Glow

Overview

Adds a glow around a sprite, or along its inside edge. It is the luminous counterpart to Drop Shadow. Because it uses a distance transform rather than a blur, it can create pixel-art-friendly stepped glow controlled by steps. It is a common game-asset effect for magic, neon, and blinking collectible items.

Usage tips

• For pixel art, steps of 1–3 is the go-to range. 0 (smooth) creates many intermediate colors, so use stepped glow for palette-managed assets.
• radius=1 lights the first pixel next to the boundary. Radius is an inclusive reach measured from the boundary.
• Reserve at least radius pixels of padding with canvas_resize first so the glow is not clipped.
• For a pulsing animation, drive intensity with motion (Wobble), moving between about 0.5 and 1.5.
• Inside creates rim light along an inner edge. It works well for characters in night scenes or highlighted objects.

Common pitfalls

• The glow is clipped into a rectangle at the canvas edge: there is not enough padding. Expand the canvas by radius with canvas_resize.
• The glow mixes with the background and looks muddy: this node composites within the image. To additively composite against a background, create only the glow on black and place it over the background with blend(Add).
• The color count increased: the gradient from steps=0 is responsible. Set steps, or place palette_quantize downstream.

Technical details

• Falloff is calculated from the chamfer distance to the silhouette (alpha ≥ 0.5).
• An empty silhouette returns the source unchanged regardless of radius.
• Outside: treats pixels below alpha 0.5 as outside and places glow color there. Consequently, semi-transparent antialiasing pixels can change color or alpha.
• Inside: overlays the glow color on the inner edge. Alpha is unchanged.
• steps quantizes falloff, keeping the color count low without Palette Quantize.

Examples

1. Magic projectile: projectile sprite → Glow(Outside, steps: 2) for a two-step glow ring
2. Rim light: character → Glow(Inside, radius: 2) for a backlit edge
3. Neon sign: text → Glow(Outside, intensity: 1.5) → Blend(Add) over the background

Related nodes

• drop_shadow — the shadow counterpart, built by offsetting and expanding a silhouette
• outline — when you want a crisp outline rather than light
• gaussian_blur + blend(Add) — the classic manual glow setup
• motion — drives a pulsing animation