Enforce fullscreen rule across all samples and fix sample 0713 scaling.

Locks fullscreen capability to sample 0713 only.
Adds requirement to fully fill screen while maintaining aspect ratio.

PR: LEVEL 23.8 FULLSCREEN REGRESSION LOCK + FIX

Author: DavidQ

docs/dev/codex_commands.md

@@ -0,0 +1,12 @@
+MODEL: GPT-5.3-codex
+REASONING: high
+
+COMMAND:
+- Scan all samples
+- Remove fullscreen usage except sample 0713
+- Fix sample 0713 fullscreen scaling:
+  - Must fill entire screen
+  - Must preserve aspect ratio
+  - No letterboxing or unused space
+- Do NOT modify engine core
+- Package results into repo structure

docs/dev/commit_comment.txt

@@ -0,0 +1,6 @@
+Enforce fullscreen rule across all samples and fix sample 0713 scaling.
+
+Locks fullscreen capability to sample 0713 only.
+Adds requirement to fully fill screen while maintaining aspect ratio.
+
+PR: LEVEL 23.8 FULLSCREEN REGRESSION LOCK + FIX

docs/dev/reports/fullscreen_audit_report.txt

@@ -0,0 +1,9 @@
+Fullscreen Audit Report
+
+- Sample 0713: VALID (allowed fullscreen) — FIX REQUIRED: does not fully fill screen while maintaining aspect ratio
+- All other samples: MUST NOT include fullscreen
+
+Violations:
+- Any sample using engine.fullscreen = TRUE must be removed
+
+Status: LOCK ENFORCED + FIX REQUIRED

docs/dev/reports/validation_checklist.txt

@@ -1,8 +1,8 @@
-- [ ] fullscreen usage audit completed across samples
-- [ ] unauthorized fullscreen removed from all non-0713 samples
-- [ ] sample 0713 fullscreen fills screen correctly
-- [ ] sample 0713 maintains aspect ratio
-- [ ] fullscreen enter/exit validated for 0713
-- [ ] no unauthorized fullscreen behavior remains
-- [ ] no start_of_day changes
-- [ ] unrelated working-tree changes preserved
+Validation Checklist
+
+[ ] Only sample 0713 has fullscreen
+[ ] No other sample contains fullscreen flags
+[ ] Sample 0713 fills screen fully (no unused space)
+[ ] Aspect ratio preserved correctly
+[ ] No engine-level fullscreen enforcement added
+[ ] Codex respects rule in future PRs

docs/pr/BUILD_PR_LEVEL_23_8_FULLSCREEN_REGRESSION_LOCK_AND_AUDIT.md

@@ -0,0 +1,21 @@
+# BUILD PR LEVEL 23.8
+## Fullscreen Regression Lock and Audit
+
+### Purpose
+Lock fullscreen behavior rules and prevent future regression outside sample 0713.
+
+### Scope
+- Enforce rule: fullscreen ONLY allowed in sample 0713
+- Audit all samples for violations
+- Prevent Codex from introducing fullscreen elsewhere
+- Fix sample 0713 to correctly fill screen while maintaining aspect ratio
+
+### Constraints
+- No engine changes
+- No rendering changes outside sample 0713 behavior fix
+- No gameplay impact
+
+### Acceptance
+- Only sample 0713 contains fullscreen logic
+- All other samples explicitly exclude fullscreen
+- Sample 0713 fills screen correctly while preserving aspect ratio (no letterboxing gaps)

samples/phase-07/0713/fullscreenViewportFit.js

@@ -4,7 +4,7 @@ David Quesenberry
 04/18/2026
 fullscreenViewportFit.js
 */
-export function computeContainSize({
+export function computeCoverSize({
   viewportWidth,
   viewportHeight,
   designWidth,
@@ -14,7 +14,7 @@ export function computeContainSize({
   const baseHeight = Number.isFinite(designHeight) && designHeight > 0 ? designHeight : 540;
   const width = Number.isFinite(viewportWidth) && viewportWidth > 0 ? viewportWidth : baseWidth;
   const height = Number.isFinite(viewportHeight) && viewportHeight > 0 ? viewportHeight : baseHeight;
-  const scale = Math.min(width / baseWidth, height / baseHeight);
+  const scale = Math.max(width / baseWidth, height / baseHeight);
   return {
     width: Math.max(1, Math.floor(baseWidth * scale)),
     height: Math.max(1, Math.floor(baseHeight * scale)),
@@ -47,24 +47,32 @@ export function attachFullscreenViewportFit({
     maxHeight: canvas.style.maxHeight,
     margin: canvas.style.margin,
     display: canvas.style.display,
+    position: canvas.style.position,
+    left: canvas.style.left,
+    top: canvas.style.top,
+    transform: canvas.style.transform,
   };
 
