A problem of getting XZ coordinates

[yoyotvyoo]

Hello,

I am trying the code in this tutorial http://www.ogre3d.org/tikiwiki/Get+XZ+coordinates and here is my code.

Code: Select all

MeshManager::getSingleton().createPlane(
		"ground", ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, 
		mPlane, 
		1500, 1500,
		20, 20,
		true,
		1,
		5, 5,
		Vector3::UNIT_Z
		);
Entity *planeEntity= mSceneMgr->createEntity("Ground", "ground"); 
mSceneMgr->getRootSceneNode()->createChildSceneNode()->attachObject(planeEntity); 

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mCamera = mSceneMgr->createCamera("Camera");
mCamera->setPosition(Ogre::Vector3(0, 700, 800));
mCamera->lookAt(Ogre::Vector3(0, 0, 0));
mCamera->setNearClipDistance(5);

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Ray mRay = mTrayMgr->getCursorRay(mCamera);
std::pair<bool, Real> result = mRay.intersects(mPlane);
 
	if (result.first)
	{
		Vector3 point= mRay.getPoint(result.second);
	}

The problem is that when I click out of the plane, I can still get the intersection result. It means 'result.first' returns true. One of my guess is that the plane is only rendered partly, so the cursor ray can intersect the plane even if we cannot see the plane there. But I am not too sure about this guess. How should I understand this code? Thanks.