Unity URP Lit shader自定义阴影颜色

kyuskoj · 发表于 2021-12-7 19:55

由于需要修改URP实现，首先需要将插件源码移动到Package目录避免被Unity还原。

原URP目录在 Library\PackageCache内，直接剪切即可

1.打开Lit.shader文件，在Properties块内添加可编辑属性
2.shader添加自定义阴影的Keyword
Shader &#34;Universal Render Pipeline/Lit&#34;
{
Properties
{
      ····省略····

      [Toggle] _ShadowColCustom(&#34;打开阴影颜色自定义&#34;, Float) = 0
      _ShadowColor(&#34;阴影颜色&#34;, Color) = (0,0,0,1)

      ····省略····
}
····省略····
SubShader
{
      // ------------------------------------------------------------------
      //  Forward pass. Shades all light in a single pass. GI + emission + Fog
      Pass
      {
         // Lightmode matches the ShaderPassName set in UniversalRenderPipeline.cs. SRPDefaultUnlit and passes with
         // no LightMode tag are also rendered by Universal Render Pipeline
         Name &#34;ForwardLit&#34;
         Tags{&#34;LightMode&#34; = &#34;UniversalForward&#34;}

         Blend[_SrcBlend][_DstBlend]
         ZWrite[_ZWrite]
         Cull[_Cull]

         HLSLPROGRAM
         // -------------------------------------
         // Material Keywords
         #pragma shader_feature_local _SHADOWCOLCUSTOM_ON
      }
   }
}

_SHADOWCOLCUSTOM_ON宏添加进第一个Pass内即可

3.为了支持SRP Batcher，需要将_ShadowColor添加进CBUFFER内，打开LitInput.hlsl源码进行修改

4.在源码中找到阴影部分实现，进行颜色的差值混合

#ifdef _SHADOWCOLCUSTOM_ON
half3 radiance = lerp(_ShadowColor, lightColor, lightAttenuation * _ShadowColor.a) * NdotL;
#else
half3 radiance = lightColor * lightAttenuation * NdotL;
#endif由于Lit的属性面板做了自定义，需要修改编辑器面板绘制部分的代码逻辑
1.找到LitShader.cs，找一个位置插入阴影颜色属性的绘制逻辑

private void DrawShadowColorProperties(Material material)
{
bool customShadowColor = material.IsKeywordEnabled(&#34;_SHADOWCOLCUSTOM_ON&#34;);

float viewWidth = EditorGUIUtility.currentViewWidth;
Rect drawRect = EditorGUILayout.GetControlRect();
Rect rc = drawRect;
rc.width = 140;
EditorGUI.LabelField(rc, &#34;自定义阴影颜色&#34;);

rc.width = viewWidth - 35;
EditorGUI.BeginChangeCheck();
customShadowColor = EditorGUI.Toggle(rc, &#34; &#34;, customShadowColor);
if (EditorGUI.EndChangeCheck())
{
      EditorUtility.SetDirty(material);
      Undo.RecordObject(material, &#34;&#34;);

      material.SetFloat(&#34;_ShadowColCustom&#34;, customShadowColor ? 1 : 0);

      MaterialChanged(material);
}
EditorGUI.BeginDisabledGroup(!customShadowColor);
{
      drawRect = EditorGUILayout.GetControlRect();

      rc = drawRect;
      rc.width = 140;
      EditorGUI.LabelField(rc, &#34;阴影颜色&#34;);

      rc.width = viewWidth - 35;
      EditorGUI.BeginChangeCheck();
      Color fogColor = EditorGUI.ColorField(rc, &#34; &#34;, material.GetColor(&#34;_ShadowColor&#34;));
      if (EditorGUI.EndChangeCheck())
      {
         EditorUtility.SetDirty(material);
         Undo.RecordObject(material, &#34;&#34;);
         material.SetColor(&#34;_ShadowColor&#34;, fogColor);
      }
}
EditorGUI.EndDisabledGroup();
}2.在BaseShaderGUI.cs内，找到对Keyword的修改逻辑，添加上我们自定义的Keyword处理

bool customShadowColor = false;
if (material.HasProperty(&#34;_ShadowColCustom&#34;))
{
customShadowColor = material.GetFloat(&#34;_ShadowColCustom&#34;) >= 0.5;
}
if (customShadowColor)
{
material.EnableKeyword(&#34;_SHADOWCOLCUSTOM_ON&#34;);
}
else
{
material.DisableKeyword(&#34;_SHADOWCOLCUSTOM_ON&#34;);
}
接下来我们回到编辑器，Lit的材质球面板会多出阴影自定义部分的编辑

自定义阴影颜色

到此，可以对物体进行阴影颜色自定义了

mypro334 · 发表于 2021-12-7 19:59

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Unity URP Lit shader自定义阴影颜色

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