Re: [ZE-dev] Some requests

[Filippos P. <css...@cs...>]

On Mon, 13 Oct 2003, James Turk wrote:

>
> >> - I also believe that it would be better to use GL_LINEAR for Image
> >> Stretching not GL_NEAREST. Maybe u could put an extra parameter in the
> >> function Resize/Stretch.
> >>
> >
>
> In SDLGL_Util.cpp, I changed the lines
> glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
> glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
>  to
> glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
> glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
> and noticed a visible difference.   I'm not an OpenGL expert, so why
> would anyone want to use GL_NEAREST?
>
>  From what I've seen I propose simply changing these lines and nothing
> else but if I am going to bother leaving GL_NEAREST, instead of forcing the
> change inside Resize/Stretch, would it not be best to simply have that
> as an option defined for each ZImage, that way a minimal number of calls
> to glTexParamteri would be required, and none would be required inside
> the rendering loop in most situations, which I'd consider a good thing.
>
> Feel free to share any thoughts on this, the finer points of OpenGL are
> certainly not my specialty.
>
>           -James


Well i am not an OpenGL guru either ;)
To be honest i havent fully understood what you wanna say here (see
English is not my native language). I can tell these (by what i have
understood):

Why not putting an extra parameter in the Stretch/Resize function (or in
the constructor of a ZImage) e.g named 'smooth' ? This way it is up to the
developer to decide if he needs smoothed image or not.
 Someone would say that GL_LINEAR produces blurred images, which is not
always a good case. On the other hand GL_NEAREST is faster than LINEAR.