Merge pull request #158 from Unity-Technologies/fog-fixes

Fog fixes

Author: Chman

PostProcessing/Resources/Shaders/AmbientOcclusion.cginc

@@ -69,6 +69,7 @@ float4 _OcclusionTexture_TexelSize;
 half _Intensity;
 float _Radius;
 float _Downsample;
+float3 _FogParams; // x: density, y: start, z: end
 
 // Accessors for packed AO/normal buffer
 fixed4 PackAONormal(fixed ao, fixed3 n)
@@ -220,6 +221,28 @@ float3 PickSamplePoint(float2 uv, float index)
     return v * l;
 }
 
+// Fog handling in forward
+half ComputeFog(float z)
+{
+    half fog = 0.0;
+#if FOG_LINEAR
+    fog = (_FogParams.z - z) / (_FogParams.z - _FogParams.y);
+#elif FOG_EXP
+    fog = exp2(-_FogParams.x * z);
+#else // FOG_EXP2
+    fog = _FogParams.x * z;
+    fog = exp2(-fog * fog);
+#endif
+    return saturate(fog);
+}
+
+float ComputeDistance(float depth)
+{
+    float dist = depth * _ProjectionParams.z;
+    dist -= _ProjectionParams.y;
+    return dist;
+}
+
 //
 // Distance-based AO estimator based on Morgan 2011 http://goo.gl/2iz3P
 //
@@ -282,6 +305,13 @@ half4 FragAO(VaryingsMultitex i) : SV_Target
     // Apply other parameters.
     ao = pow(ao * _Intensity / _SampleCount, kContrast);
 
+    // Apply fog when enabled (forward-only)
+#if !FOG_OFF
+    float d = Linear01Depth(SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv));
+    d = ComputeDistance(d);
+    ao *= ComputeFog(d);
+#endif
+
     return PackAONormal(ao, norm_o);
 }
 

PostProcessing/Resources/Shaders/AmbientOcclusion.shader

@@ -16,6 +16,7 @@ Shader "Hidden/Post FX/Ambient Occlusion"
             CGPROGRAM
                 #pragma vertex VertMultitex
                 #pragma fragment FragAO
+                #pragma multi_compile FOG_OFF FOG_LINEAR FOG_EXP FOG_EXP2
                 #define SOURCE_DEPTH
                 #include "AmbientOcclusion.cginc"
             ENDCG
@@ -27,6 +28,7 @@ Shader "Hidden/Post FX/Ambient Occlusion"
             CGPROGRAM
                 #pragma vertex VertMultitex
                 #pragma fragment FragAO
+                #pragma multi_compile FOG_OFF FOG_LINEAR FOG_EXP FOG_EXP2
                 #define SOURCE_DEPTHNORMALS
                 #include "AmbientOcclusion.cginc"
             ENDCG
@@ -38,6 +40,7 @@ Shader "Hidden/Post FX/Ambient Occlusion"
             CGPROGRAM
                 #pragma vertex VertMultitex
                 #pragma fragment FragAO
+                #pragma multi_compile FOG_OFF FOG_LINEAR FOG_EXP FOG_EXP2
                 #define SOURCE_GBUFFER
                 #include "AmbientOcclusion.cginc"
             ENDCG

PostProcessing/Resources/Shaders/Fog.shader

@@ -61,7 +61,7 @@ Shader "Hidden/Post FX/Fog"
 
             float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv);
             depth = Linear01Depth(depth);
-            float dist = ComputeDistance(depth) - _Start;
+            float dist = ComputeDistance(depth);
             half fog = 1.0 - ComputeFog(dist);
 
             return lerp(color, _FogColor, fog);
@@ -74,7 +74,7 @@ Shader "Hidden/Post FX/Fog"
             float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv);
             depth = Linear01Depth(depth);
             float skybox = depth < SKYBOX_THREASHOLD_VALUE;
-            float dist = ComputeDistance(depth) - _Start;
+            float dist = ComputeDistance(depth);
             half fog = 1.0 - ComputeFog(dist);
 
             return lerp(color, _FogColor, fog * skybox);

PostProcessing/Runtime/Components/AmbientOcclusionComponent.cs

@@ -10,6 +10,7 @@ static class Uniforms
         {
             internal static readonly int _Intensity         = Shader.PropertyToID("_Intensity");
             internal static readonly int _Radius            = Shader.PropertyToID("_Radius");
+            internal static readonly int _FogParams         = Shader.PropertyToID("_FogParams");
             internal static readonly int _Downsample        = Shader.PropertyToID("_Downsample");
             internal static readonly int _SampleCount       = Shader.PropertyToID("_SampleCount");
             internal static readonly int _OcclusionTexture1 = Shader.PropertyToID("_OcclusionTexture1");
@@ -103,6 +104,28 @@ public override void PopulateCommandBuffer(CommandBuffer cb)
             material.SetFloat(Uniforms._Downsample, settings.downsampling ? 0.5f : 1f);
             material.SetInt(Uniforms._SampleCount, (int)settings.sampleCount);
 
+            if (!context.isGBufferAvailable && RenderSettings.fog)
+            {
+                material.SetVector(Uniforms._FogParams, new Vector3(RenderSettings.fogDensity, RenderSettings.fogStartDistance, RenderSettings.fogEndDistance));
+
+                switch (RenderSettings.fogMode)
+                {
+                    case FogMode.Linear:
+                        material.EnableKeyword("FOG_LINEAR");
+                        break;
+                    case FogMode.Exponential:
+                        material.EnableKeyword("FOG_EXP");
+                        break;
+                    case FogMode.ExponentialSquared:
+                        material.EnableKeyword("FOG_EXP2");
+                        break;
+                }
+            }
+            else
+            {
+                material.EnableKeyword("FOG_OFF");
+            }
+
             int tw = context.width;
             int th = context.height;
             int ts = settings.downsampling ? 2 : 1;

PostProcessing/Runtime/Components/FogComponent.cs

@@ -1,4 +1,3 @@
-using System;
 using UnityEngine.Rendering;
 
 namespace UnityEngine.PostProcessing
@@ -39,7 +38,7 @@ public override DepthTextureMode GetCameraFlags()
 
         public override CameraEvent GetCameraEvent()
         {
-            return CameraEvent.BeforeImageEffectsOpaque;
+            return CameraEvent.AfterImageEffectsOpaque;
         }
 
         public override void PopulateCommandBuffer(CommandBuffer cb)
@@ -48,7 +47,8 @@ public override void PopulateCommandBuffer(CommandBuffer cb)
 
             var material = context.materialFactory.Get(k_ShaderString);
             material.shaderKeywords = null;
-            material.SetColor(Uniforms._FogColor, RenderSettings.fogColor);
+            var fogColor = GraphicsUtils.isLinearColorSpace ? RenderSettings.fogColor.linear : RenderSettings.fogColor;
+            material.SetColor(Uniforms._FogColor, fogColor);
             material.SetFloat(Uniforms._Density, RenderSettings.fogDensity);
             material.SetFloat(Uniforms._Start, RenderSettings.fogStartDistance);
             material.SetFloat(Uniforms._End, RenderSettings.fogEndDistance);