Materials and Wall Paint — Wall Plugin

Materials and Wall Paint

The CodPassionWall plugin supports painting wall surfaces with solid colors or tiled textures. Painting works at runtime from Blueprint/C++ and from the editor panel’s Paint Wall mode.

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Required materials

Every AWallLineActor uses two materials:

Property	Purpose
WallMaterial	The base visual material for the wall mesh surface.
wall_painter_material	A special material that supports runtime painting via a render target. Required for painting to work.

Assign both in the Details panel under WallPlugin | Wall | Components, or pass them when spawning.

TODO verify

Confirm whether the shipped PlaceableWall_BP has these materials pre-assigned, or whether the user must assign them manually. Also confirm the technical requirements for wall_painter_material (e.g. whether it must reference a render target parameter).

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Painting from the editor panel

In the CodPassionWall editor panel, click Paint Wall to enter paint mode. See Build Mode – Paint Wall for the full workflow and all panel controls.

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Painting from Blueprint or C++

Wall actors implement IWallBpInterface. All paint functions are available through this interface.

Using the unified DrawToWall function

The recommended approach is to fill an FWallDrawParams struct and call Draw To Wall:

// Set up params
DrawParams.DrawMode = Color          ← or Texture
DrawParams.StartCenterWallPosition = (first hit result on wall)
DrawParams.EndCenterWallPosition   = (second hit result on wall)
DrawParams.bFill = false            ← true = fill entire wall
DrawParams.MergeDistance = 0.0

// Color mode
DrawParams.Color = FLinearColor(1, 0, 0, 1)

// OR Texture mode
DrawParams.Texture = (your Texture2D asset)
DrawParams.XScale = 1.0
DrawParams.YScale = 1.0
DrawParams.bNoYWrapping = false

// Execute
WallActor (via IWallBpInterface) -> Draw To Wall (DrawParams)
WallActor -> Commit Draw Call

Always call Commit Draw Call after Draw To Wall to finalize the operation. To cancel without applying, call Abbort Draw Call instead.

Caution

The function is named Abbort Draw Call (with a double-b). This is a typo in the source code. Use the exact node name as shown in the Blueprint editor.

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Convenience functions

For simpler cases, individual draw functions are also available:

Function	Description
Draw Color To Wall (color, startHit, endHit, fill)	Paints a region with a solid color.
Draw Color To Wall And Merge (color, startHit, endHit, fill, mergeDistance)	Same, with merge snapping.
Draw Texture To Wall (texture, startHit, endHit, xScale, yScale, fill, noYWrapping)	Tiles a texture across a region.
Draw Texture To Wall And Merge (...)	Same, with merge snapping.

All these functions still require a Commit Draw Call to take effect.

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FWallDrawParams struct fields

Field	Type	Default	Description
DrawMode	EWallDrawMode	Color	Color Draw or Texture Draw
StartCenterWallPosition	FHitResult	—	Start of the region to paint. Use Get Surface To Wall Center Position to convert a raw hit to the wall center.
EndCenterWallPosition	FHitResult	—	End of the region to paint.
bFill	bool	false	If true, fills the entire wall regardless of start/end.
MergeDistance	float	0.0	Tolerance in cm to snap region edges to wall endpoints or nodes.
Color	FLinearColor	White	Paint color. Used when DrawMode = Color.
Texture	UTexture2D	none	Texture to tile. Used when DrawMode = Texture.
XScale	float	1.0	Horizontal tiling scale. Used when DrawMode = Texture.
YScale	float	1.0	Vertical tiling scale. Used when DrawMode = Texture.
bNoYWrapping	bool	false	Prevents vertical tiling. Used when DrawMode = Texture.

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Getting the correct wall position from a hit result

When you hit a wall with a line trace, use these helpers to convert the raw surface hit into the correct wall-center position for painting:

Function	Description
Get Surface To Wall Center Position (hitResult) → FVector	Returns the center position on the wall surface from a hit. Use this to fill StartCenterWallPosition and EndCenterWallPosition.
Get Bottom Center Position From Vector (vec) → FVector	Returns the bottom-center equivalent of a world position relative to the wall.

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Saving and restoring paint data

Paint data (the render-target pixel data for each wall side) is stored in the SavedSurfaceData property on the wall actor. This data is:

• Saved automatically as part of UWallGameSubsystem::SaveWalls
• Restored via UWallGameSubsystem::LoadWalls (through RestoreSurfaceData)

You can also save and restore manually:

WallActor -> Save Surface Data    ← writes render target into SavedSurfaceData
WallActor -> Restore Surface Data ← re-applies SavedSurfaceData to the wall material

TODO verify

The CHANGELOG entry for v2.3.0 states “saving and loading from walls (without color)”. The code contains full save/load structures for paint data. Confirm whether paint data is fully saved and loaded in v2.3.0, or whether the CHANGELOG description is accurate and paint is not yet persisted.

Memory considerations

Paint data is stored as raw BGRA8 pixel data per wall side. For long or tall walls, this data can become substantial. Keep this in mind if you have many painted walls in a save slot.

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Related pages

• Build Mode – Paint settings
• Troubleshooting