• 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
Code-R

Extracting 6 Frustum Planes from camera Position, Direction, FOV And Viewing Distance

6 posts in this topic

"from camera Position, Direction, FOV And Viewing Distance", not the MVP matrix. I've googled ;). thanx for the effort anyway!
0

Share this post


Link to post
Share on other sites
Got it. You can also do it from the information you have using trig. For this you'll need the fov in both directions, so you'll need to calculate one from the other (horizontal from vertical or vice versa).

The normals to the near and far planes are simply +/- the view direction vector. The distances can be found using your camera position and a little vector math.

The normals for the other planes can be found using the sin and cos of half your horizontal and vertical fov, and your camera's local frame. Then dot the normals with the camera position to find the distances.

Note that the info you mentioned doesn't uniquely determine a frustum - you need a complete local frame, that is, an up or side vector in addition to the direction vector. I assume you have that available.

I've actually written this code before and have it lying around on my hard drive somewhere. If you get stuck on the implementation, let me know and I'll find the code and post it.
0

Share this post


Link to post
Share on other sites
Quote:
how can i calculate one fov from the other?
Ok, let's see if I remember this...

We'll use the following variable names:

hFov = horizontal fov/2
vFov = vertical fov/2
w = screen width/2
h = screen height/2
d = distance to screen
aspect = w/h

Next, note that:

tan(hFov) = w/d
tan(vFov) = h/d

Let's say we know hFov and we want to find vFov.

tan(hFov) = w/d
(w/d)/aspect = (w/d)/(w/h) = (w/d)(h/w) = wh/dw = h/d = tan(vFov)

Therefore:

vFov = atan(tan(hFov)/aspect)

If we know vFov and we want to find hFov:

tan(vFov) = h/d
(h/d)aspect = (h/d)(w/h) = hw/dh = w/d = tan(hFov)

And:

hFov = atan(tan(vFov)aspect)

So all you need is the aspect ratio and either the horizontal or vertical fields of view. Don't forget to add the factors of 2 back into the equations.

Anyway, I think I got that right - if I made any errors I'm sure someone will point them out.
0

Share this post


Link to post
Share on other sites
Extracted from my own code (thats works wells) :


void CFrustum::CalculateFrustum(const CCamera &rCamera)
{
// We need 6 clipping planes for the standard frustum, more the additional planes
// Provided by the user
ClearPlanes();
const vector<CPlane*> &vecUserPlanes = rCamera.GetClipPlanesVector();
m_clipPlanes.reserve(6 + vecUserPlanes.size());

uint32 i, ip;
CMat4x4 matView = ((CCamera&)rCamera).GetViewMatrix();
CMat4x4 matProj = ((CCamera&)rCamera).GetProjectionMatrix();

// Calculate half Width and Height at near plane distance
float fHalfFovTan = tanf(PHSR_DEGREE_TO_RADIAN(rCamera.GetFieldOfView() / 2.0f));
float fNear = rCamera.GetNearZ();
float fHalfW = fHalfFovTan * fNear;
float fHalfH = fHalfW / rCamera.GetAspectRatio();

// Get orientation of the frustum
CVector3 vIn, vLeft, vUp;
vIn = matView.GetIn();
vLeft = matView.GetLeft();
vUp = matView.GetUp();

// Calculate scaled vectors descibing the VF
float fZRatio = (rCamera.GetFarZ()) / rCamera.GetNearZ();
CVector3 kDScaled = vIn * rCamera.GetNearZ();
CVector3 kLScaled = vLeft * fHalfW;
CVector3 kUScaled = vUp * fHalfH;

// Calculate the four near corners
m_vFrustumCorner[0] = kDScaled - kLScaled - kUScaled;
m_vFrustumCorner[1] = kDScaled - kLScaled + kUScaled;
m_vFrustumCorner[2] = kDScaled + kLScaled + kUScaled;
m_vFrustumCorner[3] = kDScaled + kLScaled - kUScaled;

// Deduce the four far corners
for (i = 0, ip = 4; i < 4; i++, ip++)
{
m_vFrustumCorner[ip] = rCamera.GetPosition() + m_vFrustumCorner[i] * fZRatio;
m_vFrustumCorner[i] += rCamera.GetPosition();
}

////
// Calculate clipping planes from corners
////
CPlane *pPlane = NULL;

// Bottom
m_clipPlanes.push_back(new CPlane(m_vFrustumCorner[0], m_vFrustumCorner[4], m_vFrustumCorner[3]));

// Top
pPlane = new CPlane(m_vFrustumCorner[1], m_vFrustumCorner[5], m_vFrustumCorner[2]);
m_clipPlanes.push_back(pPlane);
pPlane->Reverse();

// Left
m_clipPlanes.push_back(new CPlane(m_vFrustumCorner[0], m_vFrustumCorner[1], m_vFrustumCorner[4]));

// Right
pPlane = new CPlane(m_vFrustumCorner[3], m_vFrustumCorner[2], m_vFrustumCorner[7]);
m_clipPlanes.push_back(pPlane);
pPlane->Reverse();

// Near
pPlane = new CPlane(m_vFrustumCorner[0], m_vFrustumCorner[1], m_vFrustumCorner[3]);
m_clipPlanes.push_back(pPlane);
pPlane->Reverse();

// Far
m_clipPlanes.push_back(new CPlane(m_vFrustumCorner[4], m_vFrustumCorner[5], m_vFrustumCorner[7]));

// Add clipping planes provided by the user
for (i = 0 ; i < vecUserPlanes.size() ; i++)
{
// Use copy constructor
m_clipPlanes.push_back(new CPlane(*vecUserPlanes[i]));
}
}

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