vault backup: 2025-07-14 15:06:59

03-UnrealEngine/Rendering/RenderFeature/ShaderWorldPlugin/ShaderWorld.md

@@ -1069,3 +1069,101 @@ OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZEZ"), 1);
 
 # 植被生成逻辑
 Tick() => TerrainAndSpawnablesManagement() => UpdateSpawnables() => UpdateSpawnable()
+
+
+# 碰撞Python逻辑
+
+```python
+def TickCheckWorldReady(self, dt: float) -> bool:  
+    is_shader_world_ready = self.ShaderWorldActor.WorldAndCollisionGeneratedReady()  
+    if not is_shader_world_ready:  
+        return True  
+    is_ready = self.ShaderWorldActor.CheckCollisionGeneratedReady(self.AvatarBornPosition)  
+    print("LBK --------  TickCheckWorldReady", self.FailedCheckCnt, is_ready)  
+    if is_ready:  
+        self.OnWorldMeshReady()  
+        ue.RemoveTicker(self.worldTickHander)  
+        # 等待地形物理加载完毕  
+        if self.OtherLoadFinshed:  
+            GlobalData.TimerSystem.AddTimer(1, self.ReallyStartDriving)  
+        else:  
+            self.OtherLoadFinshed = True  
+        print('LBK -------------- DrivingModeSystem: TickCheckWorldReady', GlobalData.p.pos, self.AvatarBornPosition)  
+        return False  
+    self.FailedCheckCnt += 1  
+    if self.FailedCheckCnt > self.FailedAttemptCnt:  #self.FailedAttemptCnt为40
+        self.ShaderWorldActor.RebuildWorld()  
+        self.FailedCheckCnt = 0  
+    return True
+
+# 通过LineTraceSingleForObjects检测碰撞高度是否超过5，来判断碰撞是否生成。
+def CheckCollisionGeneratedReady(self, checkPosition: ue.Vector) -> bool:  
+    HitStartLocation = checkPosition + ue.Vector(0, 0, 50000.0)  
+    HitEndLocation = checkPosition + ue.Vector(0, 0, -50000.0)  
+    hitState, hitResult = ue.KismetSystemLibrary.LineTraceSingleForObjects(  
+       self.GetWorld(),  
+       HitStartLocation,  
+       HitEndLocation,  
+       [ue.EObjectTypeQuery.ObjectTypeQuery1, ue.EObjectTypeQuery.ObjectTypeQuery13],  # Ground  
+       False,  # 是否追踪复杂碰撞  
+       [],  
+       ue.EDrawDebugTrace.ForDuration if GlobalData.IsDebugMode else ue.EDrawDebugTrace.NONE,  # 调试可视化  
+       True,  # 忽略自身  
+       ue.LinearColor(1.0, 0.0, 0.0, 1.0),  # 红色  
+       ue.LinearColor(0.0, 1.0, 0.0, 1.0),  # 绿色  
+       20.0  # 调试线条持续时间  
+    )  
+    if not hitState:  
+       return False  
+    # TODO LBK 这个射线检测的方式不太准确，那个物理生成，会从平面开始  
+    return hitResult.Location.Z > 5.0
+```
+
+```c++
+bool AShaderWorldActor::WorldAndCollisionGeneratedReady()
+{
+	if (!WorldGeneratedAndReady())
+		return false;
+	if (!CollisionShareable.IsValid())
+		return false;
+
+	FScopeLock CollisionMeshArrayAccess(CollisionMeshAccessLock.Get());
+
+	// 1. 必须有碰撞布局
+	if (CollisionShareable->GroundCollisionLayout.Num() == 0)
+		return false;
+
+	// 2. 检查所有Patch都ready
+	for (const auto& Pair : CollisionShareable->GroundCollisionLayout)
+	{
+		const FIntVector& Loc = Pair.Key;
+		const FName& CollisionName = Pair.Value;
+
+		// Patch必须存在
+		if (!CollisionMesh.Contains(CollisionName))
+			return false;
+
+		// Patch必须在已用集合
+		if (!CollisionShareable->UsedCollisionMesh.Contains(CollisionName))
+			return false;
+
+		// Patch必须ReadBack完成
+		const FCollisionMeshElement& CollisionElement = *CollisionMesh.Find(CollisionName);
+		if (!CollisionElement.ReadBackCompletion.IsValid() || !(*CollisionElement.ReadBackCompletion.Get()))
+			return false;
+
+		// Patch不能在待处理队列
+		if (CollisionReadToProcess.Contains(CollisionName))
+			return false;
+		if (!UsedCollisionMesh.Contains(CollisionName))
+			return false;
+
+		// Patch不能在工作队列
+		for (const auto& WQ : CollisionWorkQueue)
+			if (WQ.MeshID == CollisionName)
+				return false;
+	}
+
+	return true;
+}
+```