added length, length_sq, normalize for vec4.

[mcdubhghlas]

AR needed this, still needs more for vec4.

Summary by CodeRabbit

• New Features
  • Added four utility functions for 4D vector mathematics: squared magnitude calculation, magnitude calculation, safe normalization with zero-length validation, and optimized fast normalization for performance-critical code paths. All functions include compiler optimization hints for efficient, low-overhead vector operations.

[coderabbitai]

📝 Walkthrough

Walkthrough

Four new exported inline utility functions added to draco::math::Vector4 for computing squared magnitude, magnitude, normalization (with zero-check), and fast normalization (without zero-check). All functions are marked [[nodiscard]], FORCEINLINE, and noexcept.

Changes

Cohort / File(s)	Summary
Vector4 Utility Functions engine/native/core/math/vector4.cppm	Added four inline utility functions: length_sq(), length(), normalize(), and normalize_fast() for Vector4 magnitude and normalization operations with [[nodiscard]], FORCEINLINE, and noexcept annotations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 Four functions hop into the code,
Vector math takes lighter load!
Length, normalize, fast and clean,
Simplest utilities you've ever seen! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main changes: it lists the three primary functions added (length, length_sq, normalize) and specifies they are for vec4.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

engine/native/core/math/vector4.cppm (1)

161-166: Consider epsilon threshold for near-zero vectors.

The exact len > 0.0f check prevents division by zero, but vectors with extremely small magnitudes (e.g., 1e-40) will still be normalized, potentially producing numerically unstable results due to floating-point precision loss.

If robustness against near-zero vectors is desired, consider using an epsilon:

constexpr float EPSILON = 1e-8f;
return (len > EPSILON) ? v / len : Vector4{0,0,0,0};

That said, the current implementation is valid and the behavior is well-documented by the comment. This can be addressed later if it causes issues in practice.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@engine/native/core/math/vector4.cppm` around lines 161 - 166, The normalize
function currently uses a strict len > 0.0f check which can produce unstable
results for very small magnitudes; update Vector4 normalize(const Vector4& v)
noexcept to compare length(v) against a small epsilon (e.g. constexpr float
EPSILON = 1e-8f) instead of 0.0f and return v / len only when len > EPSILON,
otherwise return Vector4{0,0,0,0}; use the existing length() helper and keep the
function signature and noexcept intact.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@engine/native/core/math/vector4.cppm`:
- Around line 161-166: The normalize function currently uses a strict len > 0.0f
check which can produce unstable results for very small magnitudes; update
Vector4 normalize(const Vector4& v) noexcept to compare length(v) against a
small epsilon (e.g. constexpr float EPSILON = 1e-8f) instead of 0.0f and return
v / len only when len > EPSILON, otherwise return Vector4{0,0,0,0}; use the
existing length() helper and keep the function signature and noexcept intact.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 405e18d2-d437-47c7-93af-a4cb11faa0f1

📥 Commits

Reviewing files that changed from the base of the PR and between 54bb414 and 1833dae.

📒 Files selected for processing (1)

• engine/native/core/math/vector4.cppm

[AR-DEV-1]

LGTM