1.简介
随着Unity6的发布,URP17也已经可以上手使用,相对旧的版本改动较大的是加入了
RenderGraph、STP、Foveated rendering、GPU Resident Drawer等功能,部分功能只需要开关参数即可使用,
而GRD更像是Gpu driven管线下的SRP Batches升级,RenderGraph相较于HDRP之前使用的版本换了一套API。
最大的不同是,使用URP17编写Feature时,必须依赖于RenderGraph进行编写,接下来就来介绍一下。
1.1 相关Demo
目前URP17比较容易找到的学习Demo如下:
- URP17 Package内自带的Samples
- Fantasy Kingdom (https://assetstore.unity.com/packages/essentials/tutorial-projects/fantasy-kingdom-in-unity-6-urp-298128)
- 在Unity Hub可以直接下载的Universal 3D sample(包含3个场景)
2.RenderGraph
打开任意URP的示例场景查看,RenderGraphView上各图标含义如下:
- 说明这是一个外部置入的RenderTexture
- 红色方块说明存在写入操作
- 绿色方块指存在读取操作(红绿方块说明读写操作)
- 该图标说明标记了全局RenderTexture
而顶部表明当前渲染一帧的各个Pass,左侧是各类RT。
URP17同时保留了旧的Feature逻辑与RenderGraph逻辑(打开任意pass文件为例):
public class DistortTunnelPass_Tunnel : ScriptableRenderPass
{
class PassData
{
public Renderer tunnelObject;
public Material tunnelMaterial;
}
#pragma warning disable 618, 672 // Type or member is obsolete, Member overrides obsolete member
// Unity calls the Configure method in the Compatibility mode (non-RenderGraph path)
public override void Configure(CommandBuffer cmd, RenderTextureDescriptor cameraTextureDescripor)
{
}
// Unity calls the Execute method in the Compatibility mode
public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
{
}
#pragma warning restore 618, 672
// Unity calls the RecordRenderGraph method to add and configure one or more render passes in the render graph system.
public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameData)
{
}
}
参考时忽略掉Configure和Execute的逻辑,执行逻辑关注RecordRenderGraph函数。
2.1 操作方式的改变
在RenderGraph中,之前的RTHandle由于不在该系统中托管,进入RenderGraph的材质都需要调用API进行转换,
转换为RendeGraph的RT后,无需考虑释放操作:
RenderTextureDescriptor textureProperties = new RenderTextureDescriptor(Screen.width, Screen.height, RenderTextureFormat.Default, 0);
TextureHandle textureHandle = UniversalRenderer.CreateRenderGraphTexture(renderGraph, textureProperties, "My texture", false);
相关文档:
https://docs.unity3d.com/Manual/urp/render-graph-create-a-texture.html
此外RenderGraph对于空调用的pass,也会剔除进行优化,使用者需要手动标记以防止被剔除。
2.1 RecordRenderGraph
在该函数内可组织渲染逻辑,pass相关的逻辑需放在对应的代码块中,例如:
using (var builder = renderGraph.AddRasterRenderPass<PassData>(passName, out _))
{
builder.UseTexture(rt1);
builder.SetRenderAttachment(resourceData.activeColorTexture, 0);
builder.SetRenderFunc<PassData>((data, context) =>
{
MaterialPropertyBlock materialPropertyBlock = new MaterialPropertyBlock();
materialPropertyBlock.SetTexture("_BlitTexture", rt1);
materialPropertyBlock.SetVector("_BlitScaleBias", new Vector4(1, 1, 0, 0));
context.cmd.DrawProcedural(Matrix4x4.identity, material, 0, MeshTopology.Triangles, 3, 1, materialPropertyBlock);
});
}
URP提供了多种RenderPass,例如处理光栅化相关逻辑使用RasterRenderPass组织相关逻辑。
在RenderPass的代码块中可使用builder对象配置RenderTarget、标记材质的读写等
而具体的pass绘制逻辑则在SetRenderFunc代码块中。
RecordRenderGraph内可以调用多次AddRenderPass,但URP并没有整理旧API的代码和相关工具类,
以至于容易使用旧的API导致报错,这点需要注意。
3.编写Feature
3.1 Blit与SetTarget
从前有句俗话"切RT的性能消耗相当于半个pass",Unity SRP在几个版本的升级都在逐渐强调不切RenderTarget直接绘制,
如Cockpit Demo的屏幕空间描边。
3.2 屏幕模糊Demo
下面通过屏幕模糊Demo案例,演示URP17下pass的编写。
通过外部EnqueuePass的方式,在场景中通过控制器脚本添加该Pass,
MyBlurSceneController.cs:
using UnityEngine;
using UnityEngine.Rendering.Universal;
using UnityEngine.Rendering;
public class MyBlurSceneController : MonoBehaviour
{
public Material material;
[Range(2, 15)] public int blurPasses = 3;
[Range(0, 4)] public int downSample = 0;
[Range(0.0f, 10f)] public float offset = 0.2f;
