Fix Occlusion Culling not working for an orthogonal camera.

[Rudolph-B]

Fixes #98561

This issue was caused by two problems:

• The directions generated for the raycasts used for the depth map to determine occlusion pointed in the wrong direction.
• The minimum depth value calculated using an object’s AABB and used by _is_occluded() to determine occlusion was negative (a bug I introduced in Fix to occlusion culling where all math is based on Euclidean distance. #98257 🙈).

This PR fixes both.

MRP: mrp.zip

[clayjohn]

Makes sense to me.

[Calinou]

Tested locally, it works as expected, but only at high zoom levels.

Culling doesn't work anymore once you unzoom the orthogonal camera in the editor:

simplescreenrecorder-2024-10-28_16.58.18.mp4

Moving the cube further away from the wall doesn't resolve this.

[Rudolph-B]

I see. It seems the occlusion buffer disorientates itself somehow when zoomed out.
Screencast from 2024-10-28 18-59-25.webm.
Not really sure how this happens yet. I'll fix it.

[Repiteo]

Thanks!