Texture mapping overview

General pipeline: Shoot a ray (pixel) -> Determine a point on surface -> Texture/color of that surface point -> Light source (or in case of ray tracing, bounce off the surface, and figure out reflection)

Typical problems with texture map: 1) Seams between beginning and end of texture (deform -> realign), 2) Discontinuity at surface intersection (smooth out the geometry)

UV (surface coordinate) vs. ST (texture coordinate): UV are the two directions on the surface determined by the curves that form the patch. ST manipulates the texture map itself in relation to the surface; in case the surface geometry changes, ST can be used to warp the texture to undo the effect of surface warping.

A video sequence showing examples of different maps: projection map, solid(3D) map, transparency map, specular map, etc.

Different ways of placing 2D texture on 3D object: 1) Create 2D texture -> wrap it around 3D object -> unwrap -> adjust by painting in 2D -> wrap it back on surface -> ... 2) 3D painting (directly on the object surface)

Bump map vs. displacement map: Bump map simulates bumpy surface by perturbing the surface normal (thus perturbing reflection angles), while displacement map actually perturbs surface geometry itself (therefore takes longer to compute)

Reflection map vs. ray tracing: Reflection map simulates ray tracing with less computation; it only computes one global map of the environment onto a surrounding surface (spherical, cylindrical, etc.), then applies it as a texture map on each object in the scene, whereas in ray tracing individual rays are sent through the scene for every pixel of the image.

Specular vs. diffuse reflection: In specular reflection, rays are reflected at a more or less uniform angle, creating clear reflection and highlights. In diffuse reflection, lights are bounced off at random angles, and unreflective surface is created.

Ambient light: not a single light source; adds a general level of brightness to the scene.