On 11/02/2023 18:48, Bald Eagle wrote:
> 
> screen.inc doesn't do anything except organize things into a well-defined box
> that exactly matches the view frustum of the camera.  The box is squished very
> thin, and positioned so that it fills the entire camera from edge to edge.
> 
> So no, it still doesn't "convert 3D coordinates to 2D coordinates".   What it
> does allow you to do is use <u, v> values of the image plane to place 3D objects
> at that location.  That's why those values are in the -0.5 to 0.5 range But all
> that does is define the image plane as a constant z-value (or some distance
> along whatever vector the view the direction is defined as).
> 


Sorry Bald, but I don't agree with you.

Look at the image in this message. Render at 800x600.
The yellow point is at <4,5,3>. They are indeed 3d coordinates.
Now the black text says that this same point has the coordinates x=428
(from left to right) and y=163 (top to bottom).
This is a 2d coordinate in the image.

Of corse, if the image is render  at 1024 by 768, the 2D coordinate is
548 and 208.


So, the macro Get_Screen_XY(Loc) in screen.inc convert 3d to 2d coordinates.

After that, it may not meet your need, I agree ;)




-- 
Kurtz le pirate
Compagnie de la Banquise

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