This package is used in conjunction with the main cluster-display package to control how your scene is rendered across multiple displays.
See the Cluster Display documentation for general information, installation, and use of Cluster Display.
Cluster Display Graphics depends on URP or HDRP 14.0.3 (Unity 2022.2 and above). Install either "Universal RP" or "High Definition RP" from the package manager.
Cluster Display Graphics features are enabled by adding an instance of the ClusterRenderer component to your scene. This component allows you to define a Projection Policy.
The camera frustum is divided into a rectangular grid. Learn more about Tiled Projections
The camera frustum is projected onto the specified geometry. Use this projection to generate a perspective-correct view on a curved display surface (e.g. LED wall).
Same as Mesh Warp, above, but provides better image quality if your displays are flat.
We call the pixel surface subsection rendered by each machine a tile. We describe the target pixel surface as a grid of displays, with the size expressed in tiles. For example, a 3x3 grid size would output to 9 displays. Note that for the time being, we assume displays all have the same dimensions and are arranged as a regular 2D grid without any gap.
We subdivide the viewport into tiles, based on the grid size. We index those tiles row by row, starting at the top left corner of the grid (tile index 0). The tile index is inferred from the Cluster Display state. Note that it is possible to manually take control of the tile index and the viewport subsection for debugging purposes.
In the figure below, we visualize a camera frustum sliced as a 2x2 grid; the frustum of the tileIndex = 0 slice is highlighted in blue.
Many effects compute a pixel's value based on its neighbors (think of blur for example). To allow for seamless tiling, we slightly expand the frustum/viewport, so that each pixel of the original viewport has access to its neighbors. Those additional pixels are cropped out of the final output after effects have been computed.
Some screen space computations need to happen at the scale of the global cluster output rather than in each machine's local screen space. We therefore introduce the notion of Cluster Space.
In the illustration below, we imagine a cloud is to be placed in screen space on a 2x2 grid. On the left, each machine places the cloud with respect to its local screen space coordinates. On the right, all machines place the cloud at the same place as the computation occurs in Cluster Space.
Above figure uses an icon from FreePik
In case the displays being used have bezels, those need to be taken into account to adjust the projection. Both values represent physical units (mm) and should not be confused with screen size (expressed in pixels).
The following effects do not require any adaptation to be Cluster Display compatible:
- Channel Mixer
- Film Grain (provided a tileable texture is used)
- Lift, Gamma, Gain
- Split Toning
- White Balance
- Tonemapping
- Color Curves
- Color Adjustments
- Shadows, Midtones, Highlights
- Fast Approximate Anti Aliasing (FXAA)
- Enhanced Subpixel Morphological Antialiasing (SMAA)
- MSAA
- Subsurface Scattering
The following effects rely on this package for Cluster Display support:
| Effect | Uses Overscan | Uses Cluster Display |
|---|---|---|
| Bloom | yes | - |
| Vignette | - | yes |
| Motion Blur | yes | - |
| Chromatic Aberration | - | yes |
| Depth of Field | yes | - |
| Lens Distortion | yes | yes |
| Temporal Anti Aliasing | yes | - |
| Ambient Occlusion | yes | - |
Note that for effects relying on overscan, there is a correlation between the amount of overscan and the maximal intensity of the effect before noticeable artefacts appear. A balance is to be found between the amount of overscan (which increases rendering cost) and the intensity of an effect according to an artistic intent.
Let's consider Bloom for example, in the capture below, bloom works with overscan:
However, if we use a high scatter value, artefacts become apparent despite overscan:
