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InstanceDataGetHitInstanceIndex Method

GetHitInstanceIndex returns index of the instance that was hit in hit testing (defined by hitBounds). The method retuns -1 if hitBounds is not found (was not hit).

Namespace: Ab3d.DirectX
Assembly: Ab3d.DXEngine.Wpf (in Ab3d.DXEngine.Wpf.dll) Version: 7.1.9105.2048
Syntax
C#
Copy
public static int GetHitInstanceIndex(
	Rect3D hitBounds,
	Rect3D instancedMeshBounds,
	InstanceData[] instanceData,
	bool useOnlyMatrixTranslation = false
)

Parameters

hitBounds  Rect3D
Rect3D that defines the bounds of the hit model
instancedMeshBounds  Rect3D
Rect3D that defines the bounds of the MeshGeometry3D that was used in object instancing
instanceData  InstanceData
array of InstanceData
useOnlyMatrixTranslation  Boolean  (Optional)
true if World matrices in instanceData define only translation (OffsetX, OffsetY, OffsetZ) and no scale or rotation (in this case a faster code path can be taken); if false (by default) a full matrix transformation is executed on each position

Return Value

Int32
index of the instance that was hit or -1 if no instance is hit
Remarks

The following code shows a method that changes the color of the instance with mouse over it. The following method is called from Ab3d.Utilities.EventManager3D after is is subscribed to MouseMove event.

Example
private void VisualEventSource3DOnMouseMove(object sender, Mouse3DEventArgs e) { if (e.RayHitResult == null || e.RayHitResult.ModelHit == null) return; // This should not happen, but it is safer to have this check anyway // Check if this model was already selected if (ReferenceEquals(e.RayHitResult.ModelHit, _lastHitModel)) return; var hitBounds = e.RayHitResult.ModelHit.Bounds; var hitInstanceIndex = InstanceData.GetHitInstanceIndex(hitBounds, _instanceMeshGeometry3D.Bounds, _instancedData, useOnlyMatrixTranslation: true); if (hitInstanceIndex == -1) return; // We did not find the instance index // Set color of hit object to Red _instancedData[hitInstanceIndex].DiffuseColor = Colors.Red.ToColor4(); // After each change of instaceData we need to call Update method on InstancedMeshGeometryVisual3D _instancedMeshGeometryVisual3D.Update(); }
See Also