Support for radial fog (feature #4708)

CHANGELOG.md

@@ -225,6 +225,7 @@
     Feature #4544: Actors movement deceleration
     Feature #4673: Weapon sheathing
     Feature #4675: Support for NiRollController
+    Feature #4708: Radial fog support
     Feature #4730: Native animated containers support
     Feature #4784: Launcher: Duplicate Content Lists
     Feature #4812: Support NiSwitchNode

apps/opencs/model/world/data.cpp

@@ -82,6 +82,7 @@ CSMWorld::Data::Data (ToUTF8::FromType encoding, bool fsStrict, const Files::Pat
     defines["forcePPL"] = "0"; // Don't force per-pixel lighting
     defines["clamp"] = "1"; // Clamp lighting
     defines["preLightEnv"] = "0"; // Apply environment maps after lighting like Morrowind
+    defines["radialFog"] = "0";
     for (const auto& define : shadowDefines)
         defines[define.first] = define.second;
     mResourceSystem->getSceneManager()->getShaderManager().setGlobalDefines(defines);

apps/openmw/mwrender/renderingmanager.cpp

@@ -217,7 +217,9 @@ namespace MWRender
     {
         resourceSystem->getSceneManager()->setParticleSystemMask(SceneUtil::Mask_ParticleSystem);
         resourceSystem->getSceneManager()->setShaderPath(resourcePath + "/shaders");
-        resourceSystem->getSceneManager()->setForceShaders(Settings::Manager::getBool("force shaders", "Shaders") || Settings::Manager::getBool("enable shadows", "Shadows")); // Shadows have problems with fixed-function mode
+        // Shadows and radial fog have problems with fixed-function mode
+        bool forceShaders = Settings::Manager::getBool("radial fog", "Shaders") || Settings::Manager::getBool("force shaders", "Shaders") || Settings::Manager::getBool("enable shadows", "Shadows");
+        resourceSystem->getSceneManager()->setForceShaders(forceShaders);
         // FIXME: calling dummy method because terrain needs to know whether lighting is clamped
         resourceSystem->getSceneManager()->setClampLighting(Settings::Manager::getBool("clamp lighting", "Shaders"));
         resourceSystem->getSceneManager()->setAutoUseNormalMaps(Settings::Manager::getBool("auto use object normal maps", "Shaders"));
@@ -254,6 +256,7 @@ namespace MWRender
         globalDefines["forcePPL"] = Settings::Manager::getBool("force per pixel lighting", "Shaders") ? "1" : "0";
         globalDefines["clamp"] = Settings::Manager::getBool("clamp lighting", "Shaders") ? "1" : "0";
         globalDefines["preLightEnv"] = Settings::Manager::getBool("apply lighting to environment maps", "Shaders") ? "1" : "0";
+        globalDefines["radialFog"] = Settings::Manager::getBool("radial fog", "Shaders") ? "1" : "0";
 
         // It is unnecessary to stop/start the viewer as no frames are being rendered yet.
         mResourceSystem->getSceneManager()->getShaderManager().setGlobalDefines(globalDefines);

docs/source/reference/modding/settings/shaders.rst

@@ -135,3 +135,14 @@ apply lighting to environment maps
 Normally environment map reflections aren't affected by lighting, which makes environment-mapped (and thus bump-mapped objects) glow in the dark.
 Morrowind Code Patch includes an option to remedy that by doing environment-mapping before applying lighting, this is the equivalent of that option.
 Affected objects will use shaders.
+
+radial fog
+----------
+
+:Type:		boolean
+:Range:		True/False
+:Default:	False
+
+By default, the fog becomes thicker proportionally to your distance from the clipping plane set at the clipping distance, which causes distortion at the edges of the screen.
+This setting makes the fog use the actual eye point distance (or so called Euclidean distance) to calculate the fog, which makes the fog look less artificial, especially if you have a wide FOV.
+Note that the rendering will act as if you have 'force shaders' option enabled with this on, which means that shaders will be used to render all objects and the terrain.

