Buildable Static Meshes

<font size=5 bold>WARNING: Building lots of these <u>will make your game lag.</u> These buildables do not use optimizations like instanced static meshes or abstract instances. I cannot use these optimizations because not all materials support them (defined by a build-time setting I cannot change).</font>

For decoration, consider using https://ficsit.app/mod/MoreDecorations or https://ficsit.app/mod/Factory_Prop_Mod instead.

Description

This mod adds buildable versions of any static mesh in the game, as well as mods. These buildables are unlocked by default, cost nothing to build and have a UI that allows choosing the materials to use for each material slot on the mesh. The UI remembers the last selected material slot as well as the search text, so you can simply close the UI at any moment to check what the static mesh looks like.

Note that different "things" may use the same static mesh, so you won't find separate buildables for each thing. For example, a Uranium Resource Node uses the static mesh of an Iron Resource Node but with different materials.

Note that this mod generates stuff dynamically, i.e. at runtime, based on what it finds. If you remove any other mod and/or game updates remove some static meshes and/or materials, any buildable static meshes in the world will be affected (removed static meshes will vanish, removed materials should revert to a fallback material).

Known bugs

- Meshes that don't have a collision box cannot be interacted with nor dismantled using vanilla methods. You may use SCIM and/or some mass dismantle mod to get rid of these uninteractable buildables. Worst comes to worst, uninstalling/disabling this mod (or the mod that added the mesh) then loading and saving your save will get rid of the uninteractable buildable.
- Multiplayer is completely untested, and most likely won't work (at the very least, the UI won't do anything for clients).

Intended use cases

- People (mainly mod developers) that want to see what static meshes and materials look like in-game (the materials we have in the Unreal Editor aren't accurate and sometimes look completely different)
- People who understand that spamming these buildables is bad for performance, but want to use a small amount of buildable static meshes with specific materials to decorate their factories, and none of the other factory props/decoration mods provide this functionality.

Technical details and performance notes

We find all static meshes and materials in the game and mods at runtime. For performance, we query the Asset Registry to get all assets of a certain type (fast), and then we use the Asset Manager's Streamable Manager to asynchronously load all the assets (slow, but doesn't block).

For static meshes, we have to generate buildables, build menu categories, building descriptors and building recipes. We use `FClassGenerator::GenerateSimpleClass` from SML to achieve this. We also store all the building recipes in a schematic unlock, so that we can make the recipes available later.

To display the materials in the UI, we initially tried to make a Slate brush out of the materials. But this doesn't work properly for materials in the surface domain, the kind used by static meshes... So, we had to improvise:

1. Place a "photo booth" somewhere (0, 0, 0) with a sample mesh (a sphere), a light and a camera.
2. Tell the sphere to "dress up" with whatever surface material we want to make a preview out of.
3. Tell the camera (actually, its Scene Capture 2D component) to take a picture and save it to a render target.
4. Create a dynamic material instance (of a material that inverts alpha) and use the render target as input.
5. Make a Slate brush using that material instance, which is basically a picture of the dressed-up sphere.
6. When we're done, get rid of the photo booth.

This process is surprisingly fast, and is only done once per world load (the photo booth needs to be in a world). For non-surface materials, we still make a Slate brush directly, as it usually works better (e.g. for UI materials).

The main reason why these buildables do not use ISMs (Instanced Static Meshes) is because not all materials support ISMs, and this mod is meant to allow visualizing any material on any mesh.