Unity Shader URP 学习 ShadowCaster

urp管线的自学hlsl之路 第十二篇 ShadowCaster和SRP batcher

对艺术家的SRP Batcher的简单理�?/a>

问题阐述

在URP管线下，需要投影，会采用直接调用官方的ShadowCaster pass(UsePass “Universal Render Pipeline/Lit/ShadowCaster�?。这样会出现问题,会让该shader无法进行SRP Batcher。如下图�?/p>

SRP Batcher

什么是SRP Batcher�?/span>

下面是官方的相关文档�?/p>

SRP Batcher：加快渲染速度�?/a>

SRP 全称为Scriptable Render Pipeline，其中一部分就是SRP Batcher，主要用途在渲染过程中加速CPU。加速的原因如下�?/p>

• Each material content is now persistent in GPU memory
• A dedicated code is managing a large “per object�?GPU CBUFFER

如何使用SRP Batcher�?/span>

• 可以使用C#进行开�?figure class="highlight plaintext">

  1	GraphicsSettings.useScriptableRenderPipelineBatching = true;

• 材质兼容的要�?ol>
• The object must be in a mesh. It cannot be a particle or a skinned mesh.（对象不能是粒子或者蒙皮mesh�?/li>
• You must use a Shader that is compatible with the SRP Batcher. All Lit and Unlit Shaders in HDRP and LWRP fit this requirement.(必须使用兼容的SHADER)
• Shader的要�?ol>
• All built-in engine properties must be declared in a single CBUFFER named “UnityPerDraw�? For example, unity_ObjectToWorld, or unity_SHAr.
• All Material properties must be declared in a single CBUFFER named “UnityPerMaterial�?

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pass { //该pass只把主灯光空间的深度图写到了shadowmap�?addlight灯光空间目前没有写进�?导致模型无法投射addlight的阴�?但是整shader可以接受addlight的阴�?/span> Tags { "LightMode"="ShadowCaster" } HLSLPROGRAM #pragma vertex vertshadow #pragma fragment fragshadow v2f vertshadow(a2v i) { v2f o; Light MainLight=GetMainLight(); float3 posWS=TransformObjectToWorld(i.vertex.xyz); float3 nDirWS=TransformObjectToWorldNormal(i.normal.xyz); o.pos=TransformWorldToHClip(ApplyShadowBias(posWS,nDirWS,MainLight.direction)); //Z反向 #if UNITY_REVERSED_Z o.pos.z=min(o.pos.z,o.pos.w*UNITY_NEAR_CLIP_VALUE); #else o.pos.z=max(o.pos.z,o.pos.w*UNITY_NEAR_CLIP_VALUE); #endif return o; } half4 fragshadow(v2f i):SV_TARGET{ return 0; } ENDHLSL }