align/merge vector and vector_array types

[jopadan]

Pull Request Type

• GitHub Workflow changes
• Documentation or Wiki changes
• Build and Dependency changes
• Runtime changes
  • Render changes
  • Audio changes
  • Input changes
  • Network changes
  • Other changes
  • Math changes

Description

The game Freespace 2 uses a more advanced Volition vecmat library than Descent 3.

• introduce default scalar and aligned_vector type.
• merge vector_array types with vector types using union.
• add neutral/identity to vector/matrix types.

Checklist

• I have tested my changes locally and verified that they work as intended.
• I have documented any new or modified functionality.
• I have reviewed the changes to ensure they do not introduce any unnecessary complexity or duplicate code.
• I understand that by submitting this pull request, I am agreeing to license my contributions under the project's license.

[Lgt2x]

Hello, thanks for opening this PR. However I feel like some context is missing: could you please be more explicit about 1) the purpose of this change 2) the exact problem you are trying to solve. Did you find memory alignment issues in existing code?

[Lgt2x]

The macos CI found new warnings caused by these changes : https://github.com/DescentDevelopers/Descent3/actions/runs/13578120176/job/38006605278?pr=674#step:14:179

Mac and Windows also have build failures:

Error: /Users/runner/work/Descent3/Descent3/lib/vecmat_external.h:61:41: error: unknown type name 'ssize_t'; did you mean 'size_t'?
constexpr static inline const angvec id(ssize_t i = -1)
                                        ^~~~~~~
                                        size_t

[jopadan]

@Lgt2x: ssize_t and type initializer problems now fixed with:

typedef std::make_signed<size_t>::type ssize_t;
return matrix{(T)1,(T)2,(T)3};

[Lgt2x]

The last comments from me are nitpicking from me, this is good enough. It plays fine on Linux. Thanks again @jopadan , this vector interface is much better than what we had!