only lightmap updated tiles once they're visible

src/common/rendering/hwrenderer/data/hw_levelmesh.cpp

@@ -140,6 +140,12 @@ LevelMeshTileStats LevelMesh::GatherTilePixelStats()
 			stats.tiles.dirty++;
 			stats.pixels.dirty += area;
 		}
+		
+		if (tile.AlwaysUpdate)
+		{
+			stats.tiles.dirtyDynamic++;
+			stats.pixels.dirtyDynamic += area;
+		}
 	}
 	stats.tiles.total += Lightmap.Tiles.Size();
 	return stats;

src/common/rendering/hwrenderer/data/hw_levelmesh.h

@@ -250,7 +250,7 @@ struct LevelMeshTileStats
 {
 	struct Stats
 	{
-		uint32_t total = 0, dirty = 0;
+		uint32_t total = 0, dirty = 0, dirtyDynamic = 0;
 	};
 
 	Stats tiles, pixels;

src/playsim/a_dynlight.cpp

@@ -78,7 +78,11 @@ static void MarkTilesForUpdate(FLevelLocals * Level, const TArrayView<int> &tile
 	{
 		if(i >= 0)
 		{
-			Level->levelMesh->Lightmap.Tiles[i].NeedsUpdate = true;
+			auto &tile = Level->levelMesh->Lightmap.Tiles[i];
+			if(tile.AlwaysUpdate == 0 && !tile.NeedsUpdate)
+			{
+				tile.AlwaysUpdate = 3;
+			}
 		}
 	}
 }

src/rendering/hwrenderer/doom_levelmesh.cpp

@@ -75,15 +75,15 @@ ADD_STAT(lightmap)
 	int indexBufferUsed = levelMesh->FreeLists.Index.GetUsedSize();
 
 	out.Format(
-		"Surfaces: %u (awaiting updates: %u)\n"
-		"Surface pixel area to update: %u\n"
+		"Surfaces: %u (awaiting updates: %u static, %u dynamic)\n"
+		"Surface pixel area to update: %u static, %u dynamic\n"
 		"Surface pixel area: %u\nAtlas pixel area:   %u\n"
 		"Atlas efficiency: %.4f%%\n"
 		"Dynamic BLAS time: %2.3f ms\n"
 		"Level mesh process time: %2.3f ms\n"
 		"Level mesh index buffer: %d K used (%d%%)",
-		stats.tiles.total, stats.tiles.dirty,
-		stats.pixels.dirty,
+		stats.tiles.total, stats.tiles.dirty, stats.tiles.dirtyDynamic,
+		stats.pixels.dirty, stats.pixels.dirtyDynamic,
 		stats.pixels.total,
 		atlasPixelCount,
 		float(stats.pixels.total) / float(atlasPixelCount) * 100.0f,

src/rendering/hwrenderer/scene/hw_drawinfo.cpp

@@ -139,6 +139,7 @@ void HWDrawInfo::StartScene(FRenderViewpoint &parentvp, HWViewpointUniforms *uni
 	Coronas.Clear();
 	Fogballs.Clear();
 	VisibleTiles.Clear();
+	visibleDyn = 0;
 	vpIndex = 0;
 
 	// Fullbright information needs to be propagated from the main view.

src/rendering/hwrenderer/scene/hw_drawinfo.h

@@ -158,6 +158,7 @@ struct HWDrawInfo
 	TArray<AActor*> Coronas;
 	TArray<Fogball> Fogballs;
 	TArray<LightmapTile*> VisibleTiles;
+	unsigned visibleDyn;
 	uint64_t LastFrameTime = 0;
 
 	TArray<MissingTextureInfo> MissingUpperTextures;
@@ -243,8 +244,15 @@ public:
 		if (lm_always_update || tile->AlwaysUpdate == 2 || (tile->AlwaysUpdate == 1 && lm_dynamic))
 		{
 			tile->NeedsUpdate = true;
+			visibleDyn++;
 		}
-		else if (VisibleTiles.Size() >= unsigned(lm_max_updates))
+		else if(tile->AlwaysUpdate == 3 && lm_dynamic)
+		{
+			tile->AlwaysUpdate = 0;
+			tile->NeedsUpdate = true;
+			visibleDyn++;
+		}
+		else if ((VisibleTiles.Size() - visibleDyn) >= unsigned(lm_max_updates))
 		{
 			return;
 		}