Hdrp/decal transparent mip selection 1222437

com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl

@@ -686,36 +686,37 @@ TEMPLATE_3_FLT(RangeRemap, min, max, t, return saturate((t - min) / (max - min))
 // Texture utilities
 // ----------------------------------------------------------------------------
 
-float ComputeTextureLOD(float2 uvdx, float2 uvdy, float2 scale)
+float ComputeTextureLOD(float2 uvdx, float2 uvdy, float2 scale, float bias = 0.0)
 {
     float2 ddx_ = scale * uvdx;
     float2 ddy_ = scale * uvdy;
-    float d = max(dot(ddx_, ddx_), dot(ddy_, ddy_));
+    float  d    = max(dot(ddx_, ddx_), dot(ddy_, ddy_));
 
-    return max(0.5 * log2(d), 0.0);
+    return max(0.5 * log2(d) - bias, 0.0);
 }
 
-float ComputeTextureLOD(float2 uv)
+float ComputeTextureLOD(float2 uv, float bias = 0.0)
 {
     float2 ddx_ = ddx(uv);
     float2 ddy_ = ddy(uv);
 
-    return ComputeTextureLOD(ddx_, ddy_, 1.0);
+    return ComputeTextureLOD(ddx_, ddy_, 1.0, bias);
 }
 
 // x contains width, w contains height
-float ComputeTextureLOD(float2 uv, float2 texelSize)
+float ComputeTextureLOD(float2 uv, float2 texelSize, float bias = 0.0)
 {
     uv *= texelSize;
 
-    return ComputeTextureLOD(uv);
+    return ComputeTextureLOD(uv, bias);
 }
 
 // LOD clamp is optional and happens outside the function.
-float ComputeTextureLOD(float3 duvw_dx, float3 duvw_dy, float3 duvw_dz, float scale)
+float ComputeTextureLOD(float3 duvw_dx, float3 duvw_dy, float3 duvw_dz, float scale, float bias = 0.0)
 {
     float d = Max3(dot(duvw_dx, duvw_dx), dot(duvw_dy, duvw_dy), dot(duvw_dz, duvw_dz));
-    return 0.5 * log2(d * (scale * scale));
+
+    return max(0.5f * log2(d * (scale * scale)) - bias, 0.0);
 }
 
 

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -552,6 +552,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Diffusion Profile and Material references in HDRP materials are now correctly exported to unity packages. Note that the diffusion profile or the material references need to be edited once before this can work properly.
 
 ### Changed
+- Improve MIP selection for decals on Transparents
 - Color buffer pyramid is not allocated anymore if neither refraction nor distortion are enabled
 - Rename Emission Radius to Radius in UI in Point, Spot
 - Angular Diameter parameter for directional light is no longuer an advanced property

com.unity.render-pipelines.high-definition/Runtime/Material/Decal/DecalUtilities.hlsl

@@ -11,10 +11,10 @@ DECLARE_DBUFFER_TEXTURE(_DBufferTexture);
 void ApplyBlendNormal(inout float4 dst, inout uint matMask, float2 texCoords, uint mapMask, float3x3 decalToWorld, float blend, float lod)
 {
     float4 src;
-    src.xyz = mul(decalToWorld, UnpackNormalmapRGorAG(SAMPLE_TEXTURE2D_LOD(_DecalAtlas2D, _trilinear_clamp_sampler_DecalAtlas2D, texCoords, lod))) * 0.5f + 0.5f;
+    src.xyz = mul(decalToWorld, UnpackNormalmapRGorAG(SAMPLE_TEXTURE2D_LOD(_DecalAtlas2D, _trilinear_clamp_sampler_DecalAtlas2D, texCoords, lod))) * 0.5 + 0.5;
     src.w = blend;
-    dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);
-    dst.w = dst.w * (1.0f - src.w);
+    dst.xyz = src.xyz * src.w + dst.xyz * (1.0 - src.w);
+    dst.w = dst.w * (1.0 - src.w);
     matMask |= mapMask;
 }
 
@@ -26,8 +26,8 @@ void ApplyBlendDiffuse(inout float4 dst, inout uint matMask, float2 texCoords, f
     }
     src.w *= blend;
     blend = src.w;  // diffuse texture alpha affects all other channels
-    dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);
-    dst.w = dst.w * (1.0f - src.w);
+    dst.xyz = src.xyz * src.w + dst.xyz * (1.0 - src.w);
+    dst.w = dst.w * (1.0 - src.w);
     matMask |= mapMask;
 }
 
