unity中htc vive射线与UI碰撞检测-graphcs.Raycast()_htcvive 相机射线检测

// htc vive CanvasRaycastMethod 
/*
继承关系：IRaycastMethod 接口<-- BaseRaycastMetod抽象类 <-- CanvasRaycastMethod
重写Raycast(Ray ray, float distance, List<RaycastResult> raycastResults)
*/
public override void Raycast(Ray ray, float distance, List<RaycastResult> raycastResults)
{
	var tempCanvases = ListPool<ICanvasRaycastTarget>.Get();
	tempCanvases.AddRange(canvases);
	for (int i = tempCanvases.Count - 1; i >= 0; --i)
	{
		var target = tempCanvases[i];
		if (target == null || !target.enabled) { continue; }
		Raycast(target.canvas, target.ignoreReversedGraphics, ray, distance, raycaster, raycastResults);// raycaster from BaseRaycastMetod
	}
	ListPool<ICanvasRaycastTarget>.Release(tempCanvases);
}
 
public static void Raycast(Canvas canvas, bool ignoreReversedGraphics, Ray ray, float distance, Pointer3DRaycaster raycaster, List<RaycastResult> raycastResults)
{
	if (canvas == null) { return; }
 
	var eventCamera = raycaster.eventCamera;  // 获取相机事件   
	var screenCenterPoint = Pointer3DInputModule.ScreenCenterPoint;  // 获得屏幕的中心点
	var graphics = GraphicRegistry.GetGraphicsForCanvas(canvas); // 获取canvas中的Graphic列表， UI中图形继承的Graphic
 
	// Pointer3DRaycaster should set tje eventCamera to correct position
 
	for (int i = 0; i < graphics.Count; ++i)
	{
		var graphic = graphics[i];
 
		// -1 means it hasn't been processed by the canvas, which means it isn't actually drawn
		if (graphic.depth == -1 || !graphic.raycastTarget) { continue; }
 
		if (!RectTransformUtility.RectangleContainsScreenPoint(graphic.rectTransform, screenCenterPoint, eventCamera)) { continue; }
// 如果射线方向和graphic法线方向夹角大于90或者大于-90，说明只能看到线或者graphic的背面
		if (ignoreReversedGraphics && Vector3.Dot(ray.direction, graphic.transform.forward) <= 0f) { continue; }
// 如果是有效位置返回真，否则返回假
		if (!graphic.Raycast(screenCenterPoint, eventCamera)) { continue; }
 
		//var dist = Vector3.Dot(transForward, trans.position - ray.origin) / Vector3.Dot(transForward, ray.direction);
		float dist;
		// 法线加点绘制平面  返回沿射线与平面相交的距离
		new Plane(graphic.transform.forward, graphic.transform.position).Raycast(ray, out dist);
		if (dist > distance) { continue; }
 
		raycastResults.Add(new RaycastResult
		{
			gameObject = graphic.gameObject,
			module = raycaster,
			distance = dist,
			worldPosition = ray.GetPoint(dist),
			worldNormal = -graphic.transform.forward,
			screenPosition = screenCenterPoint,
			index = raycastResults.Count,
			depth = graphic.depth,
			sortingLayer = canvas.sortingLayerID,
			sortingOrder = canvas.sortingOrder
		});
	}
}