142 lines
4.2 KiB
HLSL
142 lines
4.2 KiB
HLSL
#ifndef WATER_REFLECTIONS_INCLUDED
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#define WATER_REFLECTIONS_INCLUDED
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl"
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareOpaqueTexture.hlsl"
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#define AIR_RI 1.000293
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//Schlick's BRDF fresnel
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float ReflectionFresnel(float3 worldNormal, float3 viewDir, float exponent)
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{
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float cosTheta = saturate(dot(worldNormal, viewDir));
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return pow(max(0.0, AIR_RI - cosTheta), exponent);
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}
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float AttenuateSSR(float2 uv)
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{
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float offset = min(1.0 - max(uv.x, uv.y), min(uv.x, uv.y));
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float result = offset / (0.1);
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result = saturate(result);
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return pow(result, 0.5);
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}
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void RaymarchSSR(float3 origin, float3 direction, uint samples, half stepSize, half thickness, out half2 sampleUV, out half valid, out half outOfBounds)
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{
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sampleUV = 0;
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valid = 0;
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outOfBounds = 0;
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direction *= stepSize;
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const half rcpStepCount = rcp(samples);
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UNITY_LOOP
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for(uint i = 0; i <= samples; i++)
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{
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origin += direction;
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direction *= 1+stepSize;
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//View-space to screen-space UV
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sampleUV = ComputeNormalizedDeviceCoordinates(origin, GetViewToHClipMatrix());
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if (any(sampleUV.xy < 0) || any(sampleUV.xy > 1))
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{
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outOfBounds = 1;
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valid = 0;
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break;
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}
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outOfBounds = AttenuateSSR(sampleUV);
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//Sample Mip0, gradient sampling cannot work with loops
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float deviceDepth = SAMPLE_TEXTURE2D_X_LOD(_CameraDepthTexture, sampler_CameraDepthTexture, sampleUV, 0).r;
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//Calculate view-space position from UV and depth
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//Not using the ComputeViewSpacePosition function, since this negates the Z-component
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float3 samplePos = ComputeWorldSpacePosition(sampleUV, deviceDepth, UNITY_MATRIX_I_P);
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if(distance(samplePos.z, origin.z) > length(direction) * thickness) continue;
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if(samplePos.z > origin.z)
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{
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valid = 1;
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return;
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}
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}
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}
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TEXTURE2D_X(_PlanarReflection);
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SAMPLER(sampler_PlanarReflection);
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float3 SampleReflectionProbes(float3 reflectionVector, float3 positionWS, float smoothness, float2 screenPos)
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{
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float3 probes = float3(0,0,0);
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#if UNITY_VERSION >= 202220
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probes = GlossyEnvironmentReflection(reflectionVector, positionWS, smoothness, 1.0, screenPos.xy).rgb;
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#elif UNITY_VERSION >= 202120
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probes = GlossyEnvironmentReflection(reflectionVector, positionWS, smoothness, 1.0).rgb;
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#else
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probes = GlossyEnvironmentReflection(reflectionVector, smoothness, 1.0).rgb;
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#endif
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return probes;
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}
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bool _WaterSSREnabled;
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float4 _WaterSSRParams;
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//X: Steps
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//Y: Step size
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//Z: Thickness
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#define SSR_SAMPLES 12
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#define SSR_STEPSIZE 0.5
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#define SSR_MAX_DISTANCE 100
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#define SSR_THICKNESS 1.0
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float3 SampleReflections(float3 reflectionVector, float smoothness, float4 screenPos, float3 positionWS, float3 normalWS, float3 viewDir, float2 pixelOffset, bool planarReflectionsEnabled)
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{
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#if !_RIVER || UNITY_VERSION >= 202220
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screenPos.xy += pixelOffset.xy * lerp(1.0, 0.1, unity_OrthoParams.w);
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screenPos /= screenPos.w;
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#endif
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const float3 probes = SampleReflectionProbes(reflectionVector, positionWS, smoothness, screenPos.xy);
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float3 reflections = probes;
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#if !_DISABLE_DEPTH_TEX
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if(_WaterSSREnabled)
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{
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const float3 positionVS = TransformWorldToView(positionWS);
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const float3 direction = TransformWorldToViewDir(reflectionVector);
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float2 ssrUV = 0;
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half ssrRayMask, ssrEdgeMask = 0;
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RaymarchSSR(positionVS, direction, SSR_SAMPLES, SSR_STEPSIZE, SSR_THICKNESS, ssrUV, ssrRayMask, ssrEdgeMask);
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const float3 reflectionSS = SampleSceneColor(ssrUV);
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reflections = lerp(reflections, reflectionSS, ssrRayMask * ssrEdgeMask);
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}
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#endif
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#if !_RIVER //Planar reflections are pointless on curved surfaces, skip
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if(planarReflectionsEnabled)
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{
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float4 planarReflections = SAMPLE_TEXTURE2D_X_LOD(_PlanarReflection, sampler_PlanarReflection, screenPos.xy, 0);
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//Terrain add-pass can output negative alpha values. Clamp as a safeguard against this
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planarReflections.a = saturate(planarReflections.a);
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reflections = lerp(reflections, planarReflections.rgb, planarReflections.a);
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}
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#endif
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return reflections;
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}
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#endif |