CHexamaker

Overview

UCHexamaker is the hexagonal generation engine. It manages async tile computation, probabilistic mesh selection, multi-criteria filtering, and UHierarchicalInstancedStaticMeshComponent creation/removal. It inherits from UObject and implements ICCell and ICSingleDoRun.

Build Pipeline

Name	Description
buildASync	Entry point called by the spawner. Runs `drawHexa` async then `updateISM_sync` on the game thread
wantDraw	Checks if a new draw is needed: room state, pawn movement, queue status
drawHexa	Computes the tile grid around the pawn, runs `calculateTile` in `ParallelFor`, enqueues batches
updateISM_sync	Dequeues a batch, creates ISMs, removes old ones, broadcasts delegates

// buildASync is the main entry point, called each tick by ACHexaSpawner:
hexamaker->buildASync(singleDoRun, pawnX, pawnY);

// Internally:
// 1. wantDraw() checks if a new pass is needed
// 2. drawHexa() computes the UV grid, runs calculateTile() in ParallelFor
// 3. Results are queued as FCHexaDataQueue
// 4. updateISM_sync() dequeues and creates ISMs on the game thread

Tile Calculation

Name	Description
calculateTile	Computes a tile: probabilistic mesh selection, Z position, jitter, rotation, scale, filtering
bannedLocationCandidatToAdd	Checks if the position is inside a banned area
worldmakerCandidatToAdd	Checks altitude, slope, slope alignment via `WorldUtility`
roomMakerCandidatToAdd	Checks room type (ROOM/CORRIDOR/WALL) and distances

// calculateTile applies filters in this order:
// 1. Check enable and existing ISM
// 2. Convert coordinates → pixel
// 3. Biome noise filter (biomeSelectLowerBound/UpperBound)
// 4. Probabilistic mesh selection (meshProbaRHArray)
// 5. Rotation calculation (random if rotate=true)
// 6. Scale calculation (random between minScalePercent/maxScalePercent)
// 7. Jitter calculation (random between minJitterForce/maxJitterForce × tileSize)
// 8. Banned area filter (bannedLocationCandidatToAdd)
// 9. Worldmaker filter: altitude (withBound), slope (withNormal), alignment (alignToSlope)
// 10. Room filter: room type, distance to center/edge

ISM Management

Name	Description
proceedIsm	Prepares transform batches per mesh index for ISM creation
updateISM_sync	Creates `UCHierarchicalInstancedStaticMeshComponent`, configures shadow/collision/cull, assigns instances
removeTile (static)	Removes ISM instances by UV coordinates
removeTile (location)	Removes the closest tile to a world position

// ISM creation in updateISM_sync:
// For each mesh index, a UCHierarchicalInstancedStaticMeshComponent is created.
// Configuration applied: shadow, collision, cull distance, ghost material.
// Instances are added in batch via AddInstances().
// The index handler (FCIndexHandler) maintains the UV ↔ instance mapping.

// Tile removal:
UCHexamaker::removeTile(tileArray);           // by FCHexaMakerTile array
UCHexamaker::removeTile(ismIndexArrayMap);    // by ISM → UV index map
hexamaker->removeTile(FVector2D(x, y));       // by world position
hexamaker->removeTile(FVector2D(x, y), ism);  // by world position + specific ISM

Ghost Mode

Each group of layers generates two hexamakers: one normal and one ghost. The ghost uses a transparent material (MAT_CdryxGhostEffect) applied to all meshes, and inverts the banned area logic (displays only inside banned areas).

UCHierarchicalInstancedStaticMeshComponent

Extension of UHierarchicalInstancedStaticMeshComponent with an integrated FCIndexHandler for instance tracking.

Name	Description
indexHandler	Maintains the bidirectional mapping between UV coordinates and ISM instance indices

FCIndexHandler

Index manager for ISM instance tracking. Listens to OnInstanceIndexUpdated events to maintain consistency during additions/removals.

Name	Description
mapIndexToInstanceMap	UV → instance map (find instance number from a UV index)
mapInstanceToIndexMap	Instance → UV map (find UV index from an instance number)
assignIndexWithInstance	Associates an array of UV indices with an array of instance indices
onInstanceIndexUpdatedHandler	ISM callback: updates maps on Relocated/Removed/Cleared/Destroyed

// FCIndexHandler is created automatically by UCHierarchicalInstancedStaticMeshComponent.
// It listens to FInstancedStaticMeshDelegates::OnInstanceIndexUpdated.

// Find the ISM instance from UV coordinates:
if (int32* instance = chISM->indexHandler.mapIndexToInstanceMap.Find(uvIndex)) {
    // *instance is the instance number in the ISM
}

// Find UV coordinates from an instance number:
if (FCUVIndex* uvIdx = chISM->indexHandler.mapInstanceToIndexMap.Find(instanceId)) {
    // *uvIdx contains the (u, v) coordinates
}

FCHexaMakerTile

Tile structure inheriting from FCTile (CCOREUMODULE). Stores the computed placement data for a cell.

Name	Description
meshRotation	Computed mesh rotation
meshPosition	Computed world position (with jitter and Z)
meshScale	Computed scale
key	UV coordinates of the tile (`FCUVIndex`)
meshIdxInHexaMakerStruct	Index of the selected mesh in `meshProbaRHArray`
ismWeakRef	Weak reference to the ISM containing this instance
coordToPixel	Converts coordinates (q,r) → pixel (dispatches hexa/square)
pixelToCoord	Converts pixel → coordinates (q,r) (dispatches hexa/square)

// Coordinate ↔ pixel conversion:
FVector2D pixel = FCHexaMakerTile::coordToPixel(q, r, tileSize, true);  // hexa
FVector2D pixel = FCHexaMakerTile::coordToPixel(q, r, tileSize, false); // square

FVector2D coord = FCHexaMakerTile::pixelToCoord(x, y, tileSize, true);  // hexa
FVector2D coord = FCHexaMakerTile::pixelToCoord(x, y, tileSize, false); // square