files/settings-default.cfg

@@ -350,6 +350,10 @@ terrain specular map pattern = _diffusespec
 # Affected objects use shaders.
 apply lighting to environment maps = false
 
+# Determine fog intensity based on the distance from the eye point.
+# This makes fogging independent from the viewing angle. Shaders will be used to render all objects.
+radial fog = false
+
 [Input]
 
 # Capture control of the cursor prevent movement outside the window.

files/shaders/objects_fragment.glsl

@@ -49,7 +49,8 @@ uniform vec2 envMapLumaBias;
 uniform mat2 bumpMapMatrix;
 #endif
 
-varying float depth;
+varying float euclideanDepth;
+varying float linearDepth;
 
 #define PER_PIXEL_LIGHTING (@normalMap || @forcePPL)
 
@@ -146,7 +147,7 @@ void main()
 
 #endif
 
-    float shadowing = unshadowedLightRatio(depth);
+    float shadowing = unshadowedLightRatio(linearDepth);
 
 #if !PER_PIXEL_LIGHTING
 
@@ -178,8 +179,11 @@ void main()
 #endif
 
     gl_FragData[0].xyz += getSpecular(normalize(viewNormal), normalize(passViewPos.xyz), shininess, matSpec) * shadowing;
-
-    float fogValue = clamp((depth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
+#if @radialFog
+    float fogValue = clamp((euclideanDepth - 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
     gl_FragData[0].xyz = mix(gl_FragData[0].xyz, gl_Fog.color.xyz, fogValue);
 
     applyShadowDebugOverlay();

files/shaders/objects_vertex.glsl

@@ -37,7 +37,8 @@ varying vec2 bumpMapUV;
 varying vec2 specularMapUV;
 #endif
 
-varying float depth;
+varying float euclideanDepth;
+varying float linearDepth;
 
 #define PER_PIXEL_LIGHTING (@normalMap || @forcePPL)
 
@@ -57,10 +58,12 @@ varying vec3 passNormal;
 void main(void)
 {
     gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
-    depth = gl_Position.z;
 
     vec4 viewPos = (gl_ModelViewMatrix * gl_Vertex);
     gl_ClipVertex = viewPos;
+    euclideanDepth = length(viewPos.xyz);
+    linearDepth = gl_Position.z;
+
     vec3 viewNormal = normalize((gl_NormalMatrix * gl_Normal).xyz);
 
 #if @envMap

files/shaders/terrain_fragment.glsl

@@ -12,7 +12,8 @@ uniform sampler2D normalMap;
 uniform sampler2D blendMap;
 #endif
 
-varying float depth;
+varying float euclideanDepth;
+varying float linearDepth;
 
 #define PER_PIXEL_LIGHTING (@normalMap || @forcePPL)
 
@@ -66,7 +67,7 @@ void main()
     gl_FragData[0].a *= texture2D(blendMap, blendMapUV).a;
 #endif
 
-    float shadowing = unshadowedLightRatio(depth);
+    float shadowing = unshadowedLightRatio(linearDepth);
 
 #if !PER_PIXEL_LIGHTING
 
@@ -90,7 +91,11 @@ void main()
 
     gl_FragData[0].xyz += getSpecular(normalize(viewNormal), normalize(passViewPos), shininess, matSpec) * shadowing;
 
-    float fogValue = clamp((depth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
+#if @radialFog
+    float fogValue = clamp((euclideanDepth - 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
     gl_FragData[0].xyz = mix(gl_FragData[0].xyz, gl_Fog.color.xyz, fogValue);
 
     applyShadowDebugOverlay();

files/shaders/terrain_vertex.glsl

@@ -1,7 +1,8 @@
 #version 120
 
 varying vec2 uv;
-varying float depth;
+varying float euclideanDepth;
+varying float linearDepth;
 
