how can i convert my window position(mouse pos from mouse event) to my “world” position.
i googled an example using gluUnProject but it doesn’t return “good” values.
so what i need is to convert my current mouse pos to scene pos so i can cast a ray to pick object under my mouse.
any pointer’s to tutorial or example code would be helpfull.
Saying it doesn’t return good values doesn’t help much - wrong values how? You should be able to project two points and create a ray from them.
Otherwise, try using gluProject as a debugging aid to see what values you should be providing to gluUnProject…
doesn’t return “good” value mean’s that it alway’s return’s
x:0.0
y:0.0
z:0.0
sorry for not mention it.
That sounds mighty odd - are you sure your matricies are setup correctly? And that you’re retreiving your values correctly?
Hows about posting the code? My telepathy isn’t working today 
;D
float camx = posV.x;
float camy = posV.y;
float camz = posV.z;
int viewport[] = new int[4];
double modelMatrix[] = new double[16];
double projMatrix[]=new double[16];
double rRay[]=new double[3];
gl.glGetIntegerv(GL.GL_VIEWPORT, viewport);
gl.glGetDoublev(GL.GL_MODELVIEW_MATRIX, modelMatrix);
gl.glGetDoublev(GL.GL_PROJECTION_MATRIX, projMatrix);
glu.gluUnProject(
x, //mouse x
y, //mouse y
1.0, //z but which is the correct value????
modelMatrix,
projMatrix,
viewport,
rRay,
rRay,
rRay);
One thing which is wrong for sure is triple rRay at the end. You should pass 3 single-element arrays instead of passing single 3-element array three times.
Aye, try changing it to this:
glu.gluUnProject(
x, //mouse x
y, //mouse y
1.0, //z but which is the correct value????
modelMatrix,
projMatrix,
viewport,
rRay,
rRay+4,
rRay+8);
The z value is going to be app dependant, but you can typically chose two arbitrary values such as 1 and 10 and use the two points to construct your ray.
Edit: Oops, Jogl code, not lwjgl :-[ So you’ll need to make fresh arrays for the extras, not use a pointer offset.
so the last line becomes:
glu.gluUnProject(
x, //mouse x
y, //mouse y
1.0, //z but which is the correct value????
modelMatrix,
projMatrix,
viewport,
rRay_x,
rRay_y,
rRay_z);
right?
with rRay_x,y,z being array of size 3.
why’s that? i’m used to have command like this©:
gluUnProject ((GLfloat)x,(GLfloat)y, 1.0, modelMatrix,
projMatrix, viewport, &rRay[0], rRay[1], &rRay[2]);
so this is becose of pointers?
anything else in jogl has this kind of tricks?
but it still return’s values 0.0,0.0,0.0
and gluUnProject return’s GL_FALSE
so that’s the reason for returning zero’s.
but why it can’t project?
i’m calling this method every time mouse has been clicked
on canvas
and when i check error’s with glError after gluUnProject
it give’s invalid operation.
and when i put DebugGL to canvas it complain’s about every gl.glEnd();
and when i remove them it work’s but when i click on canvas
so that it call’s to method that contains gluUnproject
it give’s me out of memory exception.
this is bit odd why it give’s error from glEnd()?
now i know the problem,it isn’t gluUnProject that is failing,
it’s glGetDoublev and glGetIntegerv.
those return’s full of zero’s array
for GL.GL_MODELVIEW_MATRIX,GL.GL_PROJECTION_MATRIX and GL.GL_VIEWPORT.
now i need to know why those fail’s and how to fix this. 
Post your code for them then
some init stuff
double model_view[] = new double[16];;
double projection[] = new double[16];
int viewport[] = new int[4];
and the code to get the values
gl.glGetDoublev(GL.GL_MODELVIEW_MATRIX, model_view);
int glError = gl.glGetError();
//this gives iinvalid operation string when using gluErrorString
gl.glGetDoublev(GL.GL_PROJECTION_MATRIX, projection);
glError = gl.glGetError();
//this gives invalid operation string when using gluErrorString
gl.glGetIntegerv(GL.GL_VIEWPORT, viewport);
glError = gl.glGetError();
I tried the glGet calls exactly as you had them written, and they worked fine - then I noticed you said this. Odds are you’re calling glGet from a different thread that the GL context is currently active in. There is a way to change this (i noticed it in the Animator source) but you’ll probably have nasty race conditions if you start tinkering with that.
My advice would be to set a flag to indicate that your GL thread should project the point, and possibly do the work there, then you avoid most of these issues.
thanks,that was the problem.