/*

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

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    The RosyWriter CoreImage CIFilter-based effect renderer

 */

#import "RosyWriterCIFilterRenderer.h"

@interface RosyWriterCIFilterRenderer ()

{

    CIContext *_ciContext;

    CIFilter *_rosyFilter;

    CGColorSpaceRef _rgbColorSpace;

    CVPixelBufferPoolRef _bufferPool;

    CFDictionaryRef _bufferPoolAuxAttributes;

    CMFormatDescriptionRef _outputFormatDescription;

}

@end

@implementation RosyWriterCIFilterRenderer

#pragma mark API

- (void)dealloc

{

    [self deleteBuffers];

}

#pragma mark RosyWriterRenderer

- (BOOL)operatesInPlace

{

    return NO;

}

- (FourCharCode)inputPixelFormat

{

    return kCVPixelFormatType_32BGRA;

}

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

{

    // The input and output dimensions are the same. This renderer doesn't do any scaling.

    CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions( inputFormatDescription );

    [self deleteBuffers];

    if ( ! [self initializeBuffersWithOutputDimensions:dimensions retainedBufferCountHint:outputRetainedBufferCountHint] ) {

        @throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Problem preparing renderer." userInfo:nil];

    }

    _rgbColorSpace = CGColorSpaceCreateDeviceRGB();

    EAGLContext *eaglContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];

    _ciContext = [CIContext contextWithEAGLContext:eaglContext options:@{ kCIContextWorkingColorSpace : [NSNull null] } ];

    _rosyFilter = [CIFilter filterWithName:@"CIColorMatrix"];

    CGFloat greenCoefficients[4] = { 0, 0, 0, 0 };

    [_rosyFilter setValue:[CIVector vectorWithValues:greenCoefficients count:4] forKey:@"inputGVector"];

}

- (void)reset

{

    [self deleteBuffers];

}

- (CVPixelBufferRef)copyRenderedPixelBuffer:(CVPixelBufferRef)pixelBuffer

{

    OSStatus err = noErr;

    CVPixelBufferRef renderedOutputPixelBuffer = NULL;

    CIImage *sourceImage = [[CIImage alloc] initWithCVPixelBuffer:pixelBuffer options:nil];

    [_rosyFilter setValue:sourceImage forKey:kCIInputImageKey];

    CIImage *filteredImage = [_rosyFilter valueForKey:kCIOutputImageKey];

    err = CVPixelBufferPoolCreatePixelBuffer( kCFAllocatorDefault, _bufferPool, &renderedOutputPixelBuffer );

    if ( err ) {

        NSLog( @"Cannot obtain a pixel buffer from the buffer pool (%d)", (int)err );

        goto bail;

    }

    // render the filtered image out to a pixel buffer (no locking needed as CIContext's render method will do that)

    [_ciContext render:filteredImage toCVPixelBuffer:renderedOutputPixelBuffer bounds:[filteredImage extent] colorSpace:_rgbColorSpace];

bail:

    return renderedOutputPixelBuffer;

}

- (CMFormatDescriptionRef)outputFormatDescription

{

    return _outputFormatDescription;

}

#pragma mark Internal

- (BOOL)initializeBuffersWithOutputDimensions:(CMVideoDimensions)outputDimensions retainedBufferCountHint:(size_t)clientRetainedBufferCountHint

{

    BOOL success = YES;

    size_t maxRetainedBufferCount = clientRetainedBufferCountHint;

    _bufferPool = createPixelBufferPool( outputDimensions.width, outputDimensions.height, kCVPixelFormatType_32BGRA, (int32_t)maxRetainedBufferCount );

    if ( ! _bufferPool ) {

        NSLog( @"Problem initializing a buffer pool." );

        success = NO;

        goto bail;

    }

    _bufferPoolAuxAttributes = createPixelBufferPoolAuxAttributes( (int32_t)maxRetainedBufferCount );

    preallocatePixelBuffersInPool( _bufferPool, _bufferPoolAuxAttributes );

