metal framework on macOS

Question

私は基本的にMetalフレームでBGRA形式のビデオフレームをレンダリングするシンプルなテクスチャディスプレイを作成しています。私は、Metal WWDCセッションで述べたのと同じ手順に従います。レンダリングエンコーダの作成には問題があります。私のコードは、行でこのコードがクラッシュし ID renderCmdEncoder = [commandBuffer renderCommandEncoderWithDescriptor：renderPassDesc] "いいえが見つかりレンダリングターゲット" と言って

id <MTLDevice> device = MTLCreateSystemDefaultDevice(); 
id<MTLCommandQueue> commandQueue = [device newCommandQueue]; 

id<MTLLibrary> library = [device newDefaultLibrary]; 

// Create Render Command Descriptor. 
MTLRenderPipelineDescriptor* renderPipelineDesc = [MTLRenderPipelineDescriptor new]; 
renderPipelineDesc.colorAttachments[0].pixelFormat = MTLPixelFormatBGRA8Unorm; 
renderPipelineDesc.vertexFunction = [library newFunctionWithName:@"basic_vertex"]; 
renderPipelineDesc.fragmentFunction = [library newFunctionWithName:@"basic_fragment"]; 

NSError* error = nil; 
id<MTLRenderPipelineState> renderPipelineState = [device newRenderPipelineStateWithDescriptor:renderPipelineDesc 
                   error:&error]; 

id<MTLCommandBuffer> commandBuffer = [commandQueue commandBuffer]; 

MTLRenderPassDescriptor* renderPassDesc = [MTLRenderPassDescriptor renderPassDescriptor]; 

id<CAMetalDrawable> drawable = [_metalLayer nextDrawable]; 

MTLRenderPassColorAttachmentDescriptor* colorAttachmentDesc = [MTLRenderPassColorAttachmentDescriptor new]; 
colorAttachmentDesc.texture = drawable.texture; 
colorAttachmentDesc.loadAction = MTLLoadActionLoad; 
colorAttachmentDesc.storeAction = MTLStoreActionStore; 
colorAttachmentDesc.clearColor = MTLClearColorMake(0, 0, 0, 1); 

[renderPassDesc.colorAttachments setObject:colorAttachmentDesc atIndexedSubscript:0]; 

[inTexture replaceRegion:region 
     mipmapLevel:0 
      withBytes:imageBytes 
     bytesPerRow:CVPixelBufferGetBytesPerRow(_image)]; 

id<MTLRenderCommandEncoder> renderCmdEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDesc]; 

[renderCmdEncoder setRenderPipelineState:_renderPipelineState]; 
[renderCmdEncoder endEncoding]; 

です。 レンダーターゲットを設定する場所と方法を理解できません。

Answer 1

これは完全に機能します。あなたはそれを実装するヘルプが必要な場合、私に知らせて：

@import UIKit; 
@import AVFoundation; 
@import CoreMedia; 
#import <MetalKit/MetalKit.h> 
#import <Metal/Metal.h> 
#import <MetalPerformanceShaders/MetalPerformanceShaders.h> 

@interface ViewController : UIViewController <MTKViewDelegate, AVCaptureVideoDataOutputSampleBufferDelegate> { 
    NSString *_displayName; 
    NSString *serviceType; 
} 

@property (retain, nonatomic) SessionContainer *session; 
@property (retain, nonatomic) AVCaptureSession *avSession; 

@end; 

#import "ViewController.h" 

@interface ViewController() { 
    MTKView *_metalView; 

    id<MTLDevice> _device; 
    id<MTLCommandQueue> _commandQueue; 
    id<MTLTexture> _texture; 

    CVMetalTextureCacheRef _textureCache; 
} 

@property (strong, nonatomic) AVCaptureDevice *videoDevice; 
@property (nonatomic) dispatch_queue_t sessionQueue; 

@end 

@implementation ViewController 

- (void)viewDidLoad { 
    NSLog(@"%s", __PRETTY_FUNCTION__); 
    [super viewDidLoad]; 

    _device = MTLCreateSystemDefaultDevice(); 
    _metalView = [[MTKView alloc] initWithFrame:self.view.bounds]; 
    [_metalView setContentMode:UIViewContentModeScaleAspectFit]; 
    _metalView.device = _device; 
    _metalView.delegate = self; 
    _metalView.clearColor = MTLClearColorMake(1, 1, 1, 1); 
    _metalView.colorPixelFormat = MTLPixelFormatBGRA8Unorm; 
    _metalView.framebufferOnly = NO; 
    _metalView.autoResizeDrawable = NO; 

    CVMetalTextureCacheCreate(NULL, NULL, _device, NULL, &_textureCache); 

    [self.view addSubview:_metalView]; 

    self.sessionQueue = dispatch_queue_create("session queue", DISPATCH_QUEUE_SERIAL); 

    if ([self setupCamera]) { 
     [_avSession startRunning]; 
    } 
} 

- (BOOL)setupCamera { 
    NSLog(@"%s", __PRETTY_FUNCTION__); 
    @try { 
     NSError * error; 

