修改水

Packages/com.waveharmonic.crest/Runtime/Shaders/Surface/Foam.hlsl

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+// Crest Water System
+// Copyright © 2024 Wave Harmonic. All rights reserved.
+
+#ifndef CREST_WATER_FOAM_H
+#define CREST_WATER_FOAM_H
+
+#include "Packages/com.waveharmonic.crest/Runtime/Shaders/Library/Settings.Crest.hlsl"
+#include "Packages/com.waveharmonic.crest/Runtime/Shaders/Library/Macros.hlsl"
+#include "Packages/com.waveharmonic.crest/Runtime/Shaders/Library/Globals.hlsl"
+#include "Packages/com.waveharmonic.crest/Runtime/Shaders/Library/Texture.hlsl"
+#include "Packages/com.waveharmonic.crest/Runtime/Shaders/Library/Flow.hlsl"
+
+#if (CREST_SHIFTING_ORIGIN != 0)
+#include "Packages/com.waveharmonic.crest.shifting-origin/Runtime/Shaders/ShiftingOrigin.hlsl"
+#endif
+
+m_CrestNameSpace
+
+half WhiteFoamTexture
+(
+    const TiledTexture i_Texture,
+    const half i_Foam,
+    const half i_Feather,
+    const float2 i_WorldXZ0,
+    const float2 i_WorldXZ1,
+    const float2 i_TexelOffset,
+    const half i_LodAlpha,
+    const Cascade i_CascadeData0
+)
+{
+    const float2 uvOffset = i_TexelOffset + g_Crest_Time * i_Texture._speed / 32.0;
+    // Scale with lods to get multiscale detail. 10 is magic number that gets the
+    // material 'scale' slider into an intuitive range.
+    const float scale = i_Texture._scale * i_CascadeData0._Scale / 10.0;
+
+    half ft = lerp
+    (
+        i_Texture.Sample((i_WorldXZ0 + uvOffset) / scale).r,
+        i_Texture.Sample((i_WorldXZ1 + uvOffset) / (2.0 * scale)).r,
+        i_LodAlpha
+    );
+
+    // Black point fade.
+    half result = saturate(1.0 - i_Foam);
+    return smoothstep(result, result + i_Feather, ft);
+}
+
+half MultiScaleFoamAlbedo
+(
+    const TiledTexture i_Texture,
+    const half i_Feather,
+    const half i_FoamData,
+    const Cascade i_CascadeData0,
+    const Cascade i_CascadeData1,
+    const half i_LodAlpha,
+    const float2 i_UndisplacedXZ
+)
+{
+    float2 worldXZ0 = i_UndisplacedXZ;
+    float2 worldXZ1 = i_UndisplacedXZ;
+
+#if (CREST_SHIFTING_ORIGIN != 0)
+    // Apply tiled floating origin offset. Only needed if:
+    //  - _FoamScale is a non integer value
+    //  - _FoamScale is over 48
+    worldXZ0 -= ShiftingOriginOffset(i_Texture, i_CascadeData0);
+    worldXZ1 -= ShiftingOriginOffset(i_Texture, i_CascadeData1);
+#endif // CREST_SHIFTING_ORIGIN
+
+    return WhiteFoamTexture(i_Texture, i_FoamData, i_Feather, worldXZ0, worldXZ1, (float2)0.0, i_LodAlpha, i_CascadeData0);
+}
+
+half2 MultiScaleFoamNormal
+(
+    const TiledTexture i_Texture,
+    const half i_Feather,
+    const half i_NormalStrength,
+    const half i_FoamData,
+    const half i_FoamAlbedo,
+    const Cascade i_CascadeData0,
+    const Cascade i_CascadeData1,
+    const half i_LodAlpha,
+    const float2 i_UndisplacedXZ,
+    const float i_PixelZ
+)
+{
+    float2 worldXZ0 = i_UndisplacedXZ;
+    float2 worldXZ1 = i_UndisplacedXZ;
+
+#if (CREST_SHIFTING_ORIGIN != 0)
+    // Apply tiled floating origin offset. Only needed if:
+    //  - _FoamScale is a non integer value
+    //  - _FoamScale is over 48
+    worldXZ0 -= ShiftingOriginOffset(i_Texture, i_CascadeData0);
+    worldXZ1 -= ShiftingOriginOffset(i_Texture, i_CascadeData1);
+#endif // CREST_SHIFTING_ORIGIN
+
+    // 0.25 is magic number found through tweaking.
