Pure FOV / focal-length conversion helpers used by the camera section of the rendering-controls panel.
Extracted from camera-setup.ts so the optical math is unit-testable without instantiating a SceneManager or a GUI.
Pure FOV / focal-length conversion helpers used by the camera section of the rendering-controls panel.
Extracted from camera-setup.ts so the optical math is unit-testable without instantiating a SceneManager or a GUI.