 #define PER_PIXEL_LIGHTING (@normalMap || @forcePPL)
 
@@ -21,10 +22,11 @@ varying vec3 passNormal;
 void main(void)
 {
     gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
-    depth = gl_Position.z;
 
     vec4 viewPos = (gl_ModelViewMatrix * gl_Vertex);
     gl_ClipVertex = viewPos;
+    euclideanDepth = length(viewPos.xyz);
+    linearDepth = gl_Position.z;
     
     vec3 viewNormal = normalize((gl_NormalMatrix * gl_Normal).xyz);
 

files/shaders/water_fragment.glsl

@@ -124,7 +124,7 @@ vec2 normalCoords(vec2 uv, float scale, float speed, float time, float timer1, f
 
 varying vec3 screenCoordsPassthrough;
 varying vec4 position;
-varying float depthPassthrough;
+varying float linearDepth;
 
 uniform sampler2D normalMap;
 
@@ -160,7 +160,7 @@ void main(void)
     vec2 UV = worldPos.xy / (8192.0*5.0) * 3.0;
     UV.y *= -1.0;
 
-    float shadow = unshadowedLightRatio(depthPassthrough);
+    float shadow = unshadowedLightRatio(linearDepth);
 
     vec2 screenCoords = screenCoordsPassthrough.xy / screenCoordsPassthrough.z;
     screenCoords.y = (1.0-screenCoords.y);
@@ -203,11 +203,17 @@ void main(void)
     float ior = (cameraPos.z>0.0)?(1.333/1.0):(1.0/1.333); // air to water; water to air
     float fresnel = clamp(fresnel_dielectric(vVec, normal, ior), 0.0, 1.0);
 
+#if @radialFog
+    float radialDepth = distance(position.xyz, cameraPos);
+    float radialize = radialDepth / linearDepth;
+#else
+    float radialize = 1.0;
+#endif
     vec2 screenCoordsOffset = normal.xy * REFL_BUMP;
 #if REFRACTION
-    float depthSample = linearizeDepth(texture2D(refractionDepthMap,screenCoords).x);
-    float depthSampleDistorted = linearizeDepth(texture2D(refractionDepthMap,screenCoords-screenCoordsOffset).x);
-    float surfaceDepth = linearizeDepth(gl_FragCoord.z);
+    float depthSample = linearizeDepth(texture2D(refractionDepthMap,screenCoords).x) * radialize;
+    float depthSampleDistorted = linearizeDepth(texture2D(refractionDepthMap,screenCoords-screenCoordsOffset).x) * radialize;
+    float surfaceDepth = linearizeDepth(gl_FragCoord.z) * radialize;
     float realWaterDepth = depthSample - surfaceDepth;  // undistorted water depth in view direction, independent of frustum
     screenCoordsOffset *= clamp(realWaterDepth / BUMP_SUPPRESS_DEPTH,0,1);
 #endif
@@ -246,7 +252,11 @@ void main(void)
 #endif
 
     // fog
-    float fogValue = clamp((depthPassthrough - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
+#if @radialFog
+    float fogValue = clamp((radialDepth - 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
     gl_FragData[0].xyz = mix(gl_FragData[0].xyz,  gl_Fog.color.xyz,  fogValue);
 
     applyShadowDebugOverlay();

files/shaders/water_vertex.glsl

@@ -2,7 +2,7 @@
     
 varying vec3  screenCoordsPassthrough;
 varying vec4  position;
-varying float  depthPassthrough;
+varying float linearDepth;
 
 #include "shadows_vertex.glsl"
 
@@ -20,7 +20,7 @@ void main(void)
 
     position = gl_Vertex;
 
-    depthPassthrough = gl_Position.z;
+    linearDepth = gl_Position.z;
 
     setupShadowCoords(gl_ModelViewMatrix * gl_Vertex, normalize((gl_NormalMatrix * gl_Normal).xyz));
 }