Contour Shaders — Outline Overhaul

Finally! got around to fixing and upgrading the entire outline system. took a while but its in a much better spot now.

Fixes

Hand Outline Disappearing Behind Mobs
This one was most annoying bug for a while. The problem was that entities and the hand were both writing into the same single channel on colortex9, so when the hand was sitting behind a mob the depth check just killed it with no way to tell the two apart. Split them into separate channels (RG8 now instead of R8), hand gets green, entities get red, and composite2 just skips the depth check entirely when it sees a hand fragment. Completely gone now!!

Changes

Kernel now uses gaussian weights
Switched from the flat equal-weight sample loop to a gaussian falloff. Closer pixels to the edge boundary contribute more, further ones fade out. Outlines look way cleaner before TAA even runs, no more stairstepping.

Depth bias is no longer hardcoded
The old 0.005 flat bias was always a hack. Replaced it with something derived from the projection matrix so it represents an actual 5cm world-space gap at whatever depth youre at. Fixes the flickering on terrain and the weird culling when mobs stand right on the ground.

Entity separation threshold scales with FOV
The 0.4 threshold that separates overlapping entities was completely hardcoded. Zoom in with a spyglass and it falls apart. Tied it to gbufferProjection[1][1] now so it adjusts based on your actual focal length. works properly from 30 degrees.

Outline thickness is now FOV-accurate
Same problem as above. the old thickness formula would bloat at wide FOV and shrink at narrow FOV. Corrected it against a 70 degree reference focal length so what you set is what you actually see on screen regardless of your FOV.

Mask now stores alpha instead of hard 1.0
Entities and hand were just slamming a flat 1.0 into the mask no matter what. Changed both passes to write color.a instead. Slimes, Spectral arrows, anything translucent now gets a proportionally soft outline instead of a fully opaque border around a see-through mob.

Changelog

Added

• Rainbow Outline Mode (OUTLINE_RAINBOW) — optional extra color mode that makes the outline cycle through rainbow colors
• OUTLINE_RAINBOW_CYCLE — toggle animated vs fixed rainbow color
• OUTLINE_RAINBOW_HUE — fixed hue used when animation is off (0.00 Red → 0.17 Yellow → 0.33 Green → 0.50 Cyan → 0.67 Blue → 0.83 Magenta)
• OUTLINE_RAINBOW_SPEED — animation cycle speed when OUTLINE_RAINBOW_CYCLE is on
• en_US.lang entries for all new Contour Outline options and screen

Fixed

• Fixed 2-column UI layout gap in CONTOUR_OUTLINE_SETTINGS screen — OUTLINE_DARKNESS and OUTLINE_RAINBOW now share a row correctly instead of OUTLINE_RAINBOW being orphaned to its own row due to a double <empty> token pair between them

Contour Shaders v1.0.1

A bug-fix release on top of v1.0.

What's fixed

Outlines on overlapping entities now render correctly. Previously, when two mobs overlapped on screen — or when your hand overlapped a mob — the outline would disappear at the intersection. This happened because the edge-detection pass skipped any pixel that belonged to an entity, so mob-on-mob overlap zones were silently ignored.

The outline pass now runs on every pixel. Background pixels use a lenient depth threshold to handle coplanar surfaces like feet on the ground. Entity pixels use a view-space depth comparison converted to real in-game metres, requiring a neighbour to be at least 0.4 blocks closer before drawing — this distinguishes a separate mob in front from natural surface curvature on the same mob, preventing interior self-outlining while keeping all overlap cases correct.

Known issue (carried forward, not introduced in this release)

Outlines may disappear when you are very close to a mob. This is a remaining depth precision limitation and will be addressed in a future update!

Compatibility: Iris 1.7+ · Minecraft 1.21+