderBufferLoadAction.DontCare,
24.             RenderBufferStoreAction.Store,
25.             RenderBufferLoadAction.DontCare,
26.             RenderBufferStoreAction.DontCare);
27.         cmd.ClearRenderTarget(false, true, new Color(0f, 0.2f, 0.8f)); // just some color I picked
28.  
29.         cmd.DrawProcedural(ib, matrix, myMaterial, 0, MeshTopology.Lines, 3); // draw lines?
30.         // somehow, the index buffer has to be paired up with the vertex buffer
31.         // and I have no clue where that happens.
32.     }
33.  
34.     context.ExecuteCommandBuffer(cmd);
35.  
36.     CommandBufferPool.Release(cmd);
37. }

It's kinda sad also that you can't just do this with "DrawMesh". Because one of the things I might want to do with this is add a single-pixel outline around meshes. As you can see in the attached image. Maybe if there is a more effective way to achieve this, I would resort to that. But I understand that other graphics APIs like OpenGL do have support for drawing lines from vertex arrays, and it's disappointing that the support isn't as obvious.

 

CommandBuffer... reminds me on DirectX in the early 90's.
Back to the roots, Unity, back to the roots ;-)

Fun fact, came here after migrating my little Play Mode Editor, developed in Unity 2018 in Unity 2019, but Gizmo.Drawline() didn't read zBuffer anymore (as it does in 2018). So I tried Debug.Drawline() which has a zTest flag. This does exactly nothing (2019).

So I found an old GL.xxx solution to draw a line. Which seems to work fine.

But not in URP, it seems... Needs command buffers to draw a line now.

Didn't migrate just for fun, but because my editor needs Undo (Ctrl+Z). That behaved oddly. Reason is, even in Play Mode, when focused window is Game window, Unity catches Hotkeys and uses them in Editor. Not kidding. So you can do two things with one key stroke! Testing your game and edit it in the Editor!
So I found this new HotkeyManager- thinggy, not available in 2018, but in 2019 to solve the problem. But to go full circle, then the line render problem came up.

Yeah. 'nough said.