---
title: "Sprint 22 — Visual Briefing"
description: "Fog shader alpha tuning for semi-transparent layers per D-059"
type: sprint
status: archived
sprint: 22
team: "visual"
---

# Sprint 22: Wire — Visual Tasks

**Goal:** Fix the fog regression, wire the authored Sova content into a production population and triangle set, and activate the contamination pacing layer that gives the vertical slice its 30-minute shape.

**Branch:** `visual`
**Agents:** Araminta (art direction)

## New Tickets

| # | Title | Blocked by |
|---|-------|------------|
| #563 | Fog shader too opaque — tune alpha for semi-transparent layers per D-059 | #569 (client) |

Use `tooling/db/ticket show <id>` for full details.

## Key Decisions

- `decisions/perception.md` — D-059 (fog shader spec: light fog = desaturated 40-50%, brightness -30%; deep fog = near-monochrome with ~10% zone temperature tint; fog breathes with Perlin noise), D-011 (fog of perception is non-negotiable — world must be visible through fog, not hidden behind it), D-033 (entity color = relationship to player, must remain visible through fog overlay)
- `decisions/architecture.md` — D-066 (dual-scale grid, sim tiles vs visual tiles — fog gradient tuning is in visual-tile terms)
- `decisions/perception.md` — D-046 (three-reference lighting: warm amber = social/inhabited, cool white = institutional, mixed = transitional — zone temperature tint maps to this)

## Open Questions to Resolve Early

None blocking #563. But coordinate with Stig (client team) — **do not start #563 until #569 (fog architecture fix) is in client review.** The shader file is the same artifact. Starting early will cause a merge conflict.

## Notes

**#563 — Fog shader too opaque — tune alpha for semi-transparent layers per D-059**
- **Sequencing:** This ticket is intentionally blocked by client #569. Stig fixes the broken gradient and explored-tile architecture. Once #569 is in review and the shader is structurally correct, Araminta takes the final tuning pass.
- **The problem (from ticket):** Current alphas are too high — light fog (layer 2) at 0.25-0.55 and deep fog (layer 3) at 0.78-0.90. These values make fog feel like a wall, not a perceptual filter. D-059 specifies the world should be visible through the fog — desaturated and dimmed, not hidden.
- **Target behavior per D-059:**
  - **Clear (forward cone):** Nearly transparent. Fog alpha ≈ 0.0 in the cone center. Soft gradient at the edge.
  - **Explored (light fog):** World content fully visible through desaturation and dimming. Fog alpha in the range 0.25-0.35 — enough to signal "not current attention" without obscuring art. The 8-10s Perlin noise breathe animates within this range (±0.04). Entity D-033 colors visible but slightly muted.
  - **Previously explored (deep fog):** World visible but near-monochrome. Fog alpha 0.55-0.70. Zone temperature tint applied as a color shift, NOT an additional opaque overlay. Bar zone: warm dark tint. Hub zone: cool dark tint. Corridor: neutral dark. The 15-20s Perlin breathe cycle is more pronounced here.
  - **Unexplored:** Solid `#12141a`. Alpha 1.0. Correct as-is.
- **Files:**
  - `client/shaders/fog.gdshader` — primary. Tune the `fog_alpha` constant and the `DARK_OVERLAY` color. The zone temperature tint is currently not implemented — add it as a sampled `zone_tint_tex` lookup (the uniform already exists in the shader; wire the zone palette into it from `fog_state.gd`).
  - `client/scripts/autoloads/fog_state.gd` — may need zone tint texture population if the uniform is not yet wired.
  - `docs/architecture/fog-shader-spec.md` — update if the approach changes from the current spec.
- **Zone temperature palette (D-059 + D-046):**
  - Terminal/hub: `#1a1f2e` (cool blue-dark)
  - Last Shift/bar: `#2a1f15` (warm amber-dark)
  - Maintenance corridors: `#1a1a1a` (neutral dark)
- **Artistic test — the "Hopper test" (D-046):** After walking out of The Last Shift, the bar should still appear warm and inviting in deep fog — "the warm light is indifferent, not ironic." If the deep fog makes the bar's zone temperature tint readable as warm-dark against the surrounding cool-dark corridors, the tint is working. If everything looks the same dark, the tint needs more saturation.
- **Do not:** Apply D-033 relationship color tinting to the fog itself. Fog is a perceptual layer, not a relationship layer. Entity colors are unaffected by the fog shader — they render through it.
- **Acceptance:**
  - Light fog (explored): underlying art, sprites, furniture clearly visible at approximately 25-35% fog overlay.
  - Deep fog (previously explored): world visible but near-monochrome, zone temperature tint distinguishable between bar/hub/corridor.
  - Unexplored: solid near-black, unchanged.
  - Fog "breathes" — animated Perlin noise visible at both explored and previously-explored states.
  - No hard edges between fog states — all transitions are smooth.
  - Sign off from Stig (client team, who owns the underlying architecture) before merging.

## Dependency Chain

```
#569 (client fog architecture fix) → #563 (visual fog alpha tuning)
```

Araminta should not begin shader work until Stig's #569 is in review on the client branch.

## PR Workflow

When ready to submit, create a PR with `tea` CLI:

```bash
tea pr create --repo jpmschweitzer/settled-reach --login schweitz --title "fix(assets): Sprint 22 — fog shader alpha and zone temperature tint" --description "body" --base main --head visual
```