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## MpvRenderContext

# Struct MpvRenderContext

Source

    pub struct MpvRenderContext {
        ctx: *mut mpv_render_context,
        gl: Gl,
        target: Option<Target>,
    }

Expand description

mpv’s render context plus the framebuffer it draws into.

## §Lifetime (DR-232)

The render context must not outlive the GL context it was created against. `Drop` unregisters mpv’s update callback before freeing the context, so a callback cannot land on a freed pointer, and frees the GL objects while the caller still has the context current. The caller is responsible for making the GL context current around both creation and drop — see `video_surface`.

This is DR-184 on Android restated: a surface outliving its player. The spike had no defence at all and saw one unexplained SIGSEGV in a decoder thread.

## Fields§

§ `ctx: *mut mpv_render_context` § `gl: Gl` § `target: Option<Target>`

## Implementations§

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### impl MpvRenderContext

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#### pub unsafe fn new(mpv: *mut mpv_handle) -> Option<Self>

Create a render context over an existing mpv handle.

The GL context must already be current on this thread.

TRACES: UR-080 | DR-231, IR-033

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#### pub unsafe fn set_update_callback( &mut self, callback: mpv_render_update_fn, ctx: *mut c_void, )

Ask to be told when a new frame is ready.

Paired with `report_swap`: without both, mpv has nothing to time against. The symptom is misleading — playback looks fine in a window and judders at fullscreen, which reads as a compositing or GPU limit and is neither (DR-233).

TRACES: UR-080 | DR-233

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#### pub unsafe fn has_frame(&self) -> bool

Whether mpv has a new frame waiting.

Asked of mpv directly rather than inferred from its update callback, and that distinction is the whole of frame pacing here:

- Waiting only on the callback deadlocks — mpv will not progress until the client renders, so if the client will not render until mpv says so, neither moves. That presents as a file that loads, shows one frame, and then sits silent.
- Rendering on every frame-clock tick regardless is the opposite error: `report_swap` then claims a presentation far more often than real frames exist, mpv has nothing coherent to time against, and playback judders badly.

Polling is neither. It runs on the main thread, costs a single atomic read inside mpv, and answers the only question that matters.

TRACES: UR-080 | DR-233

Source

#### pub unsafe fn render(&mut self, width: i32, height: i32) -> Option<u32>

Render the current frame at `width` x `height`, returning the texture id holding it. The GL context must be current.

TRACES: UR-080 | DR-231

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#### pub unsafe fn report_swap(&self)

Tell mpv the frame reached the screen. See [`set_update_callback`].

TRACES: UR-080 | DR-233

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#### unsafe fn ensure_target(&mut self, width: i32, height: i32) -> Option<()>

Create or resize the framebuffer. Reused across frames — reallocating per frame would churn GPU memory at the display rate.

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#### unsafe fn drop_target(&mut self)

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#### pub unsafe fn destroy(self)

Free everything, with the GL context current.

Explicit rather than left to `Drop` because the ordering matters and the caller is the only one that can guarantee the GL context is current. See DR-232.

## Trait Implementations§

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### impl Drop for MpvRenderContext

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#### fn drop(&mut self)

Executes the destructor for this type. Read more
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#### fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (`pin_ergonomics`)
Execute the destructor for this type, but different to `Drop::drop`, it requires `self` to be pinned. Read more
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### impl Send for MpvRenderContext

## Auto Trait Implementations§

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### impl Freeze for MpvRenderContext

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### impl RefUnwindSafe for MpvRenderContext

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### impl !Sync for MpvRenderContext

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### impl Unpin for MpvRenderContext

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### impl UnsafeUnpin for MpvRenderContext

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### impl UnwindSafe for MpvRenderContext

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