visual.yml

name: Visual

# Draws the scenes in VisualProbe and checks they still look the way they were
# recorded. Kept apart from the unit tests because it needs a screen, takes
# longer, and can fail for a reason the tests never can: a different machine
# drawing the same thing slightly differently.
#
# The recorded frames in src/test/resources/parity/frames are pixel-for-pixel.
# Two runs on one machine are bit-identical, but two different machines are only
# identical if they rasterise the same way, and the runner is not the machine the
# frames were recorded on. If this job fails on something nobody changed, take
# the drawn-frames artifact below, put it in src/test/resources/parity/frames,
# and commit that: the runner then becomes what the frames are recorded against.

on:
  pull_request:
    branches:
      - main
  push:
    branches:
      - main

jobs:
  visual:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v7

      - name: Set up Java
        uses: actions/setup-java@v5
        with:
          distribution: temurin
          java-version: 17
          cache: maven

      # A costume cannot be loaded without a window, so there has to be a screen
      # even though nobody is going to look at it.
      - name: Install Xvfb
        run: sudo apt-get update && sudo apt-get install -y xvfb

      - name: Check the scenes still look the same
        run: ./scripts/visual-parity.sh

      # Both halves of the story: each scene that differs, boxed where it moved,
      # and under as-drawn/ the same scenes as this machine drew them.
      - name: Upload what differed
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: visual-parity
          path: target/visual-parity/
          if-no-files-found: ignore