[SOLVED] distance camera - intersection from ray

[emmanuel1359]

hello,

i would like to do an action if i am close from the object in front of me:
so the code would be:

Ray ray = OgreFramework::getSingletonPtr()->m_pCamera->getCameraToViewportRay(0.5, 0.5);
Vector3 intersection;
Real scale = mVolumeRoot->getChunkParameters()->scale;
bool intersects = mVolumeRoot->getChunkParameters()->src->getFirstRayIntersection(ray, intersection, scale);

if (intersects and intersection.distance(OgreFramework::getSingletonPtr()->m_pCamera->getDerivedPosition()) < 10)

but this never raises
i'm supposed to be at the same position that the camera, and the point of intersection is "intersection"

must I substract the vectors ?

[areay]

What has your debugging turned up?

Is 'bool intersects' being raised at all?

If so, what is the value of the distance?

[emmanuel1359]

there the code added to log values:

Code: Select all

**************************************************
	Vector3 intersection;
	Real scale = mVolumeRoot->getChunkParameters()->scale;
	bool intersects = mVolumeRoot->getChunkParameters()->src->getFirstRayIntersection(ray, intersection, scale);

OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("m_pCamera->getDerivedPosition = ")+Ogre::StringConverter::toString(OgreFramework::getSingletonPtr()->m_pCamera->getDerivedPosition()));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("intersection ")+Ogre::StringConverter::toString(intersection ));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("diff ")+Ogre::StringConverter::toString(intersection - OgreFramework::getSingletonPtr()->m_pCamera->getDerivedPosition()));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("distance diff ")+Ogre::StringConverter::toString(intersection.distance(OgreFramework::getSingletonPtr()->m_pCamera->getDerivedPosition())));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("intersects ")+Ogre::StringConverter::toString(intersects));
**************************************************

And there the log:

Code: Select all

**************************************************
20:43:13: m_pCamera->getDerivedPosition = 2808.64 2488.75 3383.8
20:43:13: intersection 280.514 217.737 292.698
20:43:13: diff -2528.13 -2271.01 -3091.1
20:43:13: distance diff 4593.89
20:43:13: intersects true
20:43:15: m_pCamera->getDerivedPosition = 2809.94 2336.77 3160.65
20:43:15: intersection 282.222 218.113 292.525
20:43:15: diff -2527.72 -2118.66 -2868.12
20:43:15: distance diff 4370.83
20:43:15: intersects true
20:43:16: m_pCamera->getDerivedPosition = 2818.75 2238.82 3011.08
20:43:16: intersection 282.407 218.226 292.419
20:43:16: diff -2536.35 -2020.6 -2718.66
20:43:16: distance diff 4231.67
20:43:16: intersects true
20:43:21: m_pCamera->getDerivedPosition = 2823.99 2185.82 2928.82
20:43:21: intersection 282.433 218.266 292.385
20:43:21: diff -2541.56 -1967.56 -2636.43
20:43:21: distance diff 4157.11
20:43:21: intersects true
20:43:23: Main loop quit
20:43:23: Shutdown OGRE...
**************************************************

thanks !

[emmanuel1359]

i tried to change
getDerivedPosition
to
getRealPosition

what is the difference ?

because I wonder if there is a problem with local and world coordinate

[emmanuel1359]

well, that's better, dividing the camera by the scale factor:

Code: Select all

OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("m_pCamera->getPosition = ")+Ogre::StringConverter::toString(OgreFramework::getSingletonPtr()->m_pCamera->getPosition() / scale));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("intersection ")+Ogre::StringConverter::toString(intersection ));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("diff ")+Ogre::StringConverter::toString(intersection - OgreFramework::getSingletonPtr()->m_pCamera->getPosition() / scale));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("distance diff ")+Ogre::StringConverter::toString(intersection.distance(OgreFramework::getSingletonPtr()->m_pCamera->getPosition() / scale)));
OgreFramework::getSingletonPtr()->m_pLog->logMessage(String("intersects ")+Ogre::StringConverter::toString(intersects));

