use a dynamic falloff range for soft effect and use shader flags

components/nifosg/nifloader.cpp

@@ -2708,7 +2708,8 @@ namespace NifOsg
                             stateset->setAttributeAndModes(polygonOffset, osg::StateAttribute::ON);
                         }
                         if (shaderprop->softEffect())
-                            SceneUtil::setupSoftEffect(*node, shaderprop->mFalloffDepth, true);
+                            SceneUtil::setupSoftEffect(
+                                *node, shaderprop->mFalloffDepth, true, shaderprop->mFalloffDepth);
                         break;
                     }
                     default:

components/sceneutil/extradata.cpp

@@ -15,7 +15,7 @@
 
 namespace SceneUtil
 {
-    void setupSoftEffect(osg::Node& node, float size, bool falloff)
+    void setupSoftEffect(osg::Node& node, float size, bool falloff, float falloffDepth)
     {
         static const osg::ref_ptr<SceneUtil::AutoDepth> depth = new SceneUtil::AutoDepth(osg::Depth::LESS, 0, 1, false);
 
@@ -23,6 +23,7 @@ namespace SceneUtil
 
         stateset->addUniform(new osg::Uniform("particleSize", size));
         stateset->addUniform(new osg::Uniform("particleFade", falloff));
+        stateset->addUniform(new osg::Uniform("softFalloffDepth", falloffDepth));
         stateset->setAttributeAndModes(depth, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
 
         node.setUserValue(Misc::OsgUserValues::sXSoftEffect, true);
@@ -35,6 +36,8 @@ namespace SceneUtil
 
         std::string source;
 
+        constexpr float defaultFalloffDepth = 300.f; // arbitrary value that simply looks good with common cases
+
         if (node.getUserValue(Misc::OsgUserValues::sExtraData, source) && !source.empty())
         {
             YAML::Node root = YAML::Load(source);
@@ -47,8 +50,9 @@ namespace SceneUtil
                 {
                     auto size = it.second["size"].as<float>(45.f);
                     auto falloff = it.second["falloff"].as<bool>(false);
+                    auto falloffDepth = it.second["falloffDepth"].as<float>(defaultFalloffDepth);
 
-                    setupSoftEffect(node, size, falloff);
+                    setupSoftEffect(node, size, falloff, falloffDepth);
                 }
             }
 
@@ -56,7 +60,8 @@ namespace SceneUtil
         }
         else if (osgParticle::ParticleSystem* partsys = dynamic_cast<osgParticle::ParticleSystem*>(&node))
         {
-            setupSoftEffect(node, partsys->getDefaultParticleTemplate().getSizeRange().maximum, false);
+            setupSoftEffect(
+                node, partsys->getDefaultParticleTemplate().getSizeRange().maximum, false, defaultFalloffDepth);
         }
 
         traverse(node);

components/sceneutil/extradata.hpp

@@ -15,7 +15,7 @@ namespace osg
 
 namespace SceneUtil
 {
-    void setupSoftEffect(osg::Node& node, float size, bool falloff);
+    void setupSoftEffect(osg::Node& node, float size, bool falloff, float falloffDepth);
 
     class ProcessExtraDataVisitor : public osg::NodeVisitor
     {

docs/source/reference/modding/custom-shader-effects.rst

@@ -31,13 +31,15 @@ This setting can either be activated in the OpenMW launcher or changed in `setti
 
 Variables.
 
-+---------+--------------------------------------------------------------------------------------------------------+---------+---------+
-| Name    | Description                                                                                            | Type    | Default |
-+---------+--------------------------------------------------------------------------------------------------------+---------+---------+
-| size    | Scaling ratio. Larger values will make a softer fade effect. Larger geometry requires higher values.   | integer | 45      |
-+---------+--------------------------------------------------------------------------------------------------------+---------+---------+
-| falloff | Fades away geometry as camera gets closer. Geometry full fades when parallel to camera.                | boolean | false   |
-+---------+--------------------------------------------------------------------------------------------------------+---------+---------+
++--------------+--------------------------------------------------------------------------------------------------------+---------+---------+
+| Name         | Description                                                                                            | Type    | Default |
++--------------+--------------------------------------------------------------------------------------------------------+---------+---------+
+| size         | Scaling ratio. Larger values will make a softer fade effect. Larger geometry requires higher values.   | integer | 45      |
++--------------+--------------------------------------------------------------------------------------------------------+---------+---------+
+| falloff      | Fades away geometry as camera gets closer. Geometry full fades when parallel to camera.                | boolean | false   |
++--------------+--------------------------------------------------------------------------------------------------------+---------+---------+
+| falloffDepth | The units at which geometry starts to fade.                                                            | float   | 300     |
++--------------+--------------------------------------------------------------------------------------------------------+---------+---------+
 
 Example usage.
 
@@ -48,6 +50,7 @@ Example usage.
             "soft_effect" : {
                 "size": 250,
                 "falloff" : false,
+                "falloffDepth": 5,
             }
         }
     }

files/shaders/compatibility/bs/nolighting.frag

@@ -38,6 +38,7 @@ uniform float alphaRef;
 uniform sampler2D opaqueDepthTex;
 uniform float particleSize;
 uniform bool particleFade;
+uniform float softFalloffDepth;
 #endif
 
 void main()
@@ -71,7 +72,8 @@ void main()
         far,
         texture2D(opaqueDepthTex, screenCoords).x,
         particleSize,
-        particleFade
+        particleFade,
+        softFalloffDepth
     );
 #endif
 

files/shaders/compatibility/objects.frag

@@ -98,6 +98,7 @@ varying vec3 passNormal;
 uniform sampler2D opaqueDepthTex;
 uniform float particleSize;
 uniform bool particleFade;
+uniform float softFalloffDepth;
 #endif
 
 #if @particleOcclusion
@@ -256,7 +257,8 @@ vec3 viewNormal = normalize(gl_NormalMatrix * normal);
         far,
         texture2D(opaqueDepthTex, screenCoords).x,
         particleSize,
-        particleFade
+        particleFade,
+        softFalloffDepth
     );
 #endif
 

files/shaders/lib/particle/soft.glsl

@@ -19,7 +19,8 @@ float calcSoftParticleFade(
     float far,
     float depth,
     float size,
-    bool fade
+    bool fade,
+    float softFalloffDepth
     )
 {
     float euclidianDepth = length(viewPos);
@@ -32,13 +33,12 @@ float calcSoftParticleFade(
     float falloff = size * falloffMultiplier;
     float delta = particleDepth - sceneDepth;
 
-    const float nearMult = 300.0;
     float viewBias = 1.0;
 
     if (fade)
     {
         float VdotN = dot(viewDir, viewNormal);
-        viewBias = abs(VdotN) * quickstep(euclidianDepth / nearMult) * (1.0 - pow(1.0 + VdotN, 1.3));
+        viewBias = abs(VdotN) * quickstep(euclidianDepth / softFalloffDepth) * (1.0 - pow(1.0 - abs(VdotN), 1.3));
     }
 
     const float shift = 0.845;