bugfix(heightmap): Fix ray casting in BaseHeightMapRenderObjClass::Cast_Ray (2)

[xezon]

• Follow up for bugfix(heightmap): Reduce ray cast lengths and fix ray casting in BaseHeightMapRenderObjClass::Cast_Ray #2836

This change is follow up for #2836 and applies more fixing in the Cast_Ray function.

Before this change the ray cast was failing if the camera was positioned below the max terrain height. The logical consequence was that no unit could be ordered to move anywhere on close zoom.

With the fixed logic the initial terrain hit box is assembled in a way that the ray cast has a chance to hit it before moving forward with the narrowing search.

[greptile-apps]

Greptile Summary

This PR refines terrain ray casting for close camera views. The main changes are:

• Build terrain bounds from the map's minimum and maximum heights.
• Keep ray endpoints when a ray begins inside a terrain box.
• Update box collision contact points for inside-start rays.
• Avoid applying negative camera far clip distances.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
Core/GameEngineDevice/Source/W3DDevice/GameClient/BaseHeightMap.cpp	Updates terrain-bound clipping and iterative ray narrowing.
Core/GameEngineDevice/Source/W3DDevice/GameClient/W3DView.cpp	Skips camera clip-plane updates for negative far distances.
Core/Libraries/Source/WWVegas/WWMath/castres.h	Clarifies the meaning of inside-start collision results.
Core/Libraries/Source/WWVegas/WWMath/colmathline.cpp	Sets contact points for line-box collisions that start inside a box.

_{Reviews (5): Last reviewed commit: "Allow ray casts to start inside all boxe..." | Re-trigger Greptile}

[Caball009]

The logical consequence was that no unit could be ordered to move anywhere on close zoom.

I tested this and it appears to work correctly now. Haven't looked at the code yet.

[Caball009]

In my effort to understand how BaseHeightMapRenderObjClass::Cast_Ray works, I found myself doing a cleanup / refactor because the initial function setup is a mess. I don't have permission to push the results of that effort to your branch, so here's my own: https://github.com/Caball009/GeneralsGameCode/tree/xezon/fix-cast-ray Perhaps you'll find it useful to include in this PR.

[xezon]

More refactor is beyond the goal of this change so I will leave it as is in this pull.

[Caball009]

Fair enough. Perhaps I'll do a follow-up.

[Caball009]

Looks alright to me.

[xezon]

Looks alright to me.

I added another commit because I realized we can simplify it and get rid of the new math mumbo jumbo by allowing inside collisions for the first terrain box.

[Caball009]

I'll try to have a look at it in a bit.

Changes since review,

[Caball009]

I noticed that the cursor feedback changed between retail and this project for unit orders to spots outside the map. I suspect it's the result from previous ray cast changes. Should it be fixed? It looks purely visual. Notice how it changes with a slightly different camera angle.

Videos

Retail:

gen_zh_move_order_retail.mp4

This project (main branch and this branch):

gen_zh_move_order_tsh.mp4

[xezon]

I noticed that the cursor feedback changed between retail and this project for unit orders to spots outside the map. I suspect it's the result from previous ray cast changes. Should it be fixed? It looks purely visual. Notice how it changes with a slightly different camera angle.

I suspect it is also related to short far Z. I have not seen that on the maps I tested with. Can you share map?

[Caball009]

Can you share map?

https://github.com/TheSuperHackers/GeneralsGameCode/pull/ 2846#issuecomment-5006788343
https://github.com/user-attachments/files/30136967/1v1.nomoney.survival.zip

[Caball009]

Were you able to reproduce the issue?

[xezon]

Yes it is definitely caused by the far clip plane in W3DView::updateCameraClipPlanes. I currently do not know how to solve this. This map has no border and it is clicking on nothing (or water) in the blackness.

[xezon]

A potential workaround would be to extend the far clip plane during W3DInGameUI::drawMoveHints, but that seems like a hack.

[Caball009]

It's not a big deal as it's only visual feedback. I'm okay with ignoring it for now if you don't see a reasonable way to fix it.

[xezon]

Yes it would be nice to restore original look, but I do not know how to elegantly do that.

I think we need to compare visuals of Special Power planes at the edges of the map. If they also look strange, then we definitely need to do something.