FBrush

One brush application, in fixed point because strokes replicate as commands and must produce the same tiles on every machine.

Declaration

struct FBrush

Header: #include "Native/TerrainEdit.h"
Module: PublicDependencyModuleNames.Add("OrreryTerrainCore"); in your module’s Build.cs.
Stability: Stable: changes within a major version only add.

Description

The mask fields (record version 5) carry every dab's final mask, angle, aspect and flags, so a replay never derives them. With MaskHash 0 they stay at their defaults, and the brush applies exactly as before them.

Properties

Name	Type	Default	Meaning
`Kind`	`EBrushKind`	`EBrushKind::Raise`	—
`Falloff`	`EFalloff`	`EFalloff::Smooth`	—
`CentreX_mm`	`int64_t`	`0`	Relative to the terrain origin.
`CentreY_mm`	`int64_t`	`0`	—
`Radius_mm`	`uint32_t`	`10000`	The disc's radius; with a mask, half the mask's longer side. A Stamp's is bounded by `FSculptLimits::MaxStampRadius_mm`, any other brush's by MaxRadius_mm.
`Strength_mm`	`int32_t`	`100`	Height change at the centre per application (Raise, Lower, Smooth); Flatten's cap on every post's move per application; a Stamp's peak height over FlattenTo_mm (negative digs).
`FlattenTo_mm`	`FHeightMm`	`0`	Flatten's plane, mm; a Stamp's base height.
`Channel`	`FChannelId`	`0`	PaintChannel only.
`ChannelValue`	`uint8_t`	`0`	PaintChannel only.
`FalloffStart_q16`	`uint16_t`	`0`	The inner radius of full strength, in 1/65536 of the radius (kFalloffStartOne); 0 = the falloff starts at the centre.
`FlattenDirection`	`EFlattenDirection`	`EFlattenDirection::Both`	Flatten only.
`PaintLayer`	`uint8_t`	`0`	Paint only: the material layer id, 0..255.
`PaintOpacity`	`uint8_t`	`255`	Paint only: the weight the layer moves toward, 0..255 (255 = the layer alone).
`MaskHash`	`uint64_t`	`0`	The brush mask, by its content hash (64 bits over the mask's canonical bytes); 0 = no mask. A mask scales every kind's falloff weight per post; a Stamp's mask is its shape. Every machine samples the same bytes, and a hash the terrain does not hold is refused (`ESculptRefusal::UnknownMask`), never applied differently.
`MaskAngle`	`uint16_t`	`0`	The mask's rotation in 1/65536 of a turn (kBrushAngleTurn), counter-clockwise from +X seen from above; the mask's columns follow the rotated +X, its rows the rotated +Y. 0 without a mask.
`MaskFlags`	`uint8_t`	`0`	kBrushMaskMirror, kBrushMaskSquare and kBrushMaskBicubic; any other bit is refused. 0 without a mask.
`StampBlend`	`EStampBlend`	`EStampBlend::Add`	Stamp only: how its target meets the ground. Add on every other kind.
`MaskAspect_q8`	`uint16_t`	`kBrushAspectSquare`	The mask's width over its height (its local X side over its local Y side), in 1/256: kBrushAspectSquare is square, 512 twice as wide as tall, 128 twice as tall as wide; 0 is refused. The longer side spans 2 × Radius_mm and the shorter is scaled by the ratio, rounded up (BrushMaskHalfSides). kBrushAspectSquare without a mask.