3d mouse coords.

OpenGL OpenGL: Advanced Coding
1

I need to transform the mouse coords recieved from windows messages into 3d world coords. Has anyone done this? thanks

2

Check this page http://www.opengl.org/developers/faqs/technical/selection.htm , it has some information.

Nate Miller

3

To get your 3D coords, you need to get the depth-value of your x-y position. Use glReadPixels with GL_DEPTH_COMPONENT for this.
Then use gluUnproject to convert from this x-y-z-screen coordinates to your world coordinates.
Have search on gluUnproject on this forum, and you will find some posts.

Kilam.

4

Thanks for the page nate. It seems to be working, except the retrieved mouse coords seem to be rather high. Such as -89, 41, -94. This doesnt seem to correct when im clicking on an object thats no more then 1x1 unit. I use this.

float y;
float winz;
GLdouble wx, wy, wz;
GLdouble wx2, wy2, wz2;

y = vp[3] - MPos.y;

gluUnProject((GLdouble)MPos.x, (GLdouble)y, (GLdouble)0.0, mv, pro, vp, &wx, &wy, &wz);

gluUnProject((GLdouble)MPos.x, (GLdouble)y, (GLdouble)1.0, mv, pro, vp, &wx2, &wy2, &wz2);

CVector nearp = CVector(wx, wy, wz);
CVector farp = CVector(wx2, wy2, wz2);
CVector ray = nearp - farp;

It just doesnt seem that these values are correct. thanks.

~ Chris