From f8734dce88161564ea36acefedff5ef71c05f737 Mon Sep 17 00:00:00 2001
From: n30nex <blushellneon@outlook.com>
Date: Sun, 27 Sep 2026 00:18:24 -0400
Subject: [PATCH] Bound GPU presentation cost without dropping packet motion

---
 web/src/gpuEffects.ts     | 12 +++++++++---
 web/src/packetAnimator.ts |  3 +--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/web/src/gpuEffects.ts b/web/src/gpuEffects.ts
index a355431..4e1d430 100644
--- a/web/src/gpuEffects.ts
+++ b/web/src/gpuEffects.ts
@@ -146,21 +146,27 @@ export class GPUEffects {
 
 export function mapEffects(map: LibreMap) {
   const batch=new GPUEffects(); let activeGL: WebGL2RenderingContext|undefined;
-  let lastInk=false, requestedAt=0, slowFrames=0, budgetFallback=false;
+  let lastInk=false, requestedAt=0, slowFrames=0, lastFrameAt=0, slowPresentationFrames=0, budgetFallback=false;
   const measure=()=>{
     if(!requestedAt)return;
     const elapsed=performance.now()-requestedAt;requestedAt=0;
     slowFrames=elapsed>80?slowFrames+1:Math.max(0,slowFrames-1);
     if(slowFrames>=3)budgetFallback=true;
   };
-  const retry=()=>{budgetFallback=false;slowFrames=0;requestedAt=0;};
+  const retry=()=>{budgetFallback=false;slowFrames=0;slowPresentationFrames=0;lastFrameAt=0;requestedAt=0;};
   map.on('render',measure);map.on('moveend',retry);
   const layer: CustomLayerInterface={id:'live-packet-effects',type:'custom',renderingMode:'2d',onAdd(_map,gl){activeGL=gl as WebGL2RenderingContext;batch.initialize(activeGL);},render(){batch.draw();},onRemove(){batch.dispose();}};
   const attach=()=>{if(map.isStyleLoaded?.() && !map.getLayer(layer.id)) map.addLayer(layer);};
   const lost=()=>batch.dispose();
   const restored=()=>{if(activeGL)batch.initialize(activeGL);attach();map.triggerRepaint();};
   map.on('load',attach); map.on('idle',attach); map.on('styledata',attach); map.on('webglcontextlost',lost); map.on('webglcontextrestored',restored); attach();
-  return {batch,prepare:()=>batch.setEnabled(displayPreferences().quality !== 'economy' && (!budgetFallback || displayPreferences().quality === 'high')),flush:()=>{
+  return {batch,prepare:()=>{
+    const now=performance.now();
+    if(lastInk&&lastFrameAt)slowPresentationFrames=now-lastFrameAt>80?slowPresentationFrames+1:Math.max(0,slowPresentationFrames-1);
+    if(slowPresentationFrames>=3)budgetFallback=true;
+    lastFrameAt=now;
+    batch.setEnabled(displayPreferences().quality !== 'economy' && !budgetFallback);
+  },flush:()=>{
     const ink=batch.ready&&batch.hasInk;
     // A stationary faded trail does not require rerasterizing the whole basemap.
     if(ink||lastInk){if(!requestedAt)requestedAt=performance.now();map.triggerRepaint();}
diff --git a/web/src/packetAnimator.ts b/web/src/packetAnimator.ts
index aa4781e..a194afd 100644
--- a/web/src/packetAnimator.ts
+++ b/web/src/packetAnimator.ts
@@ -396,6 +396,7 @@ export class PacketAnimator {
       this.frameId = 0;
       this.residueTimer = undefined;
       this.clearCanvas();
+      this.gpu.batch.clear(); this.gpu.flush();
       this.clearResidueCanvas();
     } else {
       this.requestFrame();
@@ -1087,8 +1088,6 @@ export class PacketAnimator {
   }
 
   private clearCanvas(): void {
-    this.gpu.batch.clear();
-    this.gpu.flush();
     const width = this.canvas.width / this.dpr;
     const height = this.canvas.height / this.dpr;
     this.context.clearRect(0, 0, width, height);