@@ -45,12 +45,12 @@ void ApplyBlendMask(inout float4 dbuffer2, inout float2 dbuffer3, inout uint mat
     src.z = scalingMAB.z * src.z;
     src.w = lerp(remappingAOS.z, remappingAOS.w, src.w);
     float maskBlend;
-    if (blendParams.x == 1.0f)	// normal blend source is mask blue channel
+    if (blendParams.x == 1.0)	// normal blend source is mask blue channel
         normalBlend = src.z * decalBlend;
     else
-        normalBlend = albedoBlend; // normal blend source is albedo alpha     
+        normalBlend = albedoBlend; // normal blend source is albedo alpha
 
-    if (blendParams.y == 1.0f)	// mask blend source is mask blue channel
+    if (blendParams.y == 1.0)	// mask blend source is mask blue channel
         maskBlend = src.z * decalBlend;
     else
         maskBlend = albedoBlend; // mask blend siurce is albedo alpha
@@ -102,31 +102,32 @@ void ApplyBlendMask(inout float4 dbuffer2, inout float2 dbuffer3, inout uint mat
         dbuffer3Mask = float2(1, 1); // M alpha, AO alpha
     }
 
-    dbuffer2.xyz = (dbuffer2Mask.xyz == 1) ? src.xyz * src.w + dbuffer2.xyz * (1.0f - src.w) : dbuffer2.xyz;
-    dbuffer2.w = (dbuffer2Mask.w == 1) ? dbuffer2.w * (1.0f - src.w) : dbuffer2.w;
+    dbuffer2.xyz = (dbuffer2Mask.xyz == 1) ? src.xyz * src.w + dbuffer2.xyz * (1.0 - src.w) : dbuffer2.xyz;
+    dbuffer2.w = (dbuffer2Mask.w == 1) ? dbuffer2.w * (1.0 - src.w) : dbuffer2.w;
 
-    dbuffer3.xy = (dbuffer3Mask.xy == 1) ? dbuffer3.xy * (1.0f - src.w) : dbuffer3.xy;
+    dbuffer3.xy = (dbuffer3Mask.xy == 1) ? dbuffer3.xy * (1.0 - src.w) : dbuffer3.xy;
 
     matMask |= mapMask;
 }
 
-
+// In order that the lod for with transpartent decal better match the lod for opaque decal
+// We use ComputeTextureLOD with bias == 0.5
 void EvalDecalMask(PositionInputs posInput, float3 positionRWSDdx, float3 positionRWSDdy, DecalData decalData,
     inout float4 DBuffer0, inout float4 DBuffer1, inout float4 DBuffer2, inout float2 DBuffer3, inout uint mask, inout float alpha)
 {
     // Get the relative world camera to decal matrix
     float4x4 worldToDecal = ApplyCameraTranslationToInverseMatrix(decalData.worldToDecal);
     float3 positionDS = mul(worldToDecal, float4(posInput.positionWS, 1.0)).xyz;
-    positionDS = positionDS * float3(1.0, -1.0, 1.0) + float3(0.5, 0.5f, 0.5);  // decal clip space
-    if ((all(positionDS.xyz > 0.0f) && all(1.0f - positionDS.xyz > 0.0f)))
+    positionDS = positionDS * float3(1.0, -1.0, 1.0) + float3(0.5, 0.5, 0.5);  // decal clip space
+    if ((all(positionDS.xyz > 0.0) && all(1.0 - positionDS.xyz > 0.0)))
     {
         float2 uvScale = float2(decalData.normalToWorld[3][0], decalData.normalToWorld[3][1]);
         float2 uvBias = float2(decalData.normalToWorld[3][2], decalData.normalToWorld[3][3]);
         positionDS.xz = positionDS.xz * uvScale + uvBias;
         positionDS.xz = frac(positionDS.xz);
 
