• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
cozzie

Strange rotation sympton, aabb extents (with video)

27 posts in this topic

Thanks, I understand the logic and just debugged quite a bit again.

I saved the result per plane for 3 situations (without stopping the loop), fully inside, outside and intersecting.

 

Mesh fully inside = OK:

 

Plane: 0
d > s: Return INSIDE
Plane: 1
d > s: Return INSIDE
Plane: 2
d > s: Return INSIDE
Plane: 3
d > s: Return INSIDE
Plane: 4
d > s: Return INSIDE
Plane: 5
d > s: Return INSIDE

 

'Live" it will stop after the 1st plane returning fully INSIDE.

 

Mesh intersecting = Not OK

 

Plane: 0
d > s: Return INSIDE

Plane: 1

Plane: 2
d > s: Return INSIDE

Plane: 3
d > s: Return INSIDE

Plane: 4
d > s: Return INSIDE

Plane: 5
d > s: Return INSIDE

 

'Live' it will stop after the 1st plane returning fully INSIDE, although it isn't, based on the 2nd plane.

 

Mesh fully outside = Not OK

The results is that only 1 plane returns 'outside'.

 

Plane: 0
d > s: Return INSIDE
Plane: 1
d > s: Return INSIDE
Plane: 2
d < -s: Return OUTSIDE
Plane: 3
d > s: Return INSIDE
Plane: 4
d > s: Return INSIDE
Plane: 5
d > s: Return INSIDE

 

Will be debugging more smile.png
 

Most likely it has to do with calculating 's', since it's always 4.9 or 5.0f, which is strange..

Edited by cozzie
0

Share this post


Link to post
Share on other sites
I can't keep saying this or I'll bore everyone, but you haven't got the logic right.

The only value you can return from inside the loop is OUTSIDE, when a plane rejects the box. If any plane intersected the box return INTERSECT after checking all the planes. Otherwise return INSIDE.

You seem to expect all planes to return outside if the box is outside the frustum. That's not right. It only takes one to reject it.
0

Share this post


Link to post
Share on other sites

Sorry, I was blind staring on this approach:

 

"If the box centre is c, the box axes are ax, ay, az, and the sizes on each axis are sx, sy, sz, then:

d = dot(c, plane)
s = abs(dot(ax, plane)) * sx + abs(dot(ay, plane)) * sy + abs(dot(az, plane)) * sz

If d > s not culled
If d < -s culled
Otherwise intersects."

 

Got it all working now, with the code below.

Just drawn it out (litterly with a pretty ugly drawing :)) to make sure I get it:

- if the OBB is behind/ in negative halfspace of a plane, directly return outside

(since the OBB cannot be behind more then one plane)

- because the OBB can intersect with more then one plane, I just mark that I found a plane where it intersected

- in the end I check if there were any planes that intersected, if so, return intersected

- if there were no planes intersecting and it didn't return outside, then it's definately fully inside

- it's not possible to determine if it's completely inside without checking all planes

- even if I didn't want a different result for intersecting and fully inside, I would need to go through all planes

(unless the object is behind one of the planes)

int CD3dcam::OBBInFrustum(BOUNDINGBOX *pBoundingBox, D3DXMATRIX *pWorldMatrix)
{
	int _result = 99;

	mAx = D3DXVECTOR3(pWorldMatrix->_11, pWorldMatrix->_12, pWorldMatrix->_13);
	mAy = D3DXVECTOR3(pWorldMatrix->_21, pWorldMatrix->_22, pWorldMatrix->_23);
	mAz = D3DXVECTOR3(pWorldMatrix->_31, pWorldMatrix->_32, pWorldMatrix->_33);

	float d, s;

	for(int i=0;i<6;++i)
	{
		d = D3DXPlaneDotCoord(&mFrustumPlane[i], &pBoundingBox->OBBcenter);

		s = fabs	(D3DXVec3Dot(&mAx, &D3DXVECTOR3(mFrustumPlane[i].a, mFrustumPlane[i].b, mFrustumPlane[i].c)) * pBoundingBox->OBBsize.x / 2.0f) +
			fabs	(D3DXVec3Dot(&mAy, &D3DXVECTOR3(mFrustumPlane[i].a, mFrustumPlane[i].b, mFrustumPlane[i].c)) * pBoundingBox->OBBsize.y / 2.0f) +
			fabs	(D3DXVec3Dot(&mAz, &D3DXVECTOR3(mFrustumPlane[i].a, mFrustumPlane[i].b, mFrustumPlane[i].c)) * pBoundingBox->OBBsize.z / 2.0f);

		if(d < -s) return OUTSIDE;
		if(d+ -s < 0) _result = INTERSECT;	
	}
	if(_result == INTERSECT) return INTERSECT;
	else return INSIDE;
}

There's possibly some optimization possible, but finally it all works :)

Thanks for all the help and blind staring now and then..

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0