From 688e804548861d3b12009ab414da05e58438aae7 Mon Sep 17 00:00:00 2001
From: Capostrophic <alexdobrohotov@yandex.ru>
Date: Fri, 24 Apr 2020 13:21:49 +0300
Subject: [PATCH] Fix simple water with radial fog enabled

---
 components/sceneutil/waterutil.cpp  | 3 +++
 files/shaders/objects_fragment.glsl | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/components/sceneutil/waterutil.cpp b/components/sceneutil/waterutil.cpp
index 562b0ee73..b98a19ae8 100644
--- a/components/sceneutil/waterutil.cpp
+++ b/components/sceneutil/waterutil.cpp
@@ -74,6 +74,9 @@ namespace SceneUtil
 
         stateset->setRenderBinDetails(renderBin, "RenderBin");
 
+        // Let the shader know we're dealing with simple water here.
+        stateset->addUniform(new osg::Uniform("simpleWater", true));
+
         return stateset;
     }
 }
diff --git a/files/shaders/objects_fragment.glsl b/files/shaders/objects_fragment.glsl
index 31e929a90..81884feac 100644
--- a/files/shaders/objects_fragment.glsl
+++ b/files/shaders/objects_fragment.glsl
@@ -49,6 +49,8 @@ uniform vec2 envMapLumaBias;
 uniform mat2 bumpMapMatrix;
 #endif
 
+uniform bool simpleWater = false;
+
 varying float euclideanDepth;
 varying float linearDepth;
 
@@ -180,7 +182,11 @@ void main()
 
     gl_FragData[0].xyz += getSpecular(normalize(viewNormal), normalize(passViewPos.xyz), shininess, matSpec) * shadowing;
 #if @radialFog
-    float fogValue = clamp((euclideanDepth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
+    float depth = euclideanDepth;
+    // For the less detailed mesh of simple water we need to recalculate depth on per-pixel basis
+    if (simpleWater)
+        depth = length(passViewPos);
+    float fogValue = clamp((depth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
 #else
     float fogValue = clamp((linearDepth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
 #endif