+    const float2 dd = float2(0.25 * i_PixelZ * i_Texture._texel, 0.0);
+    const half whiteFoam_x = WhiteFoamTexture(i_Texture, i_FoamData, i_Feather, worldXZ0, worldXZ1, dd.xy, i_LodAlpha, i_CascadeData0);
+    const half whiteFoam_z = WhiteFoamTexture(i_Texture, i_FoamData, i_Feather, worldXZ0, worldXZ1, dd.yx, i_LodAlpha, i_CascadeData0);
+
+    // Compute a foam normal - manually push in derivatives. If I used blend
+    // smooths all the normals towards straight up when there is no foam.
+    // Gets material slider into friendly range.
+    const float magicStrengthFactor = 0.01;
+    return magicStrengthFactor * i_NormalStrength * half2(whiteFoam_x - i_FoamAlbedo, whiteFoam_z - i_FoamAlbedo) / dd.x;
+}
+
+half MultiScaleFoamAlbedo
+(
+    const Flow i_Flow,
+    const TiledTexture i_Texture,
+    const half i_Feather,
+    const half i_Foam,
+    const Cascade i_CascadeData0,
+    const Cascade i_CascadeData1,
+    const half i_LodAlpha,
+    const float2 i_UndisplacedXZ
+)
+{
+    return MultiScaleFoamAlbedo
+    (
+        i_Texture,
+        i_Feather,
+        i_Foam,
+        i_CascadeData0,
+        i_CascadeData1,
+        i_LodAlpha,
+        i_UndisplacedXZ - i_Flow._Flow * i_Flow._Offset0
+    ) * i_Flow._Weight0 + MultiScaleFoamAlbedo
+    (
+        i_Texture,
+        i_Feather,
+        i_Foam,
+        i_CascadeData0,
+        i_CascadeData1,
+        i_LodAlpha,
+        i_UndisplacedXZ - i_Flow._Flow * i_Flow._Offset1
+    ) * i_Flow._Weight1;
+}
+
+half2 MultiScaleFoamNormal
+(
+    const Flow i_Flow,
+    const TiledTexture i_Texture,
+    const half i_Feather,
+    const half i_NormalStrength,
+    const half i_FoamData,
+    const half i_FoamAlbedo,
+    const Cascade i_CascadeData0,
+    const Cascade i_CascadeData1,
+    const half i_LodAlpha,
+    const float2 i_UndisplacedXZ,
+    const float i_PixelZ
+)
+{
+    return MultiScaleFoamNormal
+    (
+        i_Texture,
+        i_Feather,
+        i_NormalStrength,
+        i_FoamData,
+        i_FoamAlbedo,
+        i_CascadeData0,
+        i_CascadeData1,
+        i_LodAlpha,
+        i_UndisplacedXZ - i_Flow._Flow * i_Flow._Offset0,
+        i_PixelZ
+    ) * i_Flow._Weight0 + MultiScaleFoamNormal
+    (
+        i_Texture,
+        i_Feather,
+        i_NormalStrength,
+        i_FoamData,
+        i_FoamAlbedo,
+        i_CascadeData0,
+        i_CascadeData1,
+        i_LodAlpha,
+        i_UndisplacedXZ - i_Flow._Flow * i_Flow._Offset1,
+        i_PixelZ
+    ) * i_Flow._Weight1;
+}
+
+void ApplyFoamToSurface
+(
+    half i_Foam,
+    const half2 i_Normal,
+    const half3 i_Albedo,
+    const half i_Occlusion,
+    const half i_Smoothness,
+    const half i_Specular,
+    const bool i_Underwater,
+    inout half3 io_Albedo,
+    inout half3 io_NormalWS,
+    inout half3 io_Emission,
+    inout half io_Occlusion,
+    inout float io_Smoothness,
+    inout half3 io_Specular
+)
+{
+    // Apply foam to surface.
+    io_Albedo = lerp(io_Albedo, i_Albedo, i_Foam);
+    io_Emission *= 1.0 - i_Foam;
+    io_Occlusion = lerp(io_Occlusion, i_Occlusion, i_Foam);
+    io_Smoothness = lerp(io_Smoothness, i_Smoothness, i_Foam);
+    io_NormalWS.xz -= i_Normal;
+    io_NormalWS = normalize(io_NormalWS);
+
+    // Foam Transmission
+    if (i_Underwater)
+    {
+        // Foam will be black when not facing the sun. This is a hacky way to have foam lit
+        // as if it had transmission.
+        // There is still ugliness around the edges. There will either be black or
+        // incorrect reflections depending on the magic value.
+        io_NormalWS.y *= i_Foam > 0.15 ? -1.0 : 1.0;
+        io_Specular = lerp(io_Specular, i_Specular, i_Foam);
+    }
+}
+
+m_CrestNameSpaceEnd
+
+#endif