Tutorial High-Performance Line Rendering in Unity with GL.LINES - UnreliableCode Forums

DirectXRay

DirectX 12 / Vulkan Dev

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2y ago · May 18, 2024 5:00 PM

#1

When rendering dozens of snaplines, skeleton bones, and bounding boxes in Unity,

CSHARP

GUI.DrawTexture

can generate significant CPU overhead.

Using Unity's low-level
CODE
GL.LINES
pipeline for maximum FPS:

CSHARP

using UnityEngine;

public class GLESPRenderer : MonoBehaviour
{
    private static Material _lineMaterial;

    private static void CreateLineMaterial()
    {
        if (_lineMaterial == null)
        {
            Shader shader = Shader.Find("Hidden/Internal-Colored");
            _lineMaterial = new Material(shader) { hideFlags = HideFlags.HideAndDontSave };
            _lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
            _lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            _lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
            _lineMaterial.SetInt("_ZWrite", 0);
            _lineMaterial.SetInt("_ZTest", (int)UnityEngine.Rendering.CompareFunction.Always);
        }
    }

    public static void RenderSnapline(Vector3 screenFrom, Vector3 screenTo, Color color)
    {
        CreateLineMaterial();
        _lineMaterial.SetPass(0);

        GL.PushMatrix();
        GL.LoadPixelMatrix();
        GL.Begin(GL.LINES);
        GL.Color(color);

        GL.Vertex3(screenFrom.x, screenFrom.y, 0);
        GL.Vertex3(screenTo.x, screenTo.y, 0);

        GL.End();
        GL.PopMatrix();
    }
}

Call this inside

CODE

Camera.onPostRender

or your render hook for zero-overhead GPU line drawing!

When rendering dozens of snaplines, skeleton bones, and bounding boxes in Unity, [code=csharp]GUI.DrawTexture[/code] can generate significant CPU overhead.

[b]Using Unity's low-level [code]GL.LINES[/code] pipeline for maximum FPS:[/b]

[code=csharp]using UnityEngine;

public class GLESPRenderer : MonoBehaviour
{
    private static Material _lineMaterial;

private static void CreateLineMaterial()
    {
        if (_lineMaterial == null)
        {
            Shader shader = Shader.Find("Hidden/Internal-Colored");
            _lineMaterial = new Material(shader) { hideFlags = HideFlags.HideAndDontSave };
            _lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
            _lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            _lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
            _lineMaterial.SetInt("_ZWrite", 0);
            _lineMaterial.SetInt("_ZTest", (int)UnityEngine.Rendering.CompareFunction.Always);
        }
    }

public static void RenderSnapline(Vector3 screenFrom, Vector3 screenTo, Color color)
    {
        CreateLineMaterial();
        _lineMaterial.SetPass(0);

GL.PushMatrix();
        GL.LoadPixelMatrix();
        GL.Begin(GL.LINES);
        GL.Color(color);

GL.Vertex3(screenFrom.x, screenFrom.y, 0);
        GL.Vertex3(screenTo.x, screenTo.y, 0);

GL.End();
        GL.PopMatrix();
    }
}[/code]

Call this inside [code]Camera.onPostRender[/code] or your render hook for zero-overhead GPU line drawing!

DirectXRay · DirectX 12 & Vulkan Command Lists

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GlowShader

Shader & Overlay Artist

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Join Date: Oct 2023

Posts: 36

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2y ago · May 18, 2024 7:20 PM

#2

CODE

Hidden/Internal-Colored

with

CODE

GL.LoadPixelMatrix()

is the cleanest native way to draw lines in Unity. You can batch hundreds of lines between a single

CODE

GL.Begin(GL.LINES)

and

CODE

GL.End()

!

GlowShader | Shaders, Stencils & DirectX DrawLists

RustMechanic

Unity & IL2CPP Reverser

VIP

Rep: 295

Join Date: Nov 2022

Posts: 32

Thanks: 74

2y ago · May 19, 2024 11:05 AM

#3

Batching all entity lines in one GL pass dropped our render frame time from 4ms down to under 0.2ms. Massive performance boost!

RustMechanic | IL2CPP & Unity Engine Analysis

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High-Performance Line Rendering in Unity with GL.LINES

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