1/16/2023 0 Comments Ray box intersection![]() ![]() Theoretically works in an arbitrary number of dimensions Check it out on GitHub. This works if t2 is NaN, but doesn't handle t1. Determine the point of intersection between a ray and axis-aligned bounding box (AABB). We'd like to keep tmin and tmax unchanged if either t1 or t2 is NaN, so swapping the arguments to keep tmin/ tmax on the right seems like a good idea: - tmin = max(tmin, min(t1, t2)) GeometryĪn axis-aligned bounding box □ \square □ can be specified by the coordinates of two of its corners: □ min = ( x min y min z min ) \square_ = y. To save you the trouble of (re-)reading the last two posts, I'll start with a quick recap.įeel free to skip to the next section if you're already familiar with it. Last time I wrote about ray/box intersections, we left off with a simple and fast implementation of the slab method that handles all the corner cases. If not, test the next nearest intersection, and so on. To determine if that point is within the face (remember, the plane is infinite) you check if the point is inside all the other planes. On -14 I substantially revised this post, improving the implementation and adding a much more thorough performance analysis. To ray-trace this you determine the ray/plane intersections and choose the nearest one. Of course, degenerate doesn't mean impossible or even unlikely, so it would be nice to include the boundary. For the oblique line which equation is yx-1 we have m1 and b-1. The equation of a line can be written as ymx b. This might not be too big a deal, since rays that exactly touch the boundary of the box are a somewhat degenerate case. Ray-Box Intersection Figure 1: equation of a line. However, it supersedes the previous two, and should be self contained, so don't feel like you have to read the others unless you're interested in the historical context. That means rays which just touch a corner, edge, or face of the bounding box will be considered non-intersecting. This post is the third in a series of posts I've written about ray/bounding box intersection tests.
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