chore: checkpoint current workspace changes

engine/assets/builtin/shaders/forward-lit.shader

@@ -78,7 +78,7 @@ Shader "Builtin Forward Lit"
         return output;
     }
 
-    float ComputeShadowAttenuation(float3 positionWS)
+    float ComputeShadowAttenuation(float3 positionWS, float3 normalWS, float3 lightDirectionWS)
     {
     #ifndef XC_MAIN_LIGHT_SHADOWS
         return 1.0f;
@@ -87,7 +87,10 @@ Shader "Builtin Forward Lit"
             return 1.0f;
         }
 
-        const float4 shadowClip = mul(gWorldToShadowMatrix, float4(positionWS, 1.0f));
+        const float nDotL = saturate(dot(normalize(normalWS), normalize(lightDirectionWS)));
+        const float normalBiasWorld = gShadowOptions.y * gShadowOptions.z * (1.0f - nDotL);
+        const float3 shadowPositionWS = positionWS + normalize(normalWS) * normalBiasWorld;
+        const float4 shadowClip = mul(gWorldToShadowMatrix, float4(shadowPositionWS, 1.0f));
         if (shadowClip.w <= 0.0f) {
             return 1.0f;
         }
@@ -116,9 +119,28 @@ Shader "Builtin Forward Lit"
 
         const float receiverDepth = shadowNdc.z - gShadowBiasAndTexelSize.x;
     #endif
-        const float shadowDepth = ShadowMapTexture.Sample(ShadowMapSampler, shadowUv).r;
+        const float2 shadowTexelSize = gShadowBiasAndTexelSize.yz;
+        float visibility = 0.0f;
+    [unroll]
+        for (int offsetY = -1; offsetY <= 1; ++offsetY) {
+        [unroll]
+            for (int offsetX = -1; offsetX <= 1; ++offsetX) {
+                const float2 sampleUv =
+                    shadowUv + float2((float)offsetX, (float)offsetY) * shadowTexelSize;
+                if (sampleUv.x < 0.0f || sampleUv.x > 1.0f ||
+                    sampleUv.y < 0.0f || sampleUv.y > 1.0f) {
+                    visibility += 1.0f;
+                    continue;
+                }
+
+                const float shadowDepth = ShadowMapTexture.Sample(ShadowMapSampler, sampleUv).r;
+                visibility += receiverDepth <= shadowDepth ? 1.0f : 0.0f;
+            }
+        }
+
+        visibility *= (1.0f / 9.0f);
         const float shadowStrength = saturate(gShadowBiasAndTexelSize.w);
-        return receiverDepth <= shadowDepth ? 1.0f : (1.0f - shadowStrength);
+        return lerp(1.0f - shadowStrength, 1.0f, visibility);
     #endif
     }
 
@@ -207,7 +229,7 @@ Shader "Builtin Forward Lit"
             const float3 directionToLightWS = normalize(gMainLightDirectionAndIntensity.xyz);
             const float diffuse = saturate(dot(normalWS, directionToLightWS));
             const float shadowAttenuation =
-                diffuse > 0.0f ? ComputeShadowAttenuation(input.positionWS) : 1.0f;
+                diffuse > 0.0f ? ComputeShadowAttenuation(input.positionWS, normalWS, directionToLightWS) : 1.0f;
             lighting +=
                 gMainLightColorAndFlags.rgb *
                 (diffuse * gMainLightDirectionAndIntensity.w * shadowAttenuation);

engine/assets/builtin/shaders/shadow-caster.shader

@@ -62,6 +62,10 @@ Shader "Builtin Shadow Caster"
         {
             Name "ShadowCaster"
             Tags { "LightMode" = "ShadowCaster" }
+            Cull Back
+            ZWrite On
+            ZTest LEqual
+            Offset 1.0, 2
             HLSLPROGRAM
             #pragma target 4.5
             #pragma vertex MainVS