make water depth independent of view frustum

apps/openmw/mwrender/renderingmanager.cpp

@@ -279,11 +279,14 @@ namespace MWRender
         mViewDistance = Settings::Manager::getFloat("viewing distance", "Camera");
         mFieldOfView = Settings::Manager::getFloat("field of view", "Camera");
         mFirstPersonFieldOfView = Settings::Manager::getFloat("first person field of view", "Camera");
-        updateProjectionMatrix();
         mStateUpdater->setFogEnd(mViewDistance);
 
         mRootNode->getOrCreateStateSet()->addUniform(new osg::Uniform("near", mNearClip));
         mRootNode->getOrCreateStateSet()->addUniform(new osg::Uniform("far", mViewDistance));
+
+        mUniformNear = mRootNode->getOrCreateStateSet()->getUniform("near");
+        mUniformFar = mRootNode->getOrCreateStateSet()->getUniform("far");
+        updateProjectionMatrix();
     }
 
     RenderingManager::~RenderingManager()
@@ -889,6 +892,9 @@ namespace MWRender
         if (mFieldOfViewOverridden)
             fov = mFieldOfViewOverride;
         mViewer->getCamera()->setProjectionMatrixAsPerspective(fov, aspect, mNearClip, mViewDistance);
+
+        mUniformNear->set(mNearClip);
+        mUniformFar->set(mViewDistance);
     }
 
     void RenderingManager::updateTextureFiltering()

apps/openmw/mwrender/renderingmanager.hpp

@@ -83,6 +83,9 @@ namespace MWRender
         SceneUtil::UnrefQueue* getUnrefQueue();
         Terrain::World* getTerrain();
 
+        osg::Uniform* mUniformNear;
+        osg::Uniform* mUniformFar;
+
         void preloadCommonAssets();
 
         double getReferenceTime() const;

apps/openmw/mwrender/water.cpp

@@ -112,7 +112,7 @@ class ClipCullNode : public osg::Group
             }
 
             // move the plane back along its normal a little bit to prevent bleeding at the water shore
-            const float clipFudge = -6;
+            const float clipFudge = -5;
             modelViewMatrix->preMultTranslate(mCullPlane->getNormal() * clipFudge);
 
             cv->pushModelViewMatrix(modelViewMatrix, osg::Transform::RELATIVE_RF);

files/shaders/water_fragment.glsl

@@ -6,7 +6,7 @@
 
 // tweakables -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 
-const float VISIBILITY = 1200.0; // how far you can look through water
+const float VISIBILITY = 2.5;
 
 const float BIG_WAVES_X = 0.1; // strength of big waves
 const float BIG_WAVES_Y = 0.1;
@@ -31,7 +31,7 @@ const vec3 SUN_EXT = vec3(0.45, 0.55, 0.68);       //sunlight extinction
 
 const float SPEC_HARDNESS = 256.0;                 // specular highlights hardness
 
-const float BUMP_SUPPRESS_DEPTH = 0.03;            // at what water depth bumpmap will be supressed for reflections and refractions (prevents artifacts at shores)
+const float BUMP_SUPPRESS_DEPTH = 0.3;             // at what water depth bumpmap will be supressed for reflections and refractions (prevents artifacts at shores)
 
 const vec2 WIND_DIR = vec2(0.5f, -0.8f);
 const float WIND_SPEED = 0.2f;
@@ -76,15 +76,18 @@ uniform float near;
 uniform float far;
 uniform vec3 nodePosition;
 
-float linearizeDepth(float depth)  // helper for transforming water depth
+float frustumDepth;
+
+float linearizeDepth(float depth)  // takes <0,1> non-linear depth value and returns <0,1> linearized value
   {
     float z_n = 2.0 * depth - 1.0;
-    depth = 2.0 * near * far / (far + near - z_n * (far - near));
+    depth = 2.0 * near * far / (far + near - z_n * frustumDepth);
-    return depth - depthPassthrough;
+    return depth / frustumDepth;
   }
 
 void main(void)
 {
+    frustumDepth = abs(far - near);
     vec3 worldPos = position.xyz + nodePosition.xyz;
     vec2 UV = worldPos.xy / (8192.0*5.0) * 3.0;
     UV.y *= -1.0;
@@ -157,8 +160,13 @@ void main(void)
     fresnel = clamp(fresnel, 0.0, 1.0);
 
 #if REFRACTION
-    float realWaterDepth = linearizeDepth(texture2D(refractionDepthMap, screenCoords).x);
+    float normalization = frustumDepth / 1000;
-    float shore = clamp(realWaterDepth / (BUMP_SUPPRESS_DEPTH * (far - near)),0,1);
+    float depthSample = linearizeDepth(texture2D(refractionDepthMap,screenCoords).x) * normalization;
+    float depthSampleDistorted = linearizeDepth(texture2D(refractionDepthMap,screenCoords-(normal.xy*REFR_BUMP)).x) * normalization;
+    float surfaceDepth = linearizeDepth(gl_FragCoord.z) * normalization;
+    float realWaterDepth = depthSample - surfaceDepth;  // undistorted water depth in view direction, independent of frustum
+ 
+    float shore = clamp(realWaterDepth / BUMP_SUPPRESS_DEPTH,0,1);
 #else
     float shore = 1.0;
 #endif
@@ -180,10 +188,8 @@ void main(void)
     waterColor = waterColor * length(gl_LightModel.ambient.xyz);
 
 #if REFRACTION
-    float waterDepth = linearizeDepth(texture2D(refractionDepthMap, screenCoords-(normal.xy*REFR_BUMP)).x); 
-
     if (cameraPos.z > 0.0)
-        refraction = mix(refraction, waterColor, clamp(waterDepth/VISIBILITY, 0.0, 1.0));
+        refraction = mix(refraction, waterColor, clamp(depthSampleDistorted/VISIBILITY, 0.0, 1.0));
 
     gl_FragData[0].xyz = mix( mix(refraction,  scatterColour,  lightScatter),  reflection,  fresnel) + specular * gl_LightSource[0].specular.xyz;
 #else