fix(babylon_setup.js): fix exit not generating properly

Co-authored-by: Copilot <copilot@github.com>

src/babylon_setup.js

@@ -126,6 +126,7 @@ let chestMap = new Map(); // key: "x,y" -> {mesh, opened}
 let keyChestKey = null;
 let exitBox = null;
 let exitGridPos = null; // track exit grid position for collision checking
+let spawnGridPos = null; // track spawn grid position for validation
 let spawnMarker = null;
 const cellSize = 2;
 
@@ -139,6 +140,7 @@ function clearLevelMeshes() {
     if (exitBox) { try { exitBox.dispose(); } catch(e){}; exitBox = null; }
     if (spawnMarker) { try { spawnMarker.dispose(); } catch(e){}; spawnMarker = null; }
     exitGridPos = null;
+    spawnGridPos = null;
 }
 
 // Simple seeded RNG
@@ -209,6 +211,26 @@ function findDeadEnds(grid) {
     return dead;
 }
 
+function gridCellToWorld(grid, x, y) {
+    const halfW = (grid[0].length * cellSize) / 2;
+    const halfH = (grid.length * cellSize) / 2;
+    return new BABYLON.Vector3(
+        x * cellSize - halfW + cellSize / 2,
+        0,
+        y * cellSize - halfH + cellSize / 2,
+    );
+}
+
+function isWalkableCell(grid, x, y) {
+    return y >= 0 && y < grid.length && x >= 0 && x < grid[0].length && grid[y][x] === 0;
+}
+
+function isReservedCell(x, y) {
+    if (chestMap.has(`${x},${y}`)) return true;
+    if (exitGridPos && exitGridPos.x === x && exitGridPos.y === y) return true;
+    return false;
+}
+
 function buildLevelFromGrid(grid) {
     clearLevelMeshes();
     const h = grid.length;
@@ -295,48 +317,78 @@ function placeExit(grid, seed) {
         exitGridPos = { x, y };
     }
     
-    const [x,y] = exitGridPos;
+    const [x,y] = [exitGridPos.x, exitGridPos.y];
-    const halfW = (grid[0].length * cellSize) / 2;
+    if (!isWalkableCell(grid, x, y)) {
-    const halfH = (grid.length * cellSize) / 2;
+        console.warn("Exit selected on non-walkable cell", { x, y });
-    const ex = x*cellSize - halfW + cellSize/2;
+        return;
-    const ez = y*cellSize - halfH + cellSize/2;
+    }
+    const exitWorld = gridCellToWorld(grid, x, y);
+    const ex = exitWorld.x;
+    const ez = exitWorld.z;
+    const worldSpan = Math.max(grid[0].length, grid.length) * cellSize;
     
-    // Ground plane indicator
+    // Ground plane indicator (larger + slightly raised to avoid z-fighting)
-    const plane = BABYLON.MeshBuilder.CreateGround('exitZone', { width: cellSize*0.9, height: cellSize*0.9 }, scene);
+    const plane = BABYLON.MeshBuilder.CreateGround('exitZone', { width: cellSize*1.4, height: cellSize*1.4 }, scene);
-    plane.material = new BABYLON.StandardMaterial('exitMat', scene);
+    const exitMat = new BABYLON.StandardMaterial('exitMat', scene);
-    plane.material.emissiveColor = new BABYLON.Color3(0.9, 0.8, 0.2);
+    exitMat.diffuseColor = new BABYLON.Color3(0.25, 0.2, 0.03);
-    plane.position = new BABYLON.Vector3(ex, 0.01, ez);
+    exitMat.emissiveColor = new BABYLON.Color3(1.0, 0.85, 0.15);
+    exitMat.disableLighting = true;
+    plane.material = exitMat;
+    plane.position = new BABYLON.Vector3(ex, 0.08, ez);
     exitBox = plane;
     levelMeshes.push(plane);
     
