Harden the tooling paths and atlas paging, and fix the trim pipeline for 26.x

.github/workflows/generate-spritesheet.yml

@@ -1,5 +1,7 @@
 name: Generate Spritesheet
 
+# Dispatch this on any branch. The regenerated assets are committed back to the branch it ran on,
+# or a pull request is opened against that branch, so it works inside an open PR as well as on master.
 on:
   workflow_dispatch:
     inputs:
@@ -42,25 +44,23 @@ jobs:
   generate:
     runs-on: ubuntu-latest
 
+    env:
+      # The render step draws every block and item in the Maven JVM, so give it room for the renderer's context.
+      MAVEN_OPTS: -Xmx4g
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v7
         with:
           fetch-depth: 0
 
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v6.0.1
         with:
           java-version: '25'
           distribution: 'temurin'
           cache: maven
 
-      - name: Set up .NET SDK
-        if: inputs.pipeline == 'full' || inputs.pipeline == 'render-only'
-        uses: actions/setup-dotnet@v6
-        with:
-          dotnet-version: '10.0.x'
-
       - name: Build Tooling Module
         run: mvn -pl tooling -am compile -DskipTests -q
 
@@ -187,7 +187,7 @@ jobs:
           ## Asset Changes
 
           $DIFF_TABLE" \
-            --base master || echo "PR already exists"
+            --base "${{ github.ref_name }}" || echo "PR already exists"
 
       - name: Commit Directly
         if: steps.changes.outputs.has_changes == 'true' && inputs.create_pr == false
@@ -196,7 +196,7 @@ jobs:
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git add generator/src/main/resources/minecraft/assets/
           git commit -m "Update spritesheet assets"
-          git push origin master
+          git push origin HEAD:"${{ github.ref_name }}"
 
       - name: Upload Artifacts
         if: steps.changes.outputs.has_changes == 'true'

README.md

@@ -664,31 +664,47 @@ MinecraftImageGenerator/
 The project includes a GitHub Actions workflow for generating and updating Minecraft item spritesheets and overlays. This is triggered manually via `workflow_dispatch` and supports:
 
 - Downloading Minecraft assets for any version
-- Rendering items at configurable sizes (requires .NET 10)
+- Rendering every block and item icon at a configurable size
 - Generating sprite atlases with coordinate metadata
 - Generating item overlays for colored variants (armor, potions, etc.)
 
-### Configurable tooling outputs and atlas pages
+The render step draws the icons in-process with
+[asset-renderer](https://github.com/minecraft-library/asset-renderer), an Apache-2.0 Java library that reads
+the client JAR the download step cached. It needs nothing beyond the JDK, and the tooling pins it to a commit
+in `tooling/pom.xml` because the library has no tagged releases.
 
-`MinecraftAssetTool` accepts `--work-dir=<path>`, `--output-dir=<path>` and
-`--renderer-dir=<path>`. Set these separately for each Minecraft version when
-calling the tooling from another build system. The same paths can be set with
-`generator.tooling.workDir`, `generator.tooling.outputDir` and
-`generator.tooling.rendererDir` JVM system properties. Existing default paths remain unchanged.
+### Configurable tooling outputs and atlas pages
 
-`--size` controls the rendered image size and the default item-atlas tile size.
-`--tile-size` overrides just the tile size. `--atlas-width`, `--atlas-height`
-and `--padding` control page bounds and transparent gutters. Standalone
-`SpritesheetGenerator` supports these atlas options and `--input`.
+By default the tooling keeps its scratch files under `tooling/build` and writes
+spritesheets and JSON into `generator/src/main/resources/minecraft/assets`.
+`MinecraftAssetTool`, `SpritesheetGenerator` and `OverlayGenerator` all accept
+`--work-dir=<path>` and `--output-dir=<path>` to move those, which is handy when
+another build drives the tooling once per Minecraft version. The same two
+settings can be given as the JVM system properties `generator.tooling.workDir`
+and `generator.tooling.outputDir`, which is the way to pass them through the
+Maven profiles. A flag wins over a property.
+
+`--size` sets the render size only. Atlas tiles stay at 256px unless you pass
+`--tile-size`. `--atlas-width`, `--atlas-height` and `--padding` bound each page
+and add a transparent gutter around every tile. All of these are checked before
+any download or render starts, so a bad value fails immediately. The overlay
+generator reads its definitions from a file bundled with the tooling; pass
+`--overlay-definitions=<file>` to use your own instead.
 
 ```text
-MinecraftAssetTool --download --render --spritesheet --no-clean --version=26.3
+MinecraftAssetTool --download --render --spritesheet --version=26.3
   --work-dir=build/26.3/work --output-dir=build/26.3/generated
-  --size=64 --atlas-width=2048 --atlas-height=2048 --padding=1
+  --tile-size=64 --atlas-width=2048 --atlas-height=2048 --padding=1
 ```
 
-The first page keeps its original PNG filename; additional pages use `-1`,
-`-2`, etc. Coordinate JSON remains an array with `name`, `x`, `y`, and `size`,
-plus `page`, `atlas` (PNG filename), `atlasWidth`, and `atlasHeight` for each entry.
-Paging and padding are opt-in. The generator library's bundled single-page
-resources retain their existing default layout.
+When the tiles do not fit on one page, the first page keeps its file name and
+later pages get `-1`, `-2` and so on before the extension. Every coordinates
+entry carries `page` and `atlas` (the PNG file name) alongside `name`, `x`, `y`
+and `size`. Numbered pages left behind by an earlier, larger run are deleted.
+The generator library reads the `atlas` field, so a paged atlas placed in its
+resources loads without any other change.
+
+The tool deletes `tooling/build` at the end of a run, as it always has. A work
+directory you chose yourself is kept unless you pass `--clean`, and `--no-clean`
+keeps the default one too. Cleanup refuses to run when the work directory
+contains the current directory or the output directory.

generator/pom.xml

@@ -171,6 +171,14 @@
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <!-- Mockito's inline mock maker must be attached as an agent on modern JDKs. Only this module mocks. -->
+                    <argLine>-javaagent:${settings.localRepository}/org/mockito/mockito-core/${mockito.version}/mockito-core-${mockito.version}.jar</argLine>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>io.github.git-commit-id</groupId>
                 <artifactId>git-commit-id-maven-plugin</artifactId>