Implement SunDiscSunsetColor, fade the sun during sunrise & sunset

apps/openmw/mwrender/sky.cpp

@@ -402,6 +402,13 @@ public:
         destroySunGlare();
     }
 
+    void setColor(const osg::Vec4f& color)
+    {
+        mUpdater->mColor.r() = color.r();
+        mUpdater->mColor.g() = color.g();
+        mUpdater->mColor.b() = color.b();
+    }
+
     virtual void adjustTransparency(const float ratio)
     {
         mUpdater->mColor.a() = ratio;
@@ -576,7 +583,7 @@ private:
         osg::Vec4f mColor;
 
         Updater()
-            : mColor(1.f, 1.f, 1.f, 1.0f)
+            : mColor(1.f, 1.f, 1.f, 1.f)
         {
         }
 
@@ -588,7 +595,8 @@ private:
         virtual void apply(osg::StateSet* stateset, osg::NodeVisitor*)
         {
             osg::Material* mat = static_cast<osg::Material*>(stateset->getAttribute(osg::StateAttribute::MATERIAL));
-            mat->setDiffuse(osg::Material::FRONT_AND_BACK, mColor);
+            mat->setDiffuse(osg::Material::FRONT_AND_BACK, osg::Vec4f(0,0,0,mColor.a()));
+            mat->setEmission(osg::Material::FRONT_AND_BACK, osg::Vec4f(mColor.r(), mColor.g(), mColor.b(), 1));
         }
     };
 
@@ -1464,15 +1472,8 @@ void SkyManager::setWeather(const WeatherResult& weather)
     mMasser->adjustTransparency(weather.mGlareView);
     mSecunda->adjustTransparency(weather.mGlareView);
 
-    /*
-    float timeofday_angle = std::abs(mSun->getPosition().z/mSunGlare->getPosition().length());
-    float strength;
-    if (timeofday_angle <= 0.44)
-        strength = timeofday_angle/0.44f;
-    else
-        strength = 1.f;
-    */
-    mSun->adjustTransparency(weather.mGlareView);
+    mSun->setColor(weather.mSunDiscColor);
+    mSun->adjustTransparency(weather.mGlareView * weather.mSunDiscColor.a());
 
     float nextStarsOpacity = weather.mNightFade * weather.mGlareView;
     if(weather.mNight && mStarsOpacity != nextStarsOpacity)

apps/openmw/mwrender/sky.hpp

@@ -48,8 +48,10 @@ namespace MWRender
 
         osg::Vec4f mSkyColor;
 
+        // sun light color
         osg::Vec4f mSunColor;
 
+        // alpha is the sun transparency
         osg::Vec4f mSunDiscColor;
 
         float mFogDepth;

apps/openmw/mwworld/weather.cpp

@@ -432,6 +432,7 @@ WeatherManager::WeatherManager(MWRender::RenderingManager& rendering, const MWWo
     , mSunsetTime(fallback.getFallbackFloat("Weather_Sunset_Time"))
     , mSunriseDuration(fallback.getFallbackFloat("Weather_Sunrise_Duration"))
     , mSunsetDuration(fallback.getFallbackFloat("Weather_Sunset_Duration"))
+    , mSunPreSunsetTime(fallback.getFallbackFloat("Weather_Sun_Pre-Sunset_Time"))
     , mNightStart(mSunsetTime + mSunsetDuration)
     , mNightEnd(mSunriseTime - 0.5f)
     , mDayStart(mSunriseTime + mSunriseDuration)
@@ -966,7 +967,6 @@ inline void WeatherManager::calculateResult(const int weatherID, const float gam
     mResult.mAmbientLoopSoundID = current.mAmbientLoopSoundID;
     mResult.mAmbientSoundVolume = 1.f;
     mResult.mEffectFade = 1.f;
-    mResult.mSunColor = current.mSunDiscSunsetColor;
 
     mResult.mIsStorm = current.mIsStorm;
 
@@ -980,6 +980,7 @@ inline void WeatherManager::calculateResult(const int weatherID, const float gam
 
     mResult.mFogDepth = mResult.mNight ? current.mLandFogNightDepth : current.mLandFogDayDepth;
 
+    // TODO: use pre/post sunset/sunrise time values in [Weather] section
     // night
     if (gameHour <= mNightEnd || gameHour >= mNightStart + 1)
     {
@@ -1050,6 +1051,36 @@ inline void WeatherManager::calculateResult(const int weatherID, const float gam
             mResult.mNightFade = factor;
         }
     }
+
+    if (gameHour >= mSunsetTime - mSunPreSunsetTime)
+    {
+        float factor = (gameHour - (mSunsetTime - mSunPreSunsetTime)) / mSunPreSunsetTime;
+        factor = std::min(1.f, factor);
+        mResult.mSunDiscColor = lerp(osg::Vec4f(1,1,1,1), current.mSunDiscSunsetColor, factor);
+        // The SunDiscSunsetColor in the INI isn't exactly the resulting color on screen, most likely because
+        // MW applied the color to the ambient term as well. After the ambient and emissive terms are added together, the fixed pipeline
+        // would then clamp the total lighting to (1,1,1). A noticable change in color tone can be observed when only one of the color components gets clamped.
+        // Unfortunately that means we can't use the INI color as is, have to replicate the above nonsense.
+        mResult.mSunDiscColor = mResult.mSunDiscColor + osg::componentMultiply(mResult.mSunDiscColor, mResult.mAmbientColor);
+        for (int i=0; i<3; ++i)
+            mResult.mSunDiscColor[i] = std::min(1.f, mResult.mSunDiscColor[i]);
+    }
+    else
+        mResult.mSunDiscColor = osg::Vec4f(1,1,1,1);
+
+    if (gameHour >= mSunsetTime)
+    {
+        float fade = std::min(1.f, (gameHour - mSunsetTime) / 2.f);
+        fade = fade*fade;
+        mResult.mSunDiscColor.a() = 1.f - fade;
+    }
+    else if (gameHour >= mSunriseTime && gameHour <= mSunriseTime + 1)
+    {
+        mResult.mSunDiscColor.a() = gameHour - mSunriseTime;
+    }
+    else
+        mResult.mSunDiscColor.a() = 1;
+
 }
 
 inline void WeatherManager::calculateTransitionResult(const float factor, const float gameHour)

apps/openmw/mwworld/weather.hpp

@@ -75,7 +75,7 @@ namespace MWWorld
         float mLandFogDayDepth;
         float mLandFogNightDepth;
 
-        // Color modulation for the sun itself during sunset (not completely sure)
+        // Color modulation for the sun itself during sunset
         osg::Vec4f mSunDiscSunsetColor;
 
         // Used by scripts to animate signs, etc based on the wind (GetWindSpeed)
@@ -242,12 +242,7 @@ namespace MWWorld
         float mSunsetTime;
         float mSunriseDuration;
         float mSunsetDuration;
-        // Some useful values
-        /* TODO: Use pre-sunrise_time, pre-sunset_time,
-         * post-sunrise_time, and post-sunset_time to better
-         * describe sunrise/sunset time.
-         * These values are fallbacks attached to weather.
-         */
+        float mSunPreSunsetTime;
         float mNightStart;
         float mNightEnd;
         float mDayStart;