public RenderPassEvent injectionPoint = RenderPassEvent.BeforeRenderingPostProcessing;
public int injectionPointOffset = 0;
public ScriptableRenderPassInput inputRequirements = ScriptableRenderPassInput.Color;
public CameraType cameraType = CameraType.Game;
private MyBlurPass mMyBlurPass;
private void OnEnable()
{
SetupPass();
RenderPipelineManager.beginCameraRendering += OnBeginCamera;
}
private void OnDisable()
{
RenderPipelineManager.beginCameraRendering -= OnBeginCamera;
}
public virtual void SetupPass()
{
mMyBlurPass = new MyBlurPass();
mMyBlurPass.renderPassEvent = injectionPoint + injectionPointOffset;
mMyBlurPass.material = material;
mMyBlurPass.ConfigureInput(inputRequirements);
}
public virtual void OnBeginCamera(ScriptableRenderContext ctx, Camera cam)
{
if (mMyBlurPass == null || material == null)
return;
if ((cam.cameraType & cameraType) == 0) return;
mMyBlurPass.blurPasses = blurPasses;
mMyBlurPass.downSample = downSample;
mMyBlurPass.offset = offset;
cam.GetUniversalAdditionalCameraData().scriptableRenderer.EnqueuePass(mMyBlurPass);
}
}
MyBlurPass.cs:
using UnityEngine;
using UnityEngine.Rendering.RenderGraphModule;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
using UnityEngine.Rendering.RenderGraphModule.Util;
public class MyBlurPass : ScriptableRenderPass
{
public class PassData
{
public TextureHandle tempRt1;
public TextureHandle tempRt2;
}
public Material material;
[Range(2, 15)] public int blurPasses = 3;
[Range(1, 4)] public int downSample = 1;
[Range(0.0f, 10f)] public float offset = 0.2f;
public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameData)
{
var resourceData = frameData.Get<UniversalResourceData>();
var passData = new PassData();
var w = Screen.width >> downSample;
var h = Screen.height >> downSample;
RenderTextureDescriptor textureProperties = new RenderTextureDescriptor(w, h, RenderTextureFormat.Default, 0);
passData.tempRt1 = UniversalRenderer.CreateRenderGraphTexture(renderGraph, textureProperties, "MyBlurPassTempRt1", false);
textureProperties = new RenderTextureDescriptor(w, h, RenderTextureFormat.Default, 0);
passData.tempRt2 = UniversalRenderer.CreateRenderGraphTexture(renderGraph, textureProperties, "MyBlurPassTempRt2", false);
var rt1 = passData.tempRt1;
var rt2 = passData.tempRt2;
//将屏幕RT Blit到rt1上
var para = new RenderGraphUtils.BlitMaterialParameters(resourceData.activeColorTexture, rt1, material, 0);
renderGraph.AddBlitPass(para, "MyBlurPassBlitFirst");
material.SetFloat("_SampleOffset", offset);
//模糊迭代
for (int i = 0; i < blurPasses - 1; ++i)
{
para = new RenderGraphUtils.BlitMaterialParameters(rt1, rt2, material, 0);
renderGraph.AddBlitPass(para, $"MyBlurPassBlit_{i}");
var tmp = rt1;
rt1 = rt2;
rt2 = tmp;
}
//通过直接绘制的方式,将模糊RT绘制到屏幕上
using (var builder = renderGraph.AddRasterRenderPass<PassData>(passName, out _))
{
builder.UseTexture(rt1);
builder.SetRenderAttachment(resourceData.activeColorTexture, 0);
builder.SetRenderFunc<PassData>((data, context) =>
{
MaterialPropertyBlock materialPropertyBlock = new MaterialPropertyBlock();
materialPropertyBlock.SetTexture("_BlitTexture", rt1);
materialPropertyBlock.SetVector("_BlitScaleBias", new Vector4(1, 1, 0, 0));
context.cmd.DrawProcedural(Matrix4x4.identity, material, 0, MeshTopology.Triangles, 3, 1, materialPropertyBlock);
});
}
}
}
接着在ShaderGraph中连出模糊的逻辑,注意Blit对应的参数_BlitTexture、_BlitScaleBias:
最后在场景中挂载控制器以及材质球,即可使用该模糊Pass。