-    // Tall pillar for visibility
+    // Very tall beacon for visibility over maze walls
-    const pillar = BABYLON.MeshBuilder.CreateCylinder('exitPillar', { diameter: cellSize*0.3, height: cellSize*3.0 }, scene);
+    const beaconHeight = Math.max(18, worldSpan * 0.8);
+    const pillar = BABYLON.MeshBuilder.CreateCylinder('exitPillar', { diameter: cellSize*0.55, height: beaconHeight }, scene);
     const pillarMat = new BABYLON.StandardMaterial('exitPillarMat', scene);
     pillarMat.diffuseColor = new BABYLON.Color3(0.95, 0.8, 0.1);
-    pillarMat.emissiveColor = new BABYLON.Color3(0.3, 0.25, 0.05);
+    pillarMat.emissiveColor = new BABYLON.Color3(1.0, 0.7, 0.1);
+    pillarMat.disableLighting = true;
     pillar.material = pillarMat;
-    pillar.position = new BABYLON.Vector3(ex, cellSize*0.75, ez);
+    pillar.position = new BABYLON.Vector3(ex, beaconHeight * 0.5, ez);
     levelMeshes.push(pillar);
+
+    // Bright orb at the top of beacon
+    const orb = BABYLON.MeshBuilder.CreateSphere('exitOrb', { diameter: cellSize * 1.0 }, scene);
+    const orbMat = new BABYLON.StandardMaterial('exitOrbMat', scene);
+    orbMat.diffuseColor = new BABYLON.Color3(1.0, 0.9, 0.3);
+    orbMat.emissiveColor = new BABYLON.Color3(1.0, 0.9, 0.35);
+    orbMat.disableLighting = true;
+    orb.material = orbMat;
+    orb.position = new BABYLON.Vector3(ex, beaconHeight + cellSize * 0.7, ez);
+    levelMeshes.push(orb);
 }
 
 function spawnCameraAt(grid) {
-    const h = grid.length, w = grid[0].length;
+    const h = grid.length;
+    const w = grid[0].length;
+    let bestCell = null;
+    let bestDist = -1;
+
+    // Choose a valid spawn that is far from exit when possible.
     for (let y = 1; y < h - 1; y++) {
         for (let x = 1; x < w - 1; x++) {
-            // Skip walls
+            if (!isWalkableCell(grid, x, y)) continue;
-            if (grid[y][x] !== 0) continue;
+            if (isReservedCell(x, y)) continue;
 
-            // Skip chests
+            const d = exitGridPos ? Math.hypot(x - exitGridPos.x, y - exitGridPos.y) : 0;
-            if (chestMap.has(`${x},${y}`)) continue;
+            if (d > bestDist) {
+                bestDist = d;
+                bestCell = { x, y };
+            }
+        }
+    }
 
-            // Skip exit
+    if (!bestCell) {
-            if (exitGridPos && exitGridPos.x === x && exitGridPos.y === y) continue;
+        console.warn("No valid spawn cell found.");
+        return;
+    }
 
-            // Found valid spawn point
+    spawnGridPos = bestCell;
-            const halfW = (w * cellSize) / 2;
+    const spawnWorld = gridCellToWorld(grid, bestCell.x, bestCell.y);
-            const halfH = (h * cellSize) / 2;
+    const px = spawnWorld.x;
-            const px = x*cellSize - halfW + cellSize/2;
+    const pz = spawnWorld.z;
-            const pz = y*cellSize - halfH + cellSize/2;
 
     try {
         if (camera && camera.position) {
@@ -344,7 +396,6 @@ function spawnCameraAt(grid) {
         }
     } catch (e) {}
 
-            // Add spawn marker sphere
     if (spawnMarker) {
         try { spawnMarker.dispose(); } catch(e) {}
     }
@@ -356,10 +407,6 @@ function spawnCameraAt(grid) {
     marker.position = new BABYLON.Vector3(px, cellSize*0.2, pz);
     spawnMarker = marker;
     levelMeshes.push(marker);
-            
-            return;
-        }
-    }
 }
 
 function generateLevel() {
@@ -374,7 +421,20 @@ function generateLevel() {
     placeChestsOnDeadEnds(grid, dead, cfg.minChestDeadEnds, seed + cfg.level);
     placeExit(grid, seed + cfg.level);
     spawnCameraAt(grid);
-    sharedState.runtime.message = `Level ${cfg.level} generated.`;
+
+    const placementValid =
+        !!exitGridPos &&
+        !!spawnGridPos &&
+        isWalkableCell(grid, exitGridPos.x, exitGridPos.y) &&
+        isWalkableCell(grid, spawnGridPos.x, spawnGridPos.y) &&
+        !(exitGridPos.x === spawnGridPos.x && exitGridPos.y === spawnGridPos.y);
+
+    if (!placementValid) {
+        sharedState.runtime.message = `Placement warning: spawn/exit invalid on level ${cfg.level}.`;
+        console.warn("Invalid spawn/exit placement", { exitGridPos, spawnGridPos });
+    } else {
+        sharedState.runtime.message = `Level ${cfg.level} generated (spawn ${spawnGridPos.x},${spawnGridPos.y} / exit ${exitGridPos.x},${exitGridPos.y}).`;
+    }
     window.requestAnimationFrame(()=>{ /* let scene update */ });
 }