viewer#2780 Speed up terrain loading on teleport

Terrain was arriving and processing too late resulting in issues like
"Lower terrain material incorrectly shown momentarily"

Author: akleshchev

indra/newview/llappviewer.cpp

@@ -4968,6 +4968,20 @@ void LLAppViewer::idle()
 
     if (gTeleportDisplay)
     {
+        if (gAgent.getTeleportState() == LLAgent::TELEPORT_ARRIVING)
+        {
+            // Teleported, but waiting for things to load, start processing surface data
+            {
+                LL_RECORD_BLOCK_TIME(FTM_NETWORK);
+                gVLManager.unpackData();
+            }
+            {
+                LL_RECORD_BLOCK_TIME(FTM_REGION_UPDATE);
+                const F32 max_region_update_time = .001f; // 1ms
+                LLWorld::getInstance()->updateRegions(max_region_update_time);
+            }
+        }
+
         return;
     }
 

indra/newview/llviewermessage.cpp

@@ -3197,7 +3197,8 @@ void send_agent_update(bool force_send, bool send_reliable)
     LL_PROFILE_ZONE_SCOPED;
     llassert(!gCubeSnapshot);
 
-    if (gAgent.getTeleportState() != LLAgent::TELEPORT_NONE)
+    if (gAgent.getTeleportState() != LLAgent::TELEPORT_NONE
+        && gAgent.getTeleportState() != LLAgent::TELEPORT_ARRIVING)
     {
         // We don't care if they want to send an agent update, they're not allowed
         // until the target simulator is ready to receive them

indra/newview/llviewertexturelist.cpp

@@ -30,6 +30,7 @@
 
 #include "llviewertexturelist.h"
 
+#include "llagent.h"
 #include "llgl.h" // fot gathering stats from GL
 #include "llimagegl.h"
 #include "llimagebmp.h"
@@ -844,10 +845,19 @@ void LLViewerTextureList::updateImages(F32 max_time)
             clearFetchingRequests();
             gPipeline.clearRebuildGroups();
             cleared = true;
+            return;
         }
-        return;
+        // ARRIVING is a delay to let things decode, cache and process,
+        // so process textures like normal despite gTeleportDisplay
+        if (gAgent.getTeleportState() != LLAgent::TELEPORT_ARRIVING)
+        {
+            return;
+        }
+    }
+    else
+    {
+        cleared = false;
     }
-    cleared = false;
 
     LLAppViewer::getTextureFetch()->setTextureBandwidth((F32)LLTrace::get_frame_recording().getPeriodMeanPerSec(LLStatViewer::TEXTURE_NETWORK_DATA_RECEIVED).value());