color problem

hello I can not understand, if the vertex was not occupied, the other vertex on ray direction was occupied, how to know the vertex can be see?
in your video you have draw the line from carmer to the vertex but in your code the length is from bounds to the depth

Review the referenced video and compare its camera-to-vertex visibility explanation with the code’s bounds-to-depth length calculation. Reproduce the reported occupied and unoccupied vertex case, then document or correct the behavior once the expected visible vertex result is established.

Written by the indexing model from the issue text.