Jump to content
  • Advertisement
Sign in to follow this  

[SOLVED] Screen space to object space

This topic is 3499 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hey guys, I am looking for a way to convert a screen spaced 2d vector to a object space 2d vector. Basically I have a gui that can be rotated and what to be able to quickly tell if the mouse is inside the object. Currently I am simply check the x, x+width, y, +height. However once rotation comes into play these, of course, no longer work. I have heard from several people that gluUnproject will do what I need which ha led me to build my own unproject function, as I needed to use floats and not doubles. The code below tends to give me skewed results. With no rotation the Y axis is mirrored over the x axis, and when rotated 90 degrees the x axis becomes skewed. Any ideas??
 void Window::Unproject( float winx, float winy, float* p, int* view, float* ox, float* oy ){
	nv::vec4<float> in = nv::vec4<float>(	((winx - view[0]) * 2.0) / view[2] - 1.0,
        ((winy - view[1]) * 2.0) / view[3] - 1.0,						-1.0,											1.0 );

	nv::matrix4<float> proj;
	proj.set_value( p );

	nv::vec4<float> ret = inverse( proj * Modelview ) * in;

	if( ret.w == 0.0 )

	*ox = ret.x / ret.w;
	*oy = ret.y / ret.w;

SOLVED: Inverted the in.y and it seems to work fine now.. [Edited by - cherryyosh on April 22, 2009 6:57:47 PM]

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!