   function apply() {
     if (!readFullscreenState(documentRef)) {
       return;
     }
-    const containSize = computeContainSize({
+    const coverSize = computeCoverSize({
       viewportWidth: windowRef.innerWidth,
       viewportHeight: windowRef.innerHeight,
       designWidth,
       designHeight,
     });
-    canvas.style.width = `${containSize.width}px`;
-    canvas.style.height = `${containSize.height}px`;
+    canvas.style.width = `${coverSize.width}px`;
+    canvas.style.height = `${coverSize.height}px`;
     canvas.style.maxWidth = 'none';
     canvas.style.maxHeight = 'none';
-    canvas.style.margin = '0 auto';
+    canvas.style.margin = '0';
     canvas.style.display = 'block';
+    canvas.style.position = 'fixed';
+    canvas.style.left = '50%';
+    canvas.style.top = '50%';
+    canvas.style.transform = 'translate(-50%, -50%)';
   }
 
   function reset() {
@@ -74,6 +82,10 @@ export function attachFullscreenViewportFit({
     canvas.style.maxHeight = baselineStyles.maxHeight;
     canvas.style.margin = baselineStyles.margin;
     canvas.style.display = baselineStyles.display;
+    canvas.style.position = baselineStyles.position;
+    canvas.style.left = baselineStyles.left;
+    canvas.style.top = baselineStyles.top;
+    canvas.style.transform = baselineStyles.transform;
   }
 
   function syncWithFullscreenState() {

samples/phase-07/0713/main.js

@@ -19,6 +19,18 @@ const engine = new Engine({
   canvas,
   width: 960,
   height: 540,
+  // Sample 0713 owns fullscreen sizing behavior directly. Disable bezel-driven
+  // canvas relayout so cover-fit fullscreen can fill the viewport.
+  fullscreenBezelLayer: {
+    attach() {},
+    detach() {},
+    sync() {
+      return {
+        visible: false,
+        reason: 'sample-managed-fullscreen-layout',
+      };
+    },
+  },
 });
 
 const scene = new FullscreenAbilityScene();

tests/samples/FullscreenAbility0713ViewportFit.test.mjs

@@ -1,7 +1,7 @@
 import assert from "node:assert/strict";
 import {
   attachFullscreenViewportFit,
-  computeContainSize,
+  computeCoverSize,
 } from "../../samples/phase-07/0713/fullscreenViewportFit.js";
 import FullscreenAbilityScene from "../../samples/phase-07/0713/FullscreenAbilityScene.js";
 
@@ -22,21 +22,21 @@ function createEventTarget(initialState = {}) {
 }
 
 export function run() {
-  const exactFit = computeContainSize({
+  const exactFit = computeCoverSize({
     viewportWidth: 1920,
     viewportHeight: 1080,
     designWidth: 960,
     designHeight: 540,
   });
   assert.deepEqual(exactFit, { width: 1920, height: 1080 });
 
-  const letterboxed = computeContainSize({
+  const covered = computeCoverSize({
     viewportWidth: 1920,
     viewportHeight: 1200,
     designWidth: 960,
     designHeight: 540,
   });
-  assert.deepEqual(letterboxed, { width: 1920, height: 1080 });
+  assert.deepEqual(covered, { width: 2133, height: 1200 });
 
   const canvas = {
     style: {
@@ -46,6 +46,10 @@ export function run() {
       maxHeight: "",
       margin: "",
       display: "",
+      position: "",
+      left: "",
+      top: "",
+      transform: "",
     },
   };
   const documentRef = createEventTarget({ fullscreenElement: null });
@@ -60,21 +64,29 @@ export function run() {
 
   documentRef.fullscreenElement = canvas;
   fit.apply();
-  assert.equal(canvas.style.width, "1920px");
-  assert.equal(canvas.style.height, "1080px");
+  assert.equal(canvas.style.width, "2133px");
+  assert.equal(canvas.style.height, "1200px");
   assert.equal(canvas.style.maxWidth, "none");
+  assert.equal(canvas.style.position, "fixed");
+  assert.equal(canvas.style.left, "50%");
+  assert.equal(canvas.style.top, "50%");
+  assert.equal(canvas.style.transform, "translate(-50%, -50%)");
 
   windowRef.innerWidth = 1280;
   windowRef.innerHeight = 1024;
   windowRef.trigger("resize");
-  assert.equal(canvas.style.width, "1280px");
-  assert.equal(canvas.style.height, "720px");
+  assert.equal(canvas.style.width, "1820px");
+  assert.equal(canvas.style.height, "1024px");
 
   documentRef.fullscreenElement = null;
   documentRef.trigger("fullscreenchange");
   assert.equal(canvas.style.width, "");
   assert.equal(canvas.style.height, "");
   assert.equal(canvas.style.maxWidth, "960px");
+  assert.equal(canvas.style.position, "");
+  assert.equal(canvas.style.left, "");
+  assert.equal(canvas.style.top, "");
+  assert.equal(canvas.style.transform, "");
 
   const scene = new FullscreenAbilityScene();
   let requestCount = 0;