Drawing method using GL under URP

First, in the URP Next ,OnPostRender Will not be executed automatically . If you want to implement , Add code similar to the following ：

void OnEnable()
{
	RenderPipelineManager.endCameraRendering += EndCameraRendering;
}

void OnDisable()
{
	RenderPipelineManager.endCameraRendering -= EndCameraRendering;
}

void EndCameraRendering(ScriptableRenderContext context, Camera camera)
{
	OnPostRender();
}

void OnPostRender()
{
    // Draw code 
}

But in that case , It seems that the method doesn't need to be called OnPostRender, And the script does not need to be hung with Camera Component's GameObject On . The thing to note is that , This OnPostRender Will be in all Camera It works , If you need to use a specific Camera Drawing , Should be right EndCameraRendering Provided in the method Camera Parameters to judge , Look at this Camera Is it the camera you want to use . Similar to the following ：

void EndCameraRendering(ScriptableRenderContext context, Camera camera)
{
	if (camera == camMain) SceneHeightRender();
	if (camera == camUI) UIHeightRender();
}

First, let's take a look at the writing reference of two-dimensional drawing lines ：

	void UIHeightRender()
	{
		if (!mat) return;
		if (heights == null || heights.Length < 2) return;

		mat.SetColor("_Color", colorCurve);
		mat.SetPass(0);

		GL.PushMatrix();

		GL.LoadOrtho();

		GL.Begin(GL.LINE_STRIP);

		for (int i = 0; i < heights.Length; i++)
		{
			GL.Vertex3(wUnit * (i + 10), heights[i] * hUnit * multi, 0);
		}

		GL.End();

		GL.PopMatrix();
	}

Let's take another look at the writing reference of 3D rendering ：

	void SceneHeightRender()
	{
		if (!mat) return;
		if (monitoringPoints == null || monitoringPoints.Length < 2) return;

		GL.PushMatrix();

		GL.MultMatrix(Matrix4x4.TRS(Vector3.zero, Quaternion.identity, Vector3.one));

		mat.SetColor("_Color",colorSegment);
		mat.SetPass(0);
		foreach (MonitoringPoint monitoringPoint in monitoringPoints)
		{
			GL.Begin(GL.LINES);
			GL.Vertex(monitoringPoint.position);
			GL.Vertex(monitoringPoint.position + Vector3.up * monitoringPoint.height);
			GL.End();
		}

		mat.SetColor("_Color", colorBase);
		mat.SetPass(0);
		GL.Begin(GL.LINE_STRIP);
		foreach (MonitoringPoint monitoringPoint in monitoringPoints)
		{
			GL.Vertex(monitoringPoint.position);
		}
		GL.End();

		if (tops == null || tops.Length < 2) return;

		mat.SetColor("_Color", colorCurve);
		mat.SetPass(0);
		GL.Begin(GL.LINE_STRIP);
		foreach (Vector3 top in tops)
		{
			GL.Vertex(top);
		}
		GL.End();

		GL.PopMatrix();
	}

There is a main point to pay attention to , Namely
        mat.SetColor("_Color", color);
        mat.SetPass(0);

The execution order of these two methods should not be reversed , Otherwise, the drawing color may be wrong .

That's it :)