混编的时候可以用swift调用

#import <AVFoundation/AVFoundation.h>
#import <MetalKit/MetalKit.h>
#import <MetalPerformanceShaders/MetalPerformanceShaders.h>

NS_ASSUME_NONNULL_BEGIN

@interface MetalTextureManager : NSObject

+ (instancetype)shareManager;

- (void)setCMSampleBufferRef:(CMSampleBufferRef)sampleBuffer tag:(NSInteger)tag complete:(nullable void(^)(id <MTLTexture> tex,CMSampleBufferRef buffer))complete;

@end

NS_ASSUME_NONNULL_END



#import "MetalTextureManager.h"

@interface MetalTextureManager ()

@property (nonatomic, strong) id <MTLDevice> device;
@property (nonatomic, strong) dispatch_queue_t processQueue;// 处理队列
@property (nonatomic, assign) CVMetalTextureCacheRef textureCache;// 纹理缓存区
@property (nonatomic, strong) id<MTLCommandQueue> commandQueue;// 命令队列
@property (nonatomic, strong) id<MTLTexture> texture;// 纹理


@end


@implementation MetalTextureManager


+ (instancetype)shareManager {
    static MetalTextureManager *manager = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        manager = [[MetalTextureManager alloc] init];
        
        [manager setup];
    });
    return manager;
}

- (void)setup {
    [self setupMetal];
}

- (void)setCMSampleBufferRef:(CMSampleBufferRef)sampleBuffer tag:(NSInteger)tag complete:(nullable void (^)(id<MTLTexture> _Nonnull, CMSampleBufferRef))complete {
    //metal渲染
    [self metalRenderWithSampleBuffer:sampleBuffer complete:^(id<MTLTexture> tex, CMSampleBufferRef buffer) {
        if (complete != nil) {
            complete(tex,buffer);
        }
    }];
    
}

- (void)setupMetal {
    
    // 1.获取MTKView
    self.device = MTLCreateSystemDefaultDevice();
    
    // 3.创建命令队列
    self.commandQueue = [self.device newCommandQueue];
    
    // 4.创建Core Video的Metal纹理缓存区
    CVMetalTextureCacheCreate(NULL, NULL, self.device, NULL, &_textureCache);
}


- (void)metalRenderWithSampleBuffer:(CMSampleBufferRef)sampleBuffer complete:(nullable void(^)(id<MTLTexture> tex, CMSampleBufferRef buffer))complete {
    
    
    //    NSLog(@"----线程3333----%@----",[NSThread currentThread]);
    
    // 1.从sampleBuffer获取视频像素缓存区对象
    CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    
    if (pixelBuffer == nil) {
        return;
    }
    
    CVPixelBufferLockBaseAddress(pixelBuffer, 0);
    // 2.获取捕捉视频的宽和高
    size_t width = CVPixelBufferGetWidth(pixelBuffer);
    size_t height = CVPixelBufferGetHeight(pixelBuffer);
    
    // 4.从现有图像缓冲区创建核心视频Metal纹理缓冲区
    CVMetalTextureRef tmpTexture = NULL;
    CVReturn status = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, self.textureCache, pixelBuffer, NULL, MTLPixelFormatBGRA8Unorm, width, height, 0, &tmpTexture);
    
    // 判断纹理缓冲区是否创建成功
    if(status == kCVReturnSuccess) {
        // 6.返回纹理缓冲区的Metal纹理对象
        self.texture = CVMetalTextureGetTexture(tmpTexture);
        if (complete != nil && self.texture != nil) {
            complete(self.texture,sampleBuffer);
        }
        // 7.使用完毕，则释放纹理缓冲区
        CFRelease(tmpTexture);
        tmpTexture = NULL;
        self.texture = NULL;
    }
    
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
}

@end

使用示例

可以传递给unity去渲染（用callback将texture纹理传递给unity让其去渲染）

typedef void (*dp_updateTextureCallback_t)(void *texture, int screenId, int width, int height);

//在USBServiceOC.h里面声明
@property (nonatomic, copy, nullable) void (^screenRecordSampleBufferBlock1)(int screenId,CMSampleBufferRef sampleBuffer);

void drawRenderWithTextureIDFromUnity(dp_updateTextureCallback_t callback) {
    __weak service *service = [USBServiceOC shareManager];
    //这里是个获取SampleBuffer的回调block，可以在获取SampleBuffer的调用【self.screenRecordSampleBufferBlock1(0, sampleBuffer)】
    service.screenRecordSampleBufferBlock1 = ^(int screenId, CMSampleBufferRef sampleBuffer) {
        if (service.isNOCallBack == NO && service.isStopRecording == NO) {
            [service.metalTextureManager setCMSampleBufferRef:sampleBuffer tag:0 complete:^(id<MTLTexture>  _Nonnull texture, CMSampleBufferRef  _Nonnull buffer) {
                id<MTLTexture> tmpTexture = texture;
                if (callback != nil) {
                    callback((__bridge void *)texture,0,int(texture.width),int(texture.height));
                }
                tmpTexture = nil;
            }];
        }
    };
}

[service.metalTextureManager setCMSampleBufferRef:sampleBuffer tag:0 complete:^(id<MTLTexture>  _Nonnull texture, CMSampleBufferRef  _Nonnull buffer) {
        id<MTLTexture> tmpTexture = texture;
        if (callback != nil) {
             callback((__bridge void *)texture,0,int(texture.width),int(texture.height));
        }
        tmpTexture = nil;
}];