         // clamp by half a texel to avoid sampling neighboring textures in the atlas
-        float2 clampAmount = float2(0.5f / _DecalAtlasResolution.x, 0.5f / _DecalAtlasResolution.y);
+        float2 clampAmount = float2(0.5 / _DecalAtlasResolution.x, 0.5 / _DecalAtlasResolution.y);
 
         float2 diffuseMin = decalData.diffuseScaleBias.zw + clampAmount;                                    // offset into atlas is in .zw
         float2 diffuseMax = decalData.diffuseScaleBias.zw + decalData.diffuseScaleBias.xy - clampAmount;    // scale relative to full atlas size is in .xy so total texture extent in atlas is (1,1) * scale
@@ -147,15 +148,15 @@ void EvalDecalMask(PositionInputs posInput, float3 positionRWSDdx, float3 positi
 
         float2 sampleDiffuseDdx = positionDSDdx.xz * decalData.diffuseScaleBias.xy; // factor in the atlas scale
         float2 sampleDiffuseDdy = positionDSDdy.xz * decalData.diffuseScaleBias.xy;
-        float lodDiffuse = ComputeTextureLOD(sampleDiffuseDdx, sampleDiffuseDdy, _DecalAtlasResolution);
+        float  lodDiffuse       = ComputeTextureLOD(sampleDiffuseDdx, sampleDiffuseDdy, _DecalAtlasResolution, 0.5);
 
-        float2 sampleNormalDdx = positionDSDdx.xz * decalData.normalScaleBias.xy;
-        float2 sampleNormalDdy = positionDSDdy.xz * decalData.normalScaleBias.xy;
-        float lodNormal = ComputeTextureLOD(sampleNormalDdx, sampleNormalDdy, _DecalAtlasResolution);
+        float2 sampleNormalDdx  = positionDSDdx.xz * decalData.normalScaleBias.xy;
+        float2 sampleNormalDdy  = positionDSDdy.xz * decalData.normalScaleBias.xy;
+        float  lodNormal        = ComputeTextureLOD(sampleNormalDdx, sampleNormalDdy, _DecalAtlasResolution, 0.5);
 
-        float2 sampleMaskDdx = positionDSDdx.xz * decalData.maskScaleBias.xy;
-        float2 sampleMaskDdy = positionDSDdy.xz * decalData.maskScaleBias.xy;
-        float lodMask = ComputeTextureLOD(sampleMaskDdx, sampleMaskDdy, _DecalAtlasResolution);
+        float2 sampleMaskDdx    = positionDSDdx.xz * decalData.maskScaleBias.xy;
+        float2 sampleMaskDdy    = positionDSDdy.xz * decalData.maskScaleBias.xy;
+        float  lodMask          = ComputeTextureLOD(sampleMaskDdx, sampleMaskDdy, _DecalAtlasResolution, 0.5);
 
         float albedoBlend = decalData.normalToWorld[0][3];
         float4 src = decalData.baseColor;
@@ -165,9 +166,9 @@ void EvalDecalMask(PositionInputs posInput, float3 positionRWSDdx, float3 positi
         alpha = alpha < albedoBlend ? albedoBlend : alpha;    // use decal alpha if it is higher than transparent alpha
 
         float albedoContribution = decalData.normalToWorld[1][3];
-        if (albedoContribution == 0.0f)
+        if (albedoContribution == 0.0)
         {
-            mask = 0;	// diffuse will not get modified						
+            mask = 0;	// diffuse will not get modified
         }
 
         float normalBlend = albedoBlend;
@@ -208,13 +209,13 @@ DecalSurfaceData GetDecalSurfaceData(PositionInputs posInput, inout float alpha)
 
 #if defined(_SURFACE_TYPE_TRANSPARENT) && defined(HAS_LIGHTLOOP)  // forward transparent using clustered decals
     uint decalCount, decalStart;
-    DBuffer0 = float4(0.0f, 0.0f, 0.0f, 1.0f);
-    DBuffer1 = float4(0.5f, 0.5f, 0.5f, 1.0f);
-    DBuffer2 = float4(0.0f, 0.0f, 0.0f, 1.0f);
+    DBuffer0 = float4(0.0, 0.0, 0.0, 1.0);
+    DBuffer1 = float4(0.5, 0.5, 0.5, 1.0);
+    DBuffer2 = float4(0.0, 0.0, 0.0, 1.0);
 #ifdef DECALS_4RT
-    DBuffer3 = float2(1.0f, 1.0f);
+    DBuffer3 = float2(1.0, 1.0);
 #else
-    float2 DBuffer3 = float2(1.0f, 1.0f);
+    float2 DBuffer3 = float2(1.0, 1.0);
 #endif
 
 #ifndef LIGHTLOOP_DISABLE_TILE_AND_CLUSTER