Changelog

1.1.0

A heavy crash costs far less on the game thread. On the machine we measured, no frame of a heavy crash now spends more than about 1.3 ms on Crushform’s game-thread work, down from several milliseconds in the crash frame.

Damaged cars cost far less to draw, and a project can now limit how many of them draw their damage. On a Mali-G76 GPU under OpenGL ES 3.1, at its top clock, the slot of a damaged body went from about 80 ms a frame to about 4 ms. We did not measure the gain on a desktop GPU.

New:

• Collision work off the game thread. A torn part’s cut, a dented body’s rebuild and a torn part’s hull run on a worker. UCFSettings::CollisionDeferFrames (1), or Crushform.Collision.DeferFrames, takes 0 or 1. At 1 the body’s rebuild and cut are on the body before the next frame’s physics. 0 builds everything in the frame of the hit, as in 1.0.0.
• A project switch for collision that follows dents. UCFSettings::bDeformCollision (on), or Crushform.Collision.Deform. Off wins over every profile, so a device profile can turn it off for weak devices.
• Glass shards are a Niagara system. The default is UCFSettings::DefaultGlassShardSystem, and UCFGlassDefinition::ShardSystem sets another one for a definition. They no longer use the debris pool or its limit. Crushform.Glass.ShardScale sets the share of shards thrown, and Crushform.Glass.MaxLiveShards (512) caps those alive at once.
• Panes that break together start a frame apart. Crushform.Glass.ShardSystemsPerFrame (1) sets how many shard systems start in one frame. 0 is no limit.
• Impact sounds start a few at a time. UCFImpactFeedbackSettings::MaxSoundsPerFrame (2) sets how many start in one frame. The rest wait up to UCFImpactFeedbackSettings::SoundQueueSeconds (0.15 s), strongest first, and are then dropped.
• Named trace scopes along the whole hit path. Performance lists them.
• Draw limits for dents and for dirt, set apart. Dents and scratches: UCFSettings::DentCullDistance and UCFSettings::MaxDentedBodies, or Crushform.Dents.CullDistance and Crushform.Dents.MaxBodies. Dirt on the body and the wheels: UCFSettings::DirtCullDistance and UCFSettings::MaxDirtyBodies, or Crushform.Dirt.CullDistance and Crushform.Dirt.MaxBodies. The nearest bodies draw first, those on screen before those off it. All four default to 0, no limit, and a device profile can set them per device.
• Generated LODs on the Sedan. Its static meshes have three more LODs, down to about a tenth of the triangles, and the whole car changes LOD at one distance. Nanite draws the meshes that use it as before; a platform without Nanite draws these LODs, and so does the glass everywhere.
• A simple LOD on the aspen. SM_CF_Tree, 804 triangles, is LOD1 of the tree in BP_CF_Tree. Android and iOS draw it through the mesh’s minimum LOD; other platforms keep the full aspen.
• Android and iOS. Every runtime module now allows both as targets, alongside Win64, Linux and Mac. Android was run on a Mali-G76 under OpenGL ES 3.1; iOS has not been built or run yet. On a phone, use the draw limits above and turn off UCFSettings::bDeformCollision.

Changed:

• Deformation reads less. A vertex is evaluated once in a shader invocation, with about 11 atlas reads instead of 32. A body with no dent and no scratch reads nothing in the vertex stage.
• Dirt reads less. A pixel takes 2 filtered reads instead of 8. RT_CF_DirtAtlas and RT_CF_DirtFreshAtlas now read bilinear; a project with its own dirt atlases sets their filter to bilinear too.
• CF_DirtBlend, CF_DirtAmount and CF_DirtFresh take the atlas’s sampler. A project’s own Custom node that calls them passes it as the next argument after the atlas.
• Scratch lines are the same lines at every distance. The shader now works them out instead of thresholding a texture, so they no longer flicker or break up and none appear only up close. A far line grows fainter, and further away the lines blend into an even lightening. UCFProfile::MaxScratch now defaults to 0.033 instead of 0.1, about a third of the lines on a wreck.

Changed behaviour, at the default settings:

• A hinged part starts to swing or comes off the frame after the crash, not in it.
• A part that comes off waits for the body’s collision to be cut around its place: a frame, or two when another collision build was running. Until then it stays in place or keeps swinging on its hinge.

Set Crushform.Collision.DeferFrames to 0 to get the old timing of both back.

Past a dirt limit a body draws clean and its dirt stands still on that machine: it neither gathers nor fades until the body is shown again. A wash, a fill or added dirt still applies. Past a dent limit a body draws whole; its lattice, collision, replication and damage events go on. With the limits at 0, the default, none of this happens.

1.0.0

First public release.