External driven clock

[jonyMarino]

Overview

This pull request introduces a new engine-driven simulation clock mode to Project AirSim, enabling the simulation to be advanced by Unreal's loop. This mode is designed for deterministic, fixed-step simulation where the host is responsible for providing elapsed time and triggering simulation ticks. The changes include the implementation of the EngineDriveClock class, updates to scene and clock management, Unreal integration, and comprehensive documentation updates.

Besides that, a placeholder external-clock was added for future use. The idea is to implement a capability to control the clock of the simulation from an outside source/orchestrator.

Simulation Clock Enhancements:

• Added a new EngineDrivenClock class, which allows Unreal's engine drive simulation time by supplying elapsed time and triggering steps in fixed increments (step-ns). This class provides methods for accumulating time, checking for pending steps, and stepping the simulation deterministically. [1] [2]
• Updated ClockType and related configuration to support the new engine-driven type, including schema, constants, and clock selection logic. [1] [2] [3] [4]

Scene and Simulation Loop Integration:

• Modified the scene tick logic to bypass the internal scheduler when engine-driven clock is selected, allowing the host to control simulation advancement via the new ExternalTick() method. [1] [2] [3] F97d1f83L97R1078, [4]

Unreal Engine Integration:

• Updated Unreal integration to detect and use the EngineDrivenClock, synchronizing Unreal's tick timing with the simulation step size and safely handling clock type detection without RTTI.

Documentation Updates:

• Expanded documentation to describe the new engine-driven clock, its configuration, use cases, and integration patterns. Updated API and configuration references to include the new clock type. [1] [2] [3] [4] [5]

Code Quality and Comments:

• Added clarifying comments throughout the clock and scheduler code to improve maintainability and developer understanding. [1] [2] [3] [4] [5] [6] [7]

These changes make Project AirSim more flexible and embeddable, supporting advanced integration scenarios with external runtimes and engines.

[github-actions]

✅ ProjectAirSim Self-Hosted CI

• Status: success
• Pytest results: tests=161, failures=0, errors=0, skipped=0
• Artifacts: test-results

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[LucasJSch]

LGTM