CS 307 Homework: Textured Barn¶

The emphasis in this assignment is working with textures. It's not primarily about geometry. You may decide to modify the texture coordinates, which live in the geometry, or you might not. (I did not.) Also, it uses material and lighting, but keep this part simple. It's also not about cameras, so feel free to use TW.cameraSetup().

Here's the goal, a barn with siding and roofing, which I'm calling a textured barn.

solution

Note the modes that the GUI makes available:

• showTextures helps to explain how the default texture coordinates are assigned.
• showLighting puts white Phong material on the barn, so you can see the lighting effects. Definitely pay attention to this.
• showResult is, of course, the desired product

These modes will help you understand where the faces are and how the textures are arranged (at least initially), though you have control of the texture coordinates. You only need to implement the last two modes.

Getting Started¶

Create the following geometry, using a function that I defined for you:

// This has 9 faces. Here's the documentation in tw-fa.25; feel free
// to look at the code as well.

/* The resulting geometry has these sides/material groups:

     0 front quad
     1 east or +x quad
     2 west -x quad
     3 east roof quad
     4 west roof quad
     5 bottom quad
     6 back quad
     7 front upper triangle
     8 back upper triangle
     */

    const barnGeometry = TW.barnGeometryWithMaterialGroups(30, 40, 50);

    // replace this with a mesh that has material with lighting and textures.
    const barnMesh = TW.createMesh(barnGeometry);

You will need to use this TW.barnGeometryWithMaterialGroups function that I've defined for you.

Most of your work will be setting up the material and lighting and then applying the textures, which is all in the material part of the mesh.

If you want to fiddle with the texture coordinates, you are welcome to do so. To do that, you can copy the definition of TW.barnGeometryWithMaterialGroups into your main.js and then modify the copy. But that is not required.

Stuff to Know¶

Older versions of Threejs said that texture repetition works best if the dimensions of the texture image are powers of two. You don't get an error if the dimensions are not powers of two (although you'll see a warning in the JS console), but the effect is as if you used "clamp." It's easy enough to use Pixlr or Photoshop (or even just Preview on a Mac) to resize an image to have power-of-two dimensions. However, that seems no longer to be the case.

What You Need to Do¶

Write your own program that mimicks this object:

• Use material and lighting throughout; no THREE.MeshBasicColor, though of course you can use them when debugging.
• You'll need an ambient light and a directional light.
• Make your best guess at the material colors.
• Texture-map some textures on the walls and roof of the barn. Use wood or brick or some kind of reasonable "wall-like" material for the sides, and similarly for the roof. You don't need to use textures exactly like the ones used in the model solution; make it look nice.
• Note that the top of the front and back aren't triangles that are part of quads. You'll need to figure out the best way to deal with this.
• There's a GUI with a menu. You need not implement the UV option, but implement some way to turn off the material so that we can see the lighting. This will help you in your debugging, too, so it's not a waste of time.
• You must use repetition in your texture-mapping: find an image that looks nice as part of the barn's sides or roof, and then "tile" it across the surface. That's much of what texture-mapping is about.
• Feel free to ask questions!

Implement this as texbarn/ in your cs307-assignments folder.

Please read the standard instructions for all assignments