Revert "Remove unimportant conditional in hit_plane_within_box"
Revert "Remove unimportant conditional in hit_plane_within_box"

This reverts commit 4bfa1b27241b58e5f3b48d57c45f621242702f03.

This caused vertical black stripes appear on screen under some conditions

shamazmazum/voxvision,shamazmazum/voxvision