    CMFormatDescriptionRef outputFormatDescription = NULL;

    CVPixelBufferRef testPixelBuffer = NULL;

    CVPixelBufferPoolCreatePixelBufferWithAuxAttributes( kCFAllocatorDefault, _bufferPool, _bufferPoolAuxAttributes, &testPixelBuffer );

    if ( ! testPixelBuffer ) {

        NSLog( @"Problem creating a pixel buffer." );

        success = NO;

        goto bail;

    }

    CMVideoFormatDescriptionCreateForImageBuffer( kCFAllocatorDefault, testPixelBuffer, &outputFormatDescription );

    _outputFormatDescription = outputFormatDescription;

    CFRelease( testPixelBuffer );

bail:

    if ( ! success ) {

        [self deleteBuffers];

    }

    return success;

}

- (void)deleteBuffers

{

    if ( _bufferPool ) {

        CFRelease( _bufferPool );

        _bufferPool = NULL;

    }

    if ( _bufferPoolAuxAttributes ) {

        CFRelease( _bufferPoolAuxAttributes );

        _bufferPoolAuxAttributes = NULL;

    }

    if ( _outputFormatDescription ) {

        CFRelease( _outputFormatDescription );

        _outputFormatDescription = NULL;

    }

    if ( _rgbColorSpace ) {

        CFRelease( _rgbColorSpace );

        _rgbColorSpace = NULL;

    }

    _ciContext = nil;

    _rosyFilter = nil;

}

static CVPixelBufferPoolRef createPixelBufferPool( int32_t width, int32_t height, OSType pixelFormat, int32_t maxBufferCount )

{

    CVPixelBufferPoolRef outputPool = NULL;

    NSDictionary *sourcePixelBufferOptions = @{ (id)kCVPixelBufferPixelFormatTypeKey : @(pixelFormat),

                                                (id)kCVPixelBufferWidthKey : @(width),

                                                (id)kCVPixelBufferHeightKey : @(height),

                                                (id)kCVPixelFormatOpenGLESCompatibility : @(YES),

                                                (id)kCVPixelBufferIOSurfacePropertiesKey : @{ /*empty dictionary*/ } };

    NSDictionary *pixelBufferPoolOptions = @{ (id)kCVPixelBufferPoolMinimumBufferCountKey : @(maxBufferCount) };

    CVPixelBufferPoolCreate( kCFAllocatorDefault, (__bridge CFDictionaryRef)pixelBufferPoolOptions, (__bridge CFDictionaryRef)sourcePixelBufferOptions, &outputPool );

    return outputPool;

}

static CFDictionaryRef createPixelBufferPoolAuxAttributes( int32_t maxBufferCount )

{

    // CVPixelBufferPoolCreatePixelBufferWithAuxAttributes() will return kCVReturnWouldExceedAllocationThreshold if we have already vended the max number of buffers

    NSDictionary *auxAttributes = [[NSDictionary alloc] initWithObjectsAndKeys:@(maxBufferCount), (id)kCVPixelBufferPoolAllocationThresholdKey, nil];

    return CFBridgingRetain( auxAttributes );

}

static void preallocatePixelBuffersInPool( CVPixelBufferPoolRef pool, CFDictionaryRef auxAttributes )

{

    // Preallocate buffers in the pool, since this is for real-time display/capture

    NSMutableArray *pixelBuffers = [[NSMutableArray alloc] init];

    while ( 1 )

    {

        CVPixelBufferRef pixelBuffer = NULL;

        OSStatus err = CVPixelBufferPoolCreatePixelBufferWithAuxAttributes( kCFAllocatorDefault, pool, auxAttributes, &pixelBuffer );

        if ( err == kCVReturnWouldExceedAllocationThreshold ) {

            break;

        }

        assert( err == noErr );

        [pixelBuffers addObject:CFBridgingRelease( pixelBuffer )];

    }

    [pixelBuffers removeAllObjects];

}

@end