Code: Select all

1:24:49: m_pCamera->getPosition = 326.4 270 326.4
21:24:49: intersection 281.27 204.298 158.838
21:24:49: diff -45.1301 -65.7016 -167.562
21:24:49: distance diff 185.554
21:24:49: intersects true
21:24:50: m_pCamera->getPosition = 326.4 270 326.4
21:24:50: intersection 299.523 193.809 182.411
21:24:50: diff -26.8768 -76.1915 -143.989
21:24:50: distance diff 165.107
21:24:50: intersects true
21:24:51: m_pCamera->getPosition = 326.4 270 326.4
21:24:51: intersection 308.408 193.623 203.585
21:24:51: diff -17.992 -76.3771 -122.815
21:24:51: distance diff 145.742
21:24:51: intersects true
21:24:51: m_pCamera->getPosition = 326.4 270 326.4
21:24:51: intersection 312.502 194.412 216.329
21:24:51: diff -13.8981 -75.5878 -110.071
21:24:51: distance diff 134.247
21:24:51: intersects true
21:24:53: m_pCamera->getPosition = 312.516 284.698 346.429
21:24:53: intersection 294.24 221.458 292.887
21:24:53: diff -18.2758 -63.2403 -53.5429
21:24:53: distance diff 84.8539
21:24:53: intersects true
21:24:55: m_pCamera->getPosition = 304.817 264.647 330.405
21:24:55: intersection 285.141 218.285 292.559
21:24:55: diff -19.6761 -46.362 -37.8459
21:24:55: distance diff 62.9992
21:24:55: intersects true
21:24:55: m_pCamera->getPosition = 296.422 246.286 315.504
21:24:55: intersection 281.83 218.192 292.44
21:24:55: diff -14.5921 -28.0942 -23.0644
21:24:55: distance diff 39.1686
21:24:55: intersects true
21:24:57: m_pCamera->getPosition = 280.143 221.736 293.224
21:24:57: intersection 278.369 219.548 290.939
21:24:57: diff -1.77374 -2.18793 -2.28525
21:24:58: distance diff 3.62706
21:24:58: intersects true
21:25:01: m_pCamera->getPosition = 275.251 219.672 290.652
21:25:01: intersection 275.209 219.654 290.625
21:25:01: diff -0.0411682 -0.0187225 -0.0271912
21:25:01: distance diff 0.0527704
21:25:01: intersects true

[scrawl]

i tried to change
getDerivedPosition
to
getRealPosition

what is the difference ?

See the API docs:

const Vector3& Ogre::Camera::getRealPosition ( void ) const
Gets the real world position of the camera, including any translation inherited from a node attachment.

const Vector3& Ogre::Camera::getDerivedPosition ( void ) const
Gets the derived position of the camera, including any translation inherited from a node attachment and reflection matrix.

So the only difference is when a reflection matrix is concerned, e.g. using the camera for a plane reflection, which I assume you're not doing,

[spacegaier]

@emmanuel1359: Please use the "

Code: Select all

" tags for actual coding or long log output lists. Thank you.

[emmanuel1359]

ok, i'll use it !

thanks spacegaier



EDIT: the better way is:

Code: Select all

	Vector3 intersection;
	Real scale = mVolumeRoot->getChunkParameters()->scale;
	bool intersects = mVolumeRoot->getChunkParameters()->src->getFirstRayIntersection(ray, intersection, scale);

	if (intersects and OgreFramework::getSingletonPtr()->m_pCamera->getPosition().distance(intersection * scale) < 30)
	{
}

[areay]

So you've solved it?

[emmanuel1359]

yes, how to add [solved]  in the main title ?

[spacegaier]

yes, how to add [solved]  in the main title ?

By editing your first post in the thread. This gives you the option to change the title for the whole thread.