Struct cp_frame 

#[repr(C)]
pub struct cp_frame { /* private fields */ }

Available on crate feature frame only.

Apple’s documentation

Implementations

impl cp_frame

pub unsafe fn frame_index(frame: cp_frame_t) -> cp_layer_frame_index_t

Available on crate feature cp_types only.

Returns the sequential index number of the specified frame.

• Parameters:
• frame: The frame to query.
• Returns: The sequential index of the frame, which is always a positive integer.

The layer assigns a unique index number to each frame, starting at the first frame and incrementing the index by 1 for each new frame.

pub unsafe fn predict_timing(frame: cp_frame_t) -> cp_frame_timing_t

Available on crate feature frame_timing only.

Computes and returns the predicted timing information for the specified frame.

• Parameters:
• frame: The frame you’re preparing to draw.
• Returns: The predicted timing information for the specified frame, or NULL if the layer is in the cp_layer_renderer/cp_layer_renderer_state_paused or cp_layer_renderer/cp_layer_renderer_state_invalidated state.

Use the returned timing information in any functions that return frame-related deadlines. For example, pass the timing information to the cp_frame_timing_get_optimal_input_time function to determine when to start encoding the frame. This function updates the frame-specific timing information using the latest data from the compositor before it returns it.

Don’t call this function after you call cp_frame_query_drawable for the specified frame. If you need the timing information after you retrieve the frame’s cp_drawable_t type, save the return value of this function, or call cp_drawable_get_frame_timing to get the information from the drawable instead.

pub unsafe fn query_drawable(frame: cp_frame_t) -> cp_drawable_t

Available on crate feature drawable only.

Returns the drawable type you use to retrieve the textures and drawing environment for the frame.

• Parameters:
• frame: The frame to query.
• Returns: The drawable type, or NULL if the layer is in the cp_layer_renderer/cp_layer_renderer_state_paused or cp_layer_renderer/cp_layer_renderer_state_invalidated state.

Call this function when you’re ready to encode the drawing commands for the frame. The cp_drawable_t type contains the textures and other information you need to set up your render descriptor in Metal.

Note: This function isn’t safe to be called concurrently. Always ensure a single thread call this function at a time.

pub unsafe fn start_update(frame: cp_frame_t)

Notifies the compositor that you started updating the app-specific content you need to render the frame.

• Parameters:
• frame: The frame you are ready to prepare.

This function helps you optimize your app’s rendering efficiency. Before you render a frame, you might need to respond to interactions and update your app’s data structures before you can render items in your scene. Call this function immediately before you start that work, and call the cp_frame_end_update function as soon as you finish. The compositor uses the time difference to improve its predictions for when to start the frame encoding process.

Move as much work as possible into the update phase to minimize encoding time. Don’t do any work that relies on the current pose information during the update phase. Instead, make any pose-related changes during the encoding phase.

pub unsafe fn end_update(frame: cp_frame_t)

Notifies the compositor that you finished updating the app-specific content you need to render the frame.

• Parameters:
• frame: The frame you finished preparing.

This function helps you optimize your app’s rendering efficiency. Before you render a frame, you might need to respond to interactions and update your app’s data structures before you can render items in your scene. Call the cp_frame_start_update function immediately before you start that work, and call this function as soon as you finish. Compositor uses the frame update time to improve its predictions for when to start the frame encoding process.

Move as much work as possible into the update phase to minimize encoding time. Don’t do any work that relies on the current pose information during the update phase. Instead, make any pose-related changes during the encoding phase.

pub unsafe fn start_submission(frame: cp_frame_t)

Notifies the compositor that you’re ready to generate the GPU commands to render the specified frame.

• Parameters:
• frame: The frame you’re ready to encode and send to the GPU.

This function helps you optimize your app’s rendering efficiency. Call this function function before you start any of the GPU work that depends on the input data. Call the cp_frame_end_submission function after you finish your drawing commands and are ready to commit the frame to the GPU. Compositor uses the time difference to improve its predictions for when to start the frame submission process. Those predictions help you schedule the encoding process at a more optimal time for the system.

pub unsafe fn end_submission(frame: cp_frame_t)

Notifies the compositor that you finished generating the GPU commands to render the specified frame.

• Parameters:
• frame: The frame you’re ready to submit to the GPU.

This function helps you optimize your app’s rendering efficiency. Call the cp_frame_start_submission function before you start any of the GPU work that depends on the input data. Call this function after you finish your drawing commands and are ready to commit the frame to the GPU. Compositor uses the time difference to improve its predictions for when to start the frame submission process. Those predictions help you schedule the encoding process at a more optimal time for the system.

Trait Implementations

impl Debug for cp_frame

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl RefEncode for cp_frame

const ENCODING_REF: Encoding

The Objective-C type-encoding for a reference of this type.