试了一下unity自带的阴影,发现有接缝问题,
上网找了一些解决方案,都非常庞大,
基本是要自己处理级联阴影
看了urp的build-in之后,想了一个比较暗黑的方式,简单处理一下,运行对比图如下,
左边是unity自带的级联阴影效果,右边是平滑后的级联阴影
思路比较简单,从unity内部函数中抽几个出来改造
计算当前像素点(世界坐标)位于哪个裁切球,代码如下:
强制取某个裁切球的级联阴影映射,代码如下:
本案例只处理第一个裁切球与第二个裁切球过渡效果,
其它的裁切球离摄像机比较远,处不处理影响不大,如果要处理,方法也是相同的
混合两个解析度的阴影代码如下
其它urp管线需要用到的pass DepthOnly ShadowCaster就不说明了,照抄就可以了,以便物体本身也能生成阴影
以下贴出完整的urp shader代码
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Shader "lsc/csm_shader"{ Properties { _MainTex("Texture", 2D) = "white" {} } SubShader { LOD 100 Tags{"RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline" "UniversalMaterialType" = "Lit" "IgnoreProjector" = "True" "ShaderModel" = "2.0"} Pass { Name "ForwardLit" Tags{"LightMode" = "UniversalForward"} HLSLPROGRAM #pragma vertex vert #pragma fragment frag #pragma exclude_renderers gles gles3 glcore #pragma target 4.5 #pragma multi_compile _ _MAIN_LIGHT_SHADOWS #pragma multi_compile _ _MAIN_LIGHT_SHADOWS_CASCADE #pragma multi_compile_fragment _ _ADDITIONAL_LIGHT_SHADOWS #pragma multi_compile_fragment _ _SHADOWS_SOFT #pragma vertex LitPassVertex #pragma fragment LitPassFragment #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl" #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl" struct appdata { float4 vertex : POSITION; float2 uv : TEXCOORD0; float3 normal : NORMAL; }; struct v2f { float2 uv : TEXCOORD0; float4 vertex : SV_POSITION; float3 normal : TEXCOORD2; float3 world_pos : TEXCOORD3; }; sampler2D _MainTex; float4 _MainTex_ST; v2f vert(appdata v) { v2f o; VertexPositionInputs vertexInput = GetVertexPositionInputs(v.vertex.xyz); o.vertex = vertexInput.positionCS;; o.uv = TRANSFORM_TEX(v.uv, _MainTex); o.normal = v.normal; o.world_pos = vertexInput.positionWS; return o; } //常规的计算csm纹理映射函数 //unity把所有的级联阴影刷在一个深度纹理 //通过切换shadow coord的方式取不同解析度的光源深度纹理 //每个解析度区间是用裁切球的方式 float4 anhei_TransformWorldToShadowCoord(float3 positionWS) { half cascadeIndex = ComputeCascadeIndex(positionWS); float4 shadowCoord = mul(_MainLightWorldToShadow[cascadeIndex], float4(positionWS, 1.0)); return float4(shadowCoord.xyz, cascadeIndex); } //自定义直接指定取某个区间段级联阴影 float4 anhei_TransformWorldToShadowCoord2(int idx, float3 positionWS) { half cascadeIndex = idx; float4 shadowCoord = mul(_MainLightWorldToShadow[cascadeIndex], float4(positionWS, 1.0)); return float4(shadowCoord.xyz, cascadeIndex); } //常规计算当前像素点(世界坐标)处于哪个裁切球 half anhei_ComputeCascadeIndex(float3 positionWS) { float3 fromCenter0 = positionWS - _CascadeShadowSplitSpheres0.xyz; float3 fromCenter1 = positionWS - _CascadeShadowSplitSpheres1.xyz; float3 fromCenter2 = positionWS - _CascadeShadowSplitSpheres2.xyz; float3 fromCenter3 = positionWS - _CascadeShadowSplitSpheres3.xyz; float4 distances2 = float4(dot(fromCenter0, fromCenter0), dot(fromCenter1, fromCenter1), dot(fromCenter2, fromCenter2), dot(fromCenter3, fromCenter3)); half4 weights = half4(distances2 < _CascadeShadowSplitSphereRadii); weights.yzw = saturate(weights.yzw - weights.xyz); return 4 - dot(weights, half4(4, 3, 2, 1)); } float4 frag(v2f i) : SV_Target { // sample the texture float4 col = tex2D(_MainTex, i.uv); float3 nml = normalize(i.normal.xyz); int cas_idx_1 = anhei_ComputeCascadeIndex(i.world_pos); Light light_1; Light light_0; half shadow_mix = 1.0f; float mix_fact = 0; if (cas_idx_1 == 0)//只处理第一个裁切球,其它裁切球的太远了,在画面上可能看不见 { float4 shadow_coord0 = anhei_TransformWorldToShadowCoord2(0, i.world_pos); light_0 = GetMainLight(shadow_coord0); float4 shadow_coord1 = anhei_TransformWorldToShadowCoord2(1, i.world_pos); light_1 = GetMainLight(shadow_coord1); shadow_mix = light_1.shadowAttenuation; //离第一个裁切球心距离 float3 fromCenter0 = i.world_pos - _CascadeShadowSplitSpheres0.xyz; float3 first_sphere_dis = length(fromCenter0); //第一个裁切球的半径 float first_sphere_rad = sqrt(_CascadeShadowSplitSphereRadii.x); //做一个简单的插值 mix_fact = clamp((first_sphere_dis) / (first_sphere_rad / 1.0f), 0.0f, 1.0f); shadow_mix = light_0.shadowAttenuation* (1 - mix_fact) + light_1.shadowAttenuation * mix_fact; } else { float4 shadow_coord1 = anhei_TransformWorldToShadowCoord2(1, i.world_pos); light_1 = GetMainLight(shadow_coord1); shadow_mix = light_1.shadowAttenuation; } col.rgb = shadow_mix * col.rgb; return col; } ENDHLSL } // ShadowCaster 将物体写入光源的深度纹理 // 使用自定义的shadow caster, urp会从光源处拍摄场影 pass { Tags{ "LightMode" = "ShadowCaster" } HLSLPROGRAM #pragma vertex vert #pragma fragment frag #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl" #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl" struct appdata { float4 vertex : POSITION; float3 normal : NORMAL; }; struct v2f { float4 pos : SV_POSITION; }; sampler2D _MainTex; float4 _MainTex_ST; float3 _LightDirection; v2f vert(appdata v) { v2f o; float3 world_pos = TransformObjectToWorld(v.vertex); float3 world_nml = TransformObjectToWorldNormal(v.normal); o.pos = TransformWorldToHClip(ApplyShadowBias(world_pos, world_nml, _LightDirection)); return o; } float4 frag(v2f i) : SV_Target { float4 color; color.xyz = float3(0.0, 0.0, 0.0); return color; } ENDHLSL } // DepthOnly 直接使用内置hlsl代码 Pass { Name "DepthOnly" Tags{"LightMode" = "DepthOnly"} ZWrite On ColorMask 0 Cull[_Cull] HLSLPROGRAM #pragma exclude_renderers gles gles3 glcore #pragma target 4.5 #pragma vertex DepthOnlyVertex #pragma fragment DepthOnlyFragment // ------------------------------------- // Material Keywords #pragma shader_feature_local_fragment _ALPHATEST_ON #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A //-------------------------------------- // GPU Instancing #pragma multi_compile_instancing #pragma multi_compile _ DOTS_INSTANCING_ON #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl" #include "Packages/com.unity.render-pipelines.universal/Shaders/DepthOnlyPass.hlsl" ENDHLSL } }} |
以上就是解决Unity urp级联阴影接缝问题的详细内容，更多关于Unity级联阴影的资料请关注服务器之家其它相关文章！
原文链接：https://blog.csdn.net/lsccsl/article/details/118161524
