How to use gluUnProject draw 3D with Opengl

Question

0.00/5 (No votes)

See more:

nobody seems to understand my code.
sorry, because I post new questions while no one has answered the question before
I have read about gluUnProject Nehe lession 13 but I do not understand.
giatuan asked about the mouse in OpenGL.
Is Z depth?
I understand Z points out of the screen towards me
How can I get value Z mouse?
suppose I drew three axes x, y, z
My purpose is to draw polygon in 3D
help me

Posted 8-Jul-11 19:22pm

Phuong_

Updated 8-Jul-11 19:35pm

v2

Add a Solution

Comments

harish85 9-Jul-11 2:13am

Use glReadPixels to get depth...Can you post some code?

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

harish85 · Answer 1 · 2011-07-08T20:19:00

See if this helps you - Googled
http://www.idevgames.com/forums/thread-6400.html[^]

Check this for code -

http://nehe.gamedev.net/data/articles/article.asp?article=13[^]

I am copying the code from that link what you need, you are converting mouse (X,Y)
points to a space(X,Y,Z) GL coordinates -

CVector3 GetOGLPos(int x, int y)
{
GLint viewport[4];
GLdouble modelview[16];
GLdouble projection[16];
GLfloat winX, winY, winZ;
GLdouble posX, posY, posZ;
glGetDoublev( GL_MODELVIEW_MATRIX, modelview );
glGetDoublev( GL_PROJECTION_MATRIX, projection );
glGetIntegerv( GL_VIEWPORT, viewport );
winX = (float)x;
winY = (float)viewport[3] - (float)y;
glReadPixels( x, int(winY), 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ );
gluUnProject( winX, winY, winZ, modelview, projection, viewport, &posX, &posY, &posZ);
return CVector3(posX, posY, posZ);
}

Hope this helps...