[Paper2D] [Lighting] Tilemaps with masked sprites respond to all lighting at incorrect directions.

Description

It appears that tilemaps using lit methods of rendering are now subject to a lighting bug. If the material for the tilemap is using a ‘masked’ method of rendering (as is the standard for all Paper2D materials) all lighting will appear at incorrect angles.

  • Point, box, and spot lights projected directly downwards onto a flat plane will only have roughly 50% of their light projected upon them, spread out over a cone.
  • Rotating the plane will change the direction of the light’s cone.
  • Directional lights will always be angled incorrectly against the tilemap plane. Pointing a directional light at flat tilemap plane will result in no light. If the plane is rotated upwards, all light will appear against the tilemap, despite the light and the plane now pointing in perpendicular directions.
  • If a tilemap’s material uses ‘translucent’ instead of ‘masked’, the lighting will appear logically against it, with no inconsistencies between rotation or lighting rendering.

This result seemingly differs from how tilemaps were lit circa Unreal 4.17.

Reproduction Steps

  1. Delete all content in scene.
  2. Import a texture for a tilemap.
  3. Apply paper 2 settings.
  4. Create tileset.
  5. Create tilemap.
  6. Place tilemap in scene, flat (x as -90).
  7. Duplicate default paper 2D material with one that is lit. Make sure that the tileset is using a “masked” blend mode. Apply to the tilemap.
  8. Place a bright point-light above the tilemap, observe results. Bug: light’s radius is not fully visible against the tilemap.
  9. Rotate the tilemap along Z, observe results. Bug: light’s radius will rotate.
  10. Place a directional light in scene. Set the directional light to be pointed directly downwards, towards the tilemap. Bug: tilemap will no be affected by the directional light.
  11. Rotate the tilemap so that it’s x value is no longer -90, but 0, observe results. Bug: tilemap is now lit by the directional light even though they are directed perpendicularly to one another.
  12. Rotate the tilemap back to -90 along X.
  13. Open the material applied to the tilemap.
  14. Set the blend mode to “Translucent”. Observe results. Tilemap will appear to be properly lit.

.

Expected Result

Tile maps are lit in logical ways regardless of their blend modes.

Addendum

A sample project of this bug can be found at: Dropbox - TilemapLights.rar - Simplify your life
This bug has also been logged via: Unreal Engine Community

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Thanks

Hello, any news about this bug? we need this solved to progress with our project. Thanks