Vision Camera

//
//  ObjcViewController.m
//  FilterCam
//
//  Created by B Gay on 11/3/17.
//  Copyright © 2017 B Gay. All rights reserved.
//

#import "ObjcViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <CoreImage/CoreImage.h>
#import <Vision/Vision.h>
#import "VisionFace.h"

@interface ObjcViewController () <AVCaptureVideoDataOutputSampleBufferDelegate>
@property (nonatomic, strong) AVCaptureSession *captureSession;
@property (nonatomic, strong) AVCaptureDevice *backCamera;
@property (nonatomic, strong) AVCaptureDevice *frontCamera;
@property (nonatomic, strong) AVCaptureDevice *currentCamera;
@property (nonatomic, strong) AVCapturePhotoOutput *photoOutput;
@property (nonatomic, assign) AVCaptureVideoOrientation orientation;
@property (nonatomic, strong) CIContext *context;
@property (weak, nonatomic) IBOutlet UIImageView *filteredImage;

@end

@implementation ObjcViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.context = [[CIContext alloc] init];
    [self setupDevice];
    [self setupInputOutput];
}

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];
    self.orientation = (AVCaptureVideoOrientation)[UIApplication sharedApplication].statusBarOrientation;
}

- (void)setupDevice {
    AVCaptureDeviceDiscoverySession *deviceDiscoverySession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
    NSArray *devices = deviceDiscoverySession.devices;
    for (AVCaptureDevice *device in devices) {
        if (device.position == AVCaptureDevicePositionBack) {
            self.backCamera = device;
        }
        else if (device.position == AVCaptureDevicePositionFront) {
            self.frontCamera = device;
        }
    }
    self.currentCamera = self.frontCamera;
}

- (void)setupInputOutput {
    self.captureSession = [[AVCaptureSession alloc] init];
    AVCaptureDeviceInput *captureDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:self.currentCamera error:nil];
    self.captureSession.sessionPreset = AVCaptureSessionPreset1280x720;
    if ([self.captureSession canAddInput:captureDeviceInput]) {
        [self.captureSession addInput:captureDeviceInput];
    }
    
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    [videoOutput setSampleBufferDelegate:self queue:dispatch_queue_create("CameraCaptureSampleBufferDelegateQueue", NULL)];
    if ([self.captureSession canAddOutput:videoOutput]) {
        [self.captureSession addOutput:videoOutput];
    }
    [self.captureSession startRunning];
}

- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    connection.videoOrientation = self.orientation;
    CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    CIImage *cameraImage = [[CIImage alloc] initWithCVPixelBuffer:pixelBuffer];
    
    NSMutableDictionary<VNImageOption, id> *requestOptions = [NSMutableDictionary dictionary];
    CFTypeRef cameraIntrinsicData = CMGetAttachment(sampleBuffer,
                                                    kCMSampleBufferAttachmentKey_CameraIntrinsicMatrix,
                                                    nil);
    requestOptions[VNImageOptionCameraIntrinsics] = (__bridge id)(cameraIntrinsicData);
        
    CGImageRef cgImage = [self.context createCGImage:cameraImage fromRect:cameraImage.extent];
    VNDetectFaceLandmarksRequest *landmarksRequest =
    [[VNDetectFaceLandmarksRequest alloc] initWithCompletionHandler:^(VNRequest *request, NSError *error) {
        if (error != nil) {
            NSLog(@"Error while detecting face landmarks: %@", error);
        } else {
            dispatch_async(dispatch_get_main_queue(), ^{
                self.filteredImage.layer.sublayers = @[];
                NSArray *faces = [self handRequest:request inImage:cameraImage];
                if (faces.count) {
                    [self drawFaces:faces];
                }
            });
        }
    }];
    
    dispatch_async(dispatch_get_main_queue(), ^{
        self.filteredImage.image = [UIImage imageWithCGImage:cgImage];
    });
    VNImageRequestHandler *requestHandler = [[VNImageRequestHandler alloc] initWithCVPixelBuffer:pixelBuffer options:requestOptions];
    NSError *error;
    [requestHandler performRequests:@[landmarksRequest] error:&error];
}

- (NSArray <VisionFace *> *)handRequest:(VNRequest *)request inImage:(CIImage *)image {
    NSMutableArray *faces = [NSMutableArray new];
    for (VNFaceObservation *observation in request.results) {
        CGRect faceRect = observation.boundingBox;
        CGRect convertedFaceRect = CGRectMake(image.extent.size.width * faceRect.origin.x, image.extent.size.height * (1 - faceRect.origin.y - faceRect.size.height), image.extent.size.width * faceRect.size.width, image.extent.size.height * faceRect.size.height);
        VisionFace *visionFace = [VisionFace new];
        visionFace.rect = convertedFaceRect;
        visionFace.landmarks = observation.landmarks;
        [faces addObject:visionFace];
    }
    return faces;
}

- (void)drawFaces:(NSArray <VisionFace *>*)faces {
    for (VisionFace *face in faces) {
        CAShapeLayer *boundingBoxLayer = [[CAShapeLayer alloc] init];
        boundingBoxLayer.path = [UIBezierPath bezierPathWithRect:face.rect].CGPath;
        boundingBoxLayer.strokeColor = [UIColor redColor].CGColor;
        boundingBoxLayer.fillColor = [UIColor clearColor].CGColor;
        [self.filteredImage.layer addSublayer:boundingBoxLayer];
        CAShapeLayer *shapeLayer = [self layerFromFace:face inRegion:face.landmarks];
        [self.filteredImage.layer addSublayer:shapeLayer];
    }
}

- (CAShapeLayer *) layerFromFace:(VisionFace *)face inRegion:(VNFaceLandmarks2D *)region {
    CAShapeLayer *layer = [[CAShapeLayer alloc] init];
    layer.strokeColor = [UIColor redColor].CGColor;
    layer.fillColor = [UIColor clearColor].CGColor;
    layer.lineWidth = 2.0;
    UIBezierPath *path = [[UIBezierPath alloc] init];
    
    for (NSInteger i = 0; i < region.allPoints.pointCount; i++) {
        VNFaceLandmarkRegion2D * subregion = region.allPoints;
        [path moveToPoint:[self absolutePointInFace:face normalizedPoint:subregion.normalizedPoints[0]]];

        for (NSInteger j = 0; j< subregion.pointCount; j++) {
            CGPoint normalPoint = [self absolutePointInFace:face normalizedPoint:subregion.normalizedPoints[j]];
            [path addLineToPoint:normalPoint];
        }
    }
    
    layer.path = path.CGPath;
    return layer;
}

- (CGPoint)absolutePointInFace:(VisionFace *)face normalizedPoint:(CGPoint)point {
    return CGPointMake(face.rect.origin.x + point.x * face.rect.size.width, face.rect.origin.y + (1 - point.y) * face.rect.size.height);
}



@end


@interface VisionFace : NSObject
@property (nonatomic, assign) CGRect rect;
@property (nonatomic, assign) VNFaceLandmarks2D *landmarks;
@end