Merge pull request #8169 from RaananW/cannonGoFlat

Cannon first frame body transformation init

dist/preview release/what's new.md

@@ -195,6 +195,7 @@
 - Make sure bone matrices are up to date when calling `TransformNode.attachToBone` ([Popov72](https://github.com/Popov72))
 - Fix display problem with transparent objects and SSAO2 pipeline (bug in the `GeometryBufferRenderer`) ([Popov72](https://github.com/Popov72))
 - Fixed `Sound` not accepting a `TransformNode` as a source for spatial sound ([Poolminer](https://github.com/Poolminer))
+- Fixed an issue with transformation set after physics body was created using cannon.js ([#7928](https://github.com/BabylonJS/Babylon.js/issues/7928)) ([RaananW](https://github.com/RaananW))
 - Fix bug when using `ShadowOnlyMaterial` with Cascaded Shadow Map and `autoCalcDepthBounds` is `true` ([Popov72](https://github.com/Popov72))
 
 ## Breaking changes

src/Physics/Plugins/cannonJSPlugin.ts

@@ -22,6 +22,7 @@ export class CannonJSPlugin implements IPhysicsEnginePlugin {
     private _cannonRaycastResult: any;
     private _raycastResult: PhysicsRaycastResult;
     private _physicsBodysToRemoveAfterStep = new Array<any>();
+    private _firstFrame = true;
     //See https://github.com/schteppe/CANNON.js/blob/gh-pages/demos/collisionFilter.html
     public BJSCANNON: any;
 
@@ -53,7 +54,14 @@ export class CannonJSPlugin implements IPhysicsEnginePlugin {
         return this._fixedTimeStep;
     }
 
-    public executeStep(delta: number): void {
+    public executeStep(delta: number, impostors: Array<PhysicsImpostor>): void {
+        // due to cannon's architecture, the first frame's before-step is skipped.
+        if (this._firstFrame) {
+            this._firstFrame = false;
+            for (const impostor of impostors) {
+                impostor.beforeStep();
+            }
+        }
         this.world.step(this._useDeltaForWorldStep ? delta : this._fixedTimeStep);
         this._removeMarkedPhysicsBodiesFromWorld();
     }