Summary

Tighten gameplay feel and make builds frictionless. This issue bundles small, safe improvements:

• Smooth, frame-rate-independent movement viadelta-time.
• No-stutter SFX withaudio clip pooling.
• Progressivedifficulty curve + spawn scheduler.
• Hitbox tuning + player i-frames after hit.
• Remove local JavaFX SDK path by usingjavafx-maven-plugin.
• AddCI (build + test) andpackaging (jpackage) for one-click runs.

Scope & Tasks

1) Frame-rate independence

• Replace fixed per-frame movement with delta time inAnimationTimer.
• Capdt (e.g., 0.033s) to avoid tunneling after GC pauses.

Sketch

newAnimationTimer() {privatelonglastNs =0L;@Overridepublicvoidhandle(longnow) {if (lastNs ==0L) {lastNs =now;return; }doubledt =Math.min((now -lastNs) /1_000_000_000.0,0.033);// ~30 ms caplastNs =now;player.update(dt);enemies.forEach(e ->e.update(dt));bullets.forEach(b ->b.update(dt));physics.update(dt);ui.render();    }}.start();

2) Audio stutter fix (pooling)

• PoolAudioClip/MediaPlayer for repeated SFX (shoot/hit/power-up).
• Volume & rate configurable via constants.

Sketch

classSfxPool {privatefinalList<AudioClip>shots;privateinti =0;SfxPool(URLwavUrl,intsize) {shots =IntStream.range(0,size)            .mapToObj(n ->newAudioClip(wavUrl.toString()))            .collect(Collectors.toList());    }voidplayShot() {AudioClipc =shots.get(i++ %shots.size());c.stop();c.play();    }}

3) Difficulty curve & spawns

• Spawn rate & enemy speed scale with score/time.
• Boss every N points with telegraphed warning.
• Power-up weighting increases when player is low on lives.

Sketch

doubledifficulty =1.0 + (score /250.0) +elapsedMinutes *0.25;spawner.setSpawnIntervalSeconds(Math.max(0.25,1.5 /difficulty));enemyBaseSpeed =120 *difficulty;

4) Hitboxes & i-frames

• Slightly shrink collision bounds (feel > math).
• Add 1.0s invulnerability after hit (blink sprite).

Sketch

booleancollides(Nodea,Nodeb) {BoundsA =a.getBoundsInParent();BoundsB =b.getBoundsInParent();doublepad =6;// shrink by 6pxreturnA.getMaxX()-pad >B.getMinX()+pad &&A.getMinX()+pad <B.getMaxX()-pad &&A.getMaxY()-pad >B.getMinY()+pad &&A.getMinY()+pad <B.getMaxY()-pad;}

5) Input polish

• Key repeat & “diagonal feels right”: normalize vector, clamp speed.
• AddPause (P) andMute (M).

6) Build: remove SDK path; add packaging

• Switch toorg.openjfx:javafx-maven-plugin so no local SDK path is needed.
• Addjpackage profile to produce platform installers.
• Embed assets insrc/main/resources and load viagetResource.

POM snippet

<plugin>  <groupId>org.openjfx</groupId>  <artifactId>javafx-maven-plugin</artifactId>  <version>0.0.8</version>  <configuration>    <mainClass>com.yourgame.SpaceShooter</mainClass>    <launcher>SpaceShooter</launcher>    <stripNativeCommands>true</stripNativeCommands>    <jlinkZip>true</jlinkZip>    <modules>      <module>javafx.controls</module>      <module>javafx.media</module>    </modules>  </configuration></plugin>

7) CI & Tests

• GitHub Actions:mvn -B -ntp -DskipTests=false verify.
• Headless smoke tests (logic only; no Stage) for spawn math & collisions.
• Optional: TestFX stage tests behind-Dtestfx.headless=true.

Acceptance Criteria

• ✅ Player speed & projectile speed are consistent at 60fps and 120fps (simulate by throttling) with <5% variance.
• ✅ No audible stutter on rapid fire (≥8 shots/sec).
• ✅ Spawn rate & enemy speed visibly scale with score/time; boss appears on schedule.
• ✅ Post-hit i-frames prevent immediate double damage; player sprite blinks.
• ✅mvn javafx:run workswithout editing a local JavaFX SDK path.
• ✅ CI workflow passes on Ubuntu runner; a packaged artifact is produced viamvn -Ppackage.

Nice-to-have (future)

• Quadtree for broad-phase collision when entities > 400.
• Screen-space shaders (flash on boss entry).
• Save best score (Preferences API) + simple settings modal.