vm6502q / OpenRelativity

An open source framework to add the effects of traveling at relativistic speeds to visualizations or games
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Kerr metric #51

Closed WrathfulSpatula closed 3 years ago

WrathfulSpatula commented 3 years ago

Our guiding principle is that Kerr metric is diffeomorphically related to Schwarzschild, as a locally rotating Schwarzschild metric.

In "entity-component-system" ("ECS") physics simulation, it's trivial to approximate this, as like a ConformalMap layer between a Schwarzschild tangent space and the consumer of Kerr geometry methods.

As such, for GetRindlerAcceleration(), we just compose Kerr->Schwarzschild->Minkowski. For ComoveOptical(), we should fully integrate a path over time through both Kerr and Schwarzschild geometry at once, but the accuracy of an endpoint-based finite difference simulation, in either order of ConformalMap co-motion application, limits to 0 error for an infinitesimal finite difference time step.

This is surprisingly simple in "ECS" paradigm, as a step toward completing issue #50.