/*

 Copyright (C) 2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 A generic protocol for renderer objects used by RosyWriterCapturePipeline

 */

#import <Foundation/Foundation.h>

#import <CoreMedia/CoreMedia.h>

#import <CoreVideo/CoreVideo.h>

@protocol RosyWriterRenderer <NSObject>

@required

/* Format/Processing Requirements */

@property(nonatomic, readonly) BOOL operatesInPlace; // When YES the input pixel buffer is written to by the renderer instead of writing the result to a new pixel buffer.

@property(nonatomic, readonly) FourCharCode inputPixelFormat; // One of 420f, 420v, or BGRA

/* Resource Lifecycle */

// Prepare and destroy expensive resources inside these callbacks.

// The outputRetainedBufferCountHint tells out of place renderers how many of their output buffers will be held onto by the downstream pipeline at one time.

// This can be used by the renderer to size and preallocate their pools.

- (void)prepareForInputWithFormatDescription:(CMFormatDescriptionRef)inputFormatDescription outputRetainedBufferCountHint:(size_t)outputRetainedBufferCountHint;

- (void)reset;

/* Rendering */

// Renderers which operate in place should return the input pixel buffer with a +1 retain count.

// Renderers which operate out of place should create a pixel buffer to return from a pool they own.

// When rendering to a pixel buffer with the GPU it is not necessary to block until rendering has completed before returning.

// It is sufficient to call glFlush() to ensure that the commands have been flushed to the GPU.

- (CVPixelBufferRef)copyRenderedPixelBuffer:(CVPixelBufferRef)pixelBuffer;

@optional

// This property must be implemented if operatesInPlace is NO and the output pixel buffers have a different format description than the input.

// If implemented a non-NULL value must be returned once the renderer has been prepared (can be NULL after being reset).

@property(nonatomic, readonly) CMFormatDescriptionRef __attribute__((NSObject)) outputFormatDescription;

@end