Fix mushroom cloud being clipped by simulation grid

src/ExplosionSim.js

@@ -60,8 +60,8 @@ export class ExplosionSim {
           // 3-step cel-shading quantization
           float stepped = floor(NdotL * 3.0 + 0.5) / 3.0;
 
-          // Height-based + global temperature color ramp
-          float h = clamp(vWorldPos.y / 12.0, 0.0, 1.0);
+          // Height-based + global temperature color ramp (world Y 0..40)
+          float h = clamp(vWorldPos.y / 38.0, 0.0, 1.0);
           float t = clamp(uGlobalTemp * (0.5 + 0.5 * h), 0.0, 1.0);
 
           // Smooth color transitions
@@ -96,9 +96,10 @@ export class ExplosionSim {
     });
 
     this.mc = new MarchingCubes(this.N, this.celMat, false, false, 200000);
-    this.mc.isolation = 0.12;
-    this.mc.scale.set(12, 12, 12);
-    this.mc.position.set(0, 0, 0);
+    this.mc.isolation = 0.14;
+    // Non-square: 16 wide × 40 tall — world Y goes 0 → 40 (grid bottom = ground)
+    this.mc.scale.set(8, 20, 8);
+    this.mc.position.set(0, 20, 0);
     this.scene.add(this.mc);
   }
 
@@ -165,16 +166,16 @@ export class ExplosionSim {
   _updateTimeline(t) {
     const s = this.solver, N = this.N;
 
-    // Detonation — inject massive initial energy
+    // Detonation — narrow initial fireball near ground
     if (!this.detonated && t > 0.05) {
       this.detonated = true;
-      s.injectSphere(N / 2, N * 0.12, N / 2, N * 0.15, 80, 50);
+      s.injectSphere(N / 2, N * 0.08, N / 2, N * 0.09, 80, 40);
     }
 
-    // Sustained fireball energy
-    if (t > 0.1 && t < 3.0) {
-      const strength = (1 - remap(t, 0.1, 3.0)) * 20;
-      s.injectSphere(N / 2, N * 0.12, N / 2, N * 0.08, strength, strength * 0.5);
+    // Sustained narrow stem injection at base
+    if (t > 0.1 && t < 4.5) {
+      const strength = (1 - remap(t, 0.1, 4.5)) * 22;
+      s.injectSphere(N / 2, N * 0.07, N / 2, N * 0.05, strength, strength * 0.4);
     }
 
     // Nachlauf-Stem (Mushroom stem injection)
@@ -190,11 +191,14 @@ export class ExplosionSim {
     s.vortexStrength = easeOutCubic(vp) * 8.0;
     s.vortexRadius = N * (0.1 + easeOutCubic(vp) * 0.15);
 
-    s.turbulenceStrength = 1.0 + 2.0 * clamp01(remap(t, 0.5, 3.0));
+    // Entrainment: inward pull creates narrow stem below the cap
+    s.entrainStrength = t > 1.0 ? Math.min(3.0, (t - 1.0) * 1.2) : 0;
+
+    s.turbulenceStrength = 0.8 + 1.5 * clamp01(remap(t, 0.5, 3.0));
     s.cooling = 0.998 - remap(t, 5, 20) * 0.008;
 
     // Global temperature for coloring
-    this.globalTemp = 1.0 - remap(t, 1.0, 12.0) * 0.85;
+    this.globalTemp = 1.0 - remap(t, 1.0, 14.0) * 0.86;
     this.celMat.uniforms.uGlobalTemp.value = this.globalTemp;
   }
 

src/FluidSolver.js

@@ -99,6 +99,7 @@ export class FluidSolver {
     this.turbulenceTime = 0;
     this.jacobiIters = 15;
     this.cooling = 0.995;        // temperature decay per step
+    this.entrainStrength = 0;    // inward pull to form narrow stem
   }
 
   step() {
@@ -148,7 +149,13 @@ export class FluidSolver {
     // 5. Cool temperature
     for (let i = 0; i < N*N*N; i++) {
       g.temp[i] *= this.cooling;
-      // No density dissipation — let advection+boundaries handle mass loss naturally
+    }
+
+    // 6. Open top: let gas flow out instead of being killed at the ceiling
+    for (let k = 0; k < N; k++)
+    for (let i = 0; i < N; i++) {
+      g.density[g.idx(i, N-1, k)] = g.density[g.idx(i, N-2, k)] * 0.90;
+      g.temp[g.idx(i, N-1, k)]    = g.temp[g.idx(i, N-2, k)]    * 0.90;
     }
   }
 
@@ -190,6 +197,16 @@ export class FluidSolver {
         vz[idx] += vPol_r * nz * dt;
       }
 
+      // --- Entrainment: inward pull at low altitude → narrow stem ---
+      if (this.entrainStrength > 0 && j < N * 0.50) {
+        const edx = i - cx, edz = k - cz;
+        const er = Math.sqrt(edx * edx + edz * edz) + 0.001;
+        const altFrac = j / (N * 0.50);
+        const inward = this.entrainStrength * Math.max(0, 1 - altFrac);
+        vx[idx] -= (edx / er) * inward * dt;
+        vz[idx] -= (edz / er) * inward * dt;
+      }
+
       // --- Curl-Noise Turbulence (Kolmogorov micro-scale) ---
       if (this.turbulenceStrength > 0) {
         const s = 0.15, t2 = this.turbulenceTime;

src/main.js

@@ -15,12 +15,12 @@ renderer.setClearColor(0x0a0a0f);
 
 // ---- Scene ----
 const scene = new THREE.Scene();
-scene.fog = new THREE.FogExp2(0x0a0a0f, 0.005);
+scene.fog = new THREE.FogExp2(0x0a0a0f, 0.003);
 
 // ---- Camera ----
-const camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 0.1, 500);
-camera.position.set(18, 8, 24);
-camera.lookAt(0, 5, 0);
+const camera = new THREE.PerspectiveCamera(48, window.innerWidth / window.innerHeight, 0.1, 600);
+camera.position.set(22, 10, 32);
+camera.lookAt(0, 10, 0);
 
 // ---- Post-processing (Sobel outlines + bloom) ----
 let postProcess = null;
@@ -44,8 +44,8 @@ restartBtn.addEventListener('click', () => explosion.reset());
 const clock = new THREE.Clock();
 let frameCount = 0, fpsTime = 0;
 
-const camBase = new THREE.Vector3(18, 8, 24);
-const camLook = new THREE.Vector3(0, 5, 0);
+const camBase = new THREE.Vector3(22, 10, 32);
+const camLook = new THREE.Vector3(0, 10, 0);
 
 // ---- Flash overlay (DOM-based for compatibility) ----
 const flashEl = document.createElement('div');
@@ -58,12 +58,12 @@ function animate() {
   explosion.update(dt);
   const t = explosion.time;
 
-  // Camera: slow pull-back + rise with the cloud
-  const pull = 1 + Math.min(t * 0.012, 0.2);
+  // Camera: slow pull-back + rise tracking the mushroom cloud
+  const pull = 1 + Math.min(t * 0.010, 0.18);
   camera.position.x = camBase.x * pull;
-  camera.position.y = camBase.y + Math.min(t * 0.25, 4);
+  camera.position.y = camBase.y + Math.min(t * 0.30, 8);
   camera.position.z = camBase.z * pull;
-  camLook.y = 5 + Math.min(t * 0.35, 5);
+  camLook.y = 10 + Math.min(t * 0.90, 18); // follows cap to world-y ≈ 28
   camera.lookAt(camLook);
 
   // Flash overlay