## FYI: An artifact in GluPerspective()

### FYI: An artifact in GluPerspective()

FYI, on an Nvidia FX 5200 board, if you set the near clipping plane
distance in GluPerspective() to 0.0, your rendering will produce an
assortment of noisy artifacts when it attempts to do depth buffering.
The Reference Manual says that clipping plane distances are positive,
and, apparently, they're not kidding.

Matt Feinstein

--
The Law of Polarity: The probability of wiring a battery with
the correct polarity is (1/2)^N, where N is the number of times
you try to connect it.

### FYI: An artifact in GluPerspective()

> FYI, on an Nvidia FX 5200 board, if you set the near clipping plane
> distance in GluPerspective() to 0.0, your rendering will produce an
> assortment of noisy artifacts when it attempts to do depth buffering.

It will happen on any board, or any OpenGL implementation.

Quote:> The Reference Manual says that clipping plane distances are positive,
> and, apparently, they're not kidding.

Why should they be kidding?

It causes a divide by zero in the maths.

--
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### FYI: An artifact in GluPerspective()

>> FYI, on an Nvidia FX 5200 board, if you set the near clipping plane
>> distance in GluPerspective() to 0.0, your rendering will produce an
>> assortment of noisy artifacts when it attempts to do depth buffering.

>It will happen on any board, or any OpenGL implementation.

>> The Reference Manual says that clipping plane distances are positive,
>> and, apparently, they're not kidding.

>Why should they be kidding?

>It causes a divide by zero in the maths.

Obvious in retrospect, as ever.

Matt Feinstein

--
The Law of Polarity: The probability of wiring a battery with
the correct polarity is (1/2)^N, where N is the number of times
you try to connect it.

I have  the following definition.
gluPerspective(fov,
width/height,
near,
far);

When a user clicks on any point on the screen (viewport) I would like to
determine the value of that point in the world coordinate (let's say at
z = 0).

I don't want to select any object, I just want to know the coordinate.