Level Transitions

Level transitions are what I am calling the system that replaces most of the previous systems and logic used to determine what gets loads dynamically in a level. Specifically a component that is globally accessible called a LevelTransitionComponent (LTC).

The LTC manages Data Layers that are part of Unreal Engine 5’s World Partition system. LTC allows level designers to setup configurations for each map that define the following Data Layers:

  • Level: Additional terrain or geometry in the map to meet specific needs. This could come in the form of a wall that blocks access in a specific configuration while another configuration would have no wall and allow access to meet the needs of another configuration. Note: This does not replace destructibles in levels that players can interact with within a level. Destructibles still exist. (Probably talk about destructibles next week).
  • Theme: Global Lighting, Weather
  • Items: Item layouts specific to a configuration. Allows dynamic item layouts.
  • Enemies: Enemy layouts specific to a configuration. Allows dynamic enemy layouts.
NLT: Test Clip Configuration

Level designers may create any number of configurations for each number of players in a level.

Data layer transitions

Above is a clip from a test level of the data layers transitioning between unloaded, loading and activated.

NLT: Base

When a level is loaded, the LTC shows the loading screen, determines which configurations are valid for the level and the number of players. The LTC then uses a seeded stream to determine which configurations to load as needed. Once the configuration is chosen, the LTC replicates the needed information to any attached clients (for multiplayer) and waits for the clients to report that they have loaded the Data Layers needed for the chosen configuration. It’s necessary to know when all clients have loaded the configured data layers so that all clients can have their loading screen hidden at the same time.

NLT: Living Trees

LTC has other helper functions such as a function to load the next configuration and a function to reload the current configuration and Reload Current Configuration that are exposed to Blueprints.

NLT: Dead Trees

Below is a video showing the Nanite Lumen Test level in a very unfinished form. For this clip the NLT level was setup with 3 themes (Cloudy, Thunderstorm, and Dust Storm), and 3 level layers (blank, dead trees, and living trees). Using those layers the following configurations were made: Cloudy/Blank, Thunderstorm/Living Trees, and Dust Storm/Dead Trees. The clip shows Dawksin in a configuration that has a wall blocking him until he uses a trigger to cause LTC to load the next configuration. By the end of the short clip, Dawksin has gone through all 3 test configurations.

In a real level that players will be going through, they would be presented with a combination of themes, level layouts, enemy layouts and item layouts that would not repeat until all available combinations have been used at least once.

The clip is kind of a quick test of the LTC using real assets and it might not look very impressive, but it has helped iron out a lot of bugs.

Current known Issue: First level theme load causes shader compilation which delays the level from being lit even with sizable delays. Hopefully have a fix for this soon.