      _avSession = [[AVCaptureSession alloc] init]; 
      [_avSession beginConfiguration]; 
      [_avSession setSessionPreset:AVCaptureSessionPreset640x480]; 

      // get list of devices; connect to front-facing camera 
      self.videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
      if (self.videoDevice == nil) return FALSE; 

      AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:self.videoDevice error:&error]; 
      [_avSession addInput:input]; 

      dispatch_queue_t sampleBufferQueue = dispatch_queue_create("CameraMulticaster", DISPATCH_QUEUE_SERIAL); 

      AVCaptureVideoDataOutput * dataOutput = [[AVCaptureVideoDataOutput alloc] init]; 
      [dataOutput setAlwaysDiscardsLateVideoFrames:YES]; 
      [dataOutput setVideoSettings:@{(id)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA)}]; 
      [dataOutput setSampleBufferDelegate:self queue:sampleBufferQueue]; 

      [_avSession addOutput:dataOutput]; 
      [_avSession commitConfiguration]; 
    } @catch (NSException *exception) { 
     NSLog(@"%s - %@", __PRETTY_FUNCTION__, exception.description); 
     return FALSE; 
    } @finally { 
     return TRUE; 
    } 

} 

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection 
{ 
    CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    { 
     size_t width = CVPixelBufferGetWidth(pixelBuffer); 
     size_t height = CVPixelBufferGetHeight(pixelBuffer); 

     CVMetalTextureRef texture = NULL; 
     CVReturn status = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, _textureCache, pixelBuffer, NULL, MTLPixelFormatBGRA8Unorm, width, height, 0, &texture); 
     if(status == kCVReturnSuccess) 
     { 
      _metalView.drawableSize = CGSizeMake(width, height); 
      _texture = CVMetalTextureGetTexture(texture); 
      _commandQueue = [_device newCommandQueue]; 
      CFRelease(texture); 
     } 
    } 
} 

- (void)drawInMTKView:(MTKView *)view { 
    // creating command encoder 
    if (_texture) { 
     id<MTLCommandBuffer> commandBuffer = [_commandQueue commandBuffer]; 
     id<MTLTexture> drawingTexture = view.currentDrawable.texture; 

     // set up and encode the filter 
     MPSImageGaussianBlur *filter = [[MPSImageGaussianBlur alloc] initWithDevice:_device sigma:5]; 

     [filter encodeToCommandBuffer:commandBuffer sourceTexture:_texture destinationTexture:drawingTexture]; 

     // committing the drawing 
     [commandBuffer presentDrawable:view.currentDrawable]; 
     [commandBuffer commit]; 
     _texture = nil; 
    } 
} 

- (void)mtkView:(MTKView *)view drawableSizeWillChange:(CGSize)size { 

} 

@end 

Answer 2

あなたはMTKView object.thisから現在のレンダーパス記述子オブジェクトを使用して、新しいレンダーパス記述子を作成するのは、以下の点

1.Insteadのいずれかを試してみてくださいレンダーパス記述子すでにconfigured.youが

if let currentPassDesc = view.currentRenderPassDescriptor, 
let currentDrawable = view.currentDrawable 
{ 
let renderCommandEncoder =   

commandBuffer.makeRenderCommandEncoder(descriptor: currentPassDesc) 


renderCommandEncoder.setRenderPipelineState(renderPipeline) 

//set vertex buffers and call draw apis 
....... 
....... 
commandBuffer.present(currentDrawable) 

} 

2.you below-与えられたサンプルコード描画可能オブジェクトの質感によってその色の添付ファイルを設定し、新しいレンダーパス記述子を作成しているがanything.try設定する必要はありませんでしょうdoiの代わりにこれを行うには、新しいテクスチャオブジェクトを作成し、このテクスチャの使用方法をレンダリングターゲットとして設定する必要があります。新しいテクスチャでレンダリングされるコンテンツを取得しますが、スクリーンには表示されません。テクスチャの内容を描画可能テクスチャにコピーしてから描画可能にします。以下

レンダーターゲットせるコードである -

renderPassDescriptor.colorAttachments[0].clearColor = 

MTLClearColor(red: 

0.0,green: 0.0,blue: 0.0,alpha: 1.0) 
renderPassDescriptor.colorAttachments[0].loadAction = .clear 
renderPassDescriptor.colorAttachments[0].storeAction = .store 

renderPassDescriptor.depthAttachment.clearDepth = 1.0 
renderPassDescriptor.depthAttachment.loadAction = .clear 
renderPassDescriptor.depthAttachment.storeAction = .dontCare 

let view = self.view as!MTKView 
let textDesc = MTLTextureDescriptor.texture2DDescriptor(pixelFormat: 

.bgra8Unorm, width: Int(view.frame.width), 
height: Int(view.frame.height), mipmapped: false) 
textDesc.depth = 1 
//see below line  
textDesc.usage = 
[MTLTextureUsage.renderTarget,MTLTextureUsage.shaderRead] 
textDesc.storageMode = .private 
mainPassFrameBuffer = device.makeTexture(descriptor: textDesc) 
renderPassDescriptor.colorAttachments[0].texture = mainPassFrameBuffer