Aseprite Normal Maps Extension

Normal Map converts a grayscale height image into a tangent-space normal map, previewed live on the Aseprite canvas. It is the companion to Delta Parsec's Bevel: run the bevel tool to produce a height layer, then run this to turn it into normals.

It reads the height as perceptual luminance, measures surface slope with a Sobel gradient, and writes the encoded normal as RGB. A flat-facing pixel comes out as the standard light blue-purple (128, 128, 255).

What you can do

One normal map from the whole sprite
The Source control defaults to "Visible (flattened)", which composites all visible layers before computing the normal. A beveled base plus detail layers produce one correct map from the merged height, not one broken map per layer.

Single-layer mode
Set Source to "Active layer" to generate a normal map from just the selected layer in isolation.

Strength
Controls how pronounced the slopes are. Low strength gives a subtle surface; high strength gives sharp angular normals.

Invert Y for OpenGL vs DirectX
Engines disagree on which way the green channel points. Leave it off for OpenGL (green up), turn it on for DirectX (green down).

Preserve alpha
Keep the source transparency on the normal map, or output a fully opaque layer.

Live canvas preview
The result previews directly on the sprite canvas as you drag the sliders, the same way Aseprite's built-in filters do. Cancel reverts with no trace. Apply commits one clean undo step.

The full texture pipeline

1. Run Delta Parsec's Bevel on your base and detail layers with "Also output height map" enabled.
2. Hide the shaded Bevel layers, show the Bevel Height layers.
3. Run Normal Map with Source set to Visible.

Result: one correct normal map where the base recedes and the details raise, one smooth slope per edge.

Controls

• Source — Visible (flattened composite of all visible layers) or Active layer
• Strength — Slope intensity
• Invert Y — Off for OpenGL, on for DirectX green channel
• Preserve alpha — Keep source transparency or output a fully opaque layer