• 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

Ray Picking - Need help.

1 post in this topic


I'm trying for long time to implement picking ray.
I read lots of tutorials online, but still did not managed to make to work properly.

I'm created the near/far points using unproject method ( that works exactly the same as gluunproject does).
then I created the ray and check for intersection with the bounding box.

For visual reference I draw the ray. it looks like the ray does not comes out from the mouse cursor toward the scene.

Please help me in here.


int UnProject(float winx, float winy, float winz, const Matrix4f *modelview, const Matrix4f *projection, int viewport[4], Vector3f *objectCoordinate)
const m44<f32>& inverseVP = (*projection * *modelview).inverse();
Vector4f in( (winx-(float)viewport[0])/(float)viewport[2]*2.0-1.0,
1.0 );
Vector4f out = inverseVP * in;
if(out.w == 0.0f)
return 0;
return 1;

void sRay::Create( const int& MouseX,
const int& MouseY,
NS_CAMERA::sCamera* pCamera )
int viewport[4] = {0,0,WINDOW_WIDTH, WINDOW_HIGHT };
Vector3f _near;
Vector3f _far;
UnProject(MouseX, viewport[3]-MouseY,0,&pCamera->GetViewMatrix(),&pCamera->GetProjectionMatrix(),viewport,&_near); // get coords
UnProject(MouseX, viewport[3]-MouseY,1,&pCamera->GetViewMatrix(),&pCamera->GetProjectionMatrix(),viewport,&_far);
m_Direction = (_far - _near).normalize();
m_Origen = *pCamera->GetCameraPos();

void sRay::Render( NS_CAMERA::sCamera* pCamera )
Vector3f p0 = m_Origen;
Vector3f p1 = pCamera->fZFar *m_Direction;
// Drawing the line using OGL...

Share this post

Link to post
Share on other sites
Maybe visual reference will help to understand the problem:

the ray settings are:
m_Direction = _far - *pCamera->GetCameraPos();
m_Origen = *pCamera->GetCameraPos();

in here I tried different settings, where the most noticeable thing is that the blue dot is always on the center of the screen.

m_Direction = _far - _near;
m_Origen = *pCamera->GetCameraPos();

The blue dot. is a sphere at the far plane ( p = m_Origen + m_Direction * pCamera->GetFar() ).

I get intersection only when the blue dot is on the bounding box of the teapot.
I want to create the effect, where the ray is injected from the mouse toward the scene.

What am I missing ?

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