XPLM Processing API

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This API allows you to get regular callbacks during the flight loop, the part of X-Plane where the plane's position calculates the physics of flight, etc. Use these APIs to accomplish periodic tasks like logging data and performing I/O.

You can receive a callback either just before or just after the per-frame physics calculations happen - you can use post-flightmodel callbacks to "patch" the flight model after it has run.

If the user has set the number of flight model iterations per frame greater than one your plugin will not see this; these integrations run on the sub-section of the flight model where iterations improve responsiveness (e.g. physical integration, not simple systems tracking) and are thus opaque to plugins.

Flight loop scheduling, when scheduled by time, is scheduled by a "first callback after the deadline" schedule, e.g. your callbacks will always be slightly late to ensure that we don't run faster than your deadline.

WARNING: Do NOT use the post-flightmodel callback for initialization, resource creation, etc. The only recommended use of post-FM callbacks is to "patch" the computed values of the flightmodel using dataref read-writes, and to compute custom system values by reading the flightmodel. APIs that create resources or initialize the sim may issue warnings, crash rhe sim, or have unexpected results.

WARNING: Do NOT use these callbacks to draw! You cannot draw during flight loop callbacks. Use the drawing callbacks (see XPLMDisplay for more info) for graphics or the XPLMInstance functions for aircraft or models. (One exception: you can use a post-flight loop callback to update your own off-screen FBOs.)