\( \newcommand{\vecIII}[3]{\left[\begin{array}{c} #1\\\\#2\\\\#3 \end{array}\right]} \newcommand{\vecIV}[4]{\left[\begin{array}{c} #1\\\\#2\\\\#3\\\\#4 \end{array}\right]} \newcommand{\Choose}[2]{ { { #1 }\choose{ #2 } } } \newcommand{\vecII}[2]{\left[\begin{array}{c} #1\\\\#2 \end{array}\right]} \newcommand{\vecIII}[3]{\left[\begin{array}{c} #1\\\\#2\\\\#3 \end{array}\right]} \newcommand{\vecIV}[4]{\left[\begin{array}{c} #1\\\\#2\\\\#3\\\\#4 \end{array}\right]} \newcommand{\matIIxII}[4]{\left[ \begin{array}{cc} #1 & #2 \\\\ #3 & #4 \end{array}\right]} \newcommand{\matIIIxIII}[9]{\left[ \begin{array}{ccc} #1 & #2 & #3 \\\\ #4 & #5 & #6 \\\\ #7 & #8 & #9 \end{array}\right]} \)

Quiz

  1. How do we know if the texels will match well with the pixels? Will just have to use the magFilter/minFilter  just incase?

    Yes. One issue is that, say with the cone, you know that the texels will get crowded at the point, so you'll have to use minFilter. Also, the match of texels to pixels will depend on things you might not know during coding, such as the angle of the plane with the eye.

    Fortunately, the Threejs defaults are reasonable. But if you decide that things don't look right, you can adjust them.

  2. Some of the filters seem very similar (i.e. THREE.LinearMipMapNearestFilter and THREE.NearestFilter). Why/ how is the disctinction between these filters important?

    Yes, they do seem similar, and in many cases, it's hard to see much difference between them. (I've tried.)

    With mipmaps, you can create your own custom mipmaps and substitute them.

    In practice, I doubt this is worth a lot of effort. I think there would be more examples on the Threejs website if there were good cases where it mattered a lot.

  3. How can we best address the distortion at poles, when mapping onto a sphere? Is there a way to do so without editing the texture independently?

    Great question! One to which I don't really have a good answer, though I've always wanted to research it more.

    I think you'd have to either edit the texture coordinates, so that the texture at the polar areas is spread over a more-accurate amount of surface area.

    Alternatively, find/make a texture such that the areas near the top and bottom are squished a bit, so that when they are spread over the poles, they look better.

    Here's the source code for sphere geometry

    See the next question.

  4. What do you recommend we look for when we are looking for images to use in texture mapping? Is there a best format or resolution? Are there particular kind of images that look better on spheres?

    Let's look briefly at list of map projections and cylindrical equal-area projection

    That's why I referenced the cartographer's conundrum. I've always wanted to understand this better, but it does kinda veer outside of CS 307 proper.

  5. not so far, might ask some during class!

    Please do!