SL-9793 EEP Clouds vanish and reappear abruptly if one of textures is not set

1 files changed, 26 insertions, 1 deletions

diff --git a/indra/llinventory/llsettingssky.cpp b/indra/llinventory/llsettingssky.cpp
index 088c183f70..9d839e88d0 100644
--- a/indra/llinventory/llsettingssky.cpp
+++ b/indra/llinventory/llsettingssky.cpp
@@ -459,11 +459,35 @@ void LLSettingsSky::blend(const LLSettingsBase::ptr_t &end, F64 blendf)
             }
         }
 
+        LLUUID cloud_noise_id = getCloudNoiseTextureId();
+        LLUUID cloud_noise_id_next = other->getCloudNoiseTextureId();
+        F64 cloud_shadow = 0;
+        if (!cloud_noise_id.isNull() && cloud_noise_id_next.isNull())
+        {
+            // If there is no cloud texture in destination, reduce coverage to imitate disappearance
+            // See LLDrawPoolWLSky::renderSkyClouds... we don't blend present texture with null
+            // Note: Probably can be done by shader
+            cloud_shadow = lerp(mSettings[SETTING_CLOUD_SHADOW].asReal(), (F64)0.f, blendf);
+            cloud_noise_id_next = cloud_noise_id;
+        }
+        else if (cloud_noise_id.isNull() && !cloud_noise_id_next.isNull())
+        {
+            // Source has no cloud texture, reduce initial coverage to imitate appearance
+            // use same texture as destination
+            cloud_shadow = lerp((F64)0.f, other->mSettings[SETTING_CLOUD_SHADOW].asReal(), blendf);
+            setCloudNoiseTextureId(cloud_noise_id_next);
+        }
+        else
+        {
+            cloud_shadow = lerp(mSettings[SETTING_CLOUD_SHADOW].asReal(), other->mSettings[SETTING_CLOUD_SHADOW].asReal(), blendf);
+        }
+
         LLSD blenddata = interpolateSDMap(mSettings, other->mSettings, other->getParameterMap(), blendf);
+        blenddata[SETTING_CLOUD_SHADOW] = LLSD::Real(cloud_shadow);
         replaceSettings(blenddata);
         mNextSunTextureId = other->getSunTextureId();
         mNextMoonTextureId = other->getMoonTextureId();
-        mNextCloudTextureId = other->getCloudNoiseTextureId();
+        mNextCloudTextureId = cloud_noise_id_next;
         mNextBloomTextureId = other->getBloomTextureId();
         mNextRainbowTextureId = other->getRainbowTextureId();
         mNextHaloTextureId = other->getHaloTextureId();
@@ -486,6 +510,7 @@ LLSettingsSky::stringset_t LLSettingsSky::getSkipInterpolateKeys() const
         skipSet.insert(SETTING_RAYLEIGH_CONFIG);
         skipSet.insert(SETTING_MIE_CONFIG);
         skipSet.insert(SETTING_ABSORPTION_CONFIG);
+        skipSet.insert(SETTING_CLOUD_SHADOW);
     }
 
     return skipSet;