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Quadtree Tessellation

The Quadtree Tessellation system in Oceanology is designed to optimize the rendering of the infinite ocean while maintaining high performance and visual fidelity. Similar to other quadtree tessellation systems, this system dynamically adapts the level of detail of the water, ensuring a smooth experience for players. Below, you will find a detailed guide on how to configure and adjust the features of Quadtree Tessellation in Oceanology.

Overview of Quadtree Tessellation in Oceanology

Oceanology uses a Quadtree to generate the water plane mesh. The infinite ocean is not just a "flat water plane," as this would be very costly in terms of performance. Instead, Quadtree logic is used to optimize performance to a level acceptable for gameplay by creating level-of-detail meshes that adapt in real time to the camera's view.

The Quadtree in Oceanology uses the UHierarchicalInstancedStaticMeshComponent to construct the grid mesh. Outside the grid mesh, a "Far Mesh" component with a simple UStaticMeshComponent is used to render distant areas, reducing resource consumption.

Key Options and Settings in Quadtree Tessellation

  • Tile Size: Configures the size of each ocean grid. A higher value means fewer grids, but each is larger.

  • Extent in Tiles: Determines the number of grids in the ocean. More grids mean higher detail but also increase the performance cost.

  • Tessellation Factor: Adjusts the tessellation amount for each grid, affecting the quality of wave detail and water surface. A higher factor provides more vertices, which is useful for areas with many waves or pronounced details.

  • LODScale: Defines the radius size of each level of detail around the camera. Controls the distance at which grids start reducing their level of detail to optimize performance without compromising visual quality near the player.

  • Force Update Count: Sets the number of forced updates for the quadtree. This is useful when rapid adjustments are needed to change the mesh quality.

  • Use Far Mesh: When enabled, adds a simplified distant mesh to visually integrate the ocean with the horizon. This mesh uses a simpler material that matches the water mesh's color to provide a seamless transition.

Modes of Quadtree Tessellation

The Quadtree Tessellation system has three main modes that define the quality of the mesh used to render the ocean surface:

  • Game Ready (default): Default mode that offers good quality while maintaining optimal performance.

  • Simulation: Provides improved quality for simulations but uses more resources.

  • Render: Highest quality mode for video or cinematic rendering, with a high performance cost.

Level of Detail (LOD) and Tessellation

The level of detail (LOD) of the water is managed by traversing the quadtree each frame to generate an optimized set of visible grids on screen. The grids are reduced at each level of detail when possible, applying more density where it is most needed, such as close to the camera. Each level of detail has half the vertices of the previous level, which allows for smooth transitions between detail levels as the camera moves.

  • LODScale: Controls the radius at which grids begin to reduce their level of detail. This is essential for maintaining high quality in areas close to the player while reducing processing load in distant areas.

  • Tessellation Factor: Adjusts the vertex density for water grids. It is especially useful for enhancing wave quality and detail in water bodies like oceans and lakes.

Far Distance Mesh

The Far Distance Mesh is a simplified mesh located just below the base height of the ocean. This mesh helps avoid visible seams and provides a continuous appearance between the close ocean mesh and the horizon. You can configure the extent of this mesh using the Far Distance Mesh Extent property to define how far it extends in world units.

Tips for Effective Use

  • Balance Quality and Performance: Adjust the Tessellation Factor and LODScale simultaneously to find an appropriate balance between performance and visual quality. High quality should be maintained in areas near the player, and lower quality in the distance.

  • Use the Far Mesh: Make sure to use the Far Mesh to avoid visual discontinuities at the horizon. Configure a simple material that matches the water color for a seamless transition.

  • Mode Selection: Select the appropriate mode based on your project goal. Use Game Ready for most gameplay experiences, and Simulation or Render when higher visual quality is required.

Example: Setting Up Quadtree Tessellation in Oceanology

  1. Add Oceanology Infinite Ocean Actor

    • Start by dragging the BP_OceanologyInfiniteOcean actor into your scene.

  2. Configure Tile Size and Extents

    • In the details panel, set the Tile Size to 2400 and Extent in Tiles to 64x64. This will provide a large coverage area while maintaining efficient performance.

  3. Set Tessellation Factor

    • Adjust the Tessellation Factor to 6. This ensures a good balance between performance and quality, especially for areas with dynamic waves.

  4. Adjust LODScale

    • Set the LODScale to 1.0 to determine how quickly the level of detail will decrease as the camera moves away from the ocean.

  5. Enable Far Mesh

    • Tick the Use Far Mesh box and set Far Distance Mesh Extent to 200000. This helps fill the visual gap towards the horizon for a seamless ocean appearance.

  6. Select Quadtree Mode

    • Choose Game Ready mode for optimal performance during gameplay.

  7. Test in Play Mode

    • Enter play mode and move around the ocean to see how the tessellation and LOD adjust dynamically. Make further adjustments if necessary to maintain both visual quality and performance.

Summary

The Quadtree Tessellation in Oceanology provides an efficient way to handle the infinite ocean mesh, similar to other dynamic tessellation systems. By utilizing dynamic levels of detail and a simplified distant mesh, you can maintain a balance between visual quality and game performance. Configure the LODScale, Tessellation Factor, and Far Distance Mesh to create a stunning water surface without significantly affecting performance.

For further guidance, refer to our example scenes or join our Discord community for additional support and tips on how to get the most out of the Quadtree Tessellation system in Oceanology.