/*

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

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The RosyWriter OpenCV based effect renderer

 */

#import "RosyWriterOpenCVRenderer.h"

// To build OpenCV into the project:

//  - Download opencv2.framework for iOS

//  - Insert framework into project's Frameworks group

//  - Make sure framework is included under the target's Build Phases -> Link Binary With Libraries.

#import <opencv2/opencv.hpp>

@implementation RosyWriterOpenCVRenderer

#pragma mark RosyWriterRenderer

- (BOOL)operatesInPlace

{

    return YES;

}

- (FourCharCode)inputPixelFormat

{

    return kCVPixelFormatType_32BGRA;

}

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

{

    // nothing to do, we are stateless

}

- (void)reset

{

    // nothing to do, we are stateless

}

- (CVPixelBufferRef)copyRenderedPixelBuffer:(CVPixelBufferRef)pixelBuffer

{

    CVPixelBufferLockBaseAddress( pixelBuffer, 0 );

    unsigned char *base = (unsigned char *)CVPixelBufferGetBaseAddress( pixelBuffer );

    size_t width = CVPixelBufferGetWidth( pixelBuffer );

    size_t height = CVPixelBufferGetHeight( pixelBuffer );

    size_t stride = CVPixelBufferGetBytesPerRow( pixelBuffer );

    size_t extendedWidth = stride / sizeof( uint32_t ); // each pixel is 4 bytes/32 bits

    // Since the OpenCV Mat is wrapping the CVPixelBuffer's pixel data, we must do all of our modifications while its base address is locked.

    // If we want to operate on the buffer later, we'll have to do an expensive deep copy of the pixel data, using memcpy or Mat::clone().

    // Use extendedWidth instead of width to account for possible row extensions (sometimes used for memory alignment).

    // We only need to work on columms from [0, width - 1] regardless.

    cv::Mat bgraImage = cv::Mat( (int)height, (int)extendedWidth, CV_8UC4, base );

    for ( uint32_t y = 0; y < height; y++ )

    {

        for ( uint32_t x = 0; x < width; x++ )

        {

            bgraImage.at<cv::Vec<uint8_t,4> >(y,x)[1] = 0;

        }

    }

    CVPixelBufferUnlockBaseAddress( pixelBuffer, 0 );

    return (CVPixelBufferRef)CFRetain( pixelBuffer );

}

@end