绘制时GLKView为空白

时间:2016-09-18 23:54:33

标签: ios xcode uitableview glkview eaglcontext

我正在尝试使用GLKView将图像放入UITableViewCell来绘制图像。

我在故事板中有一个原型单元格,我有一个GLKView。它没有选中Enable setNeedsDisplay。

原型单元格有一个名为PhotoTableViewCell的自定义类

import UIKit
import GLKit

class PhotoTableViewCell: UITableViewCell {

  var eaglContext:EAGLContext!
  var ciContext:CIContext!
  var myImage:CIImage!

  @IBOutlet weak var photoGlView: GLKView!
  @IBOutlet weak var timeLabel: UILabel!
  @IBOutlet weak var cameraLabel: UILabel!
  @IBOutlet weak var notesLabel: UILabel!

  override func layoutSubviews() {
     self.photoGlView.delegate = self
 }

}

 extension PhotoTableViewCell: GLKViewDelegate {
   override func draw(_ rect: CGRect) {
       let drawableRectSize = CGSize(width: 200, height: 200)// width:   photoGlView.drawableWidth, height: photoGlView.drawableHeight)

      let drawableRect = CGRect(origin: CGPoint.zero, size: drawableRectSize)
      print("rect ->\(drawableRect)")
      print("rect size -> \(drawableRectSize)")
      ciContext.draw(myImage, in: drawableRect, from: myImage.extent)
      print("drawing rect my image =\(photoGlView)")
  }

  func glkView(_ view: GLKView, drawIn rect: CGRect) {
      let drawableRectSize = CGSize(width: view.drawableWidth, height: view.drawableHeight)
      let drawableRect = CGRect(origin: CGPoint.zero, size: drawableRectSize)
      ciContext.draw(myImage, in: drawableRect, from: myImage.extent)
      print("drawing")
  }
}

这用于UITableViewController

class PhotosTableViewController: UITableViewController {

  var cameraId:Int   = 1
  var photos:[Photo] = []
  var eaglContext:EAGLContext!
  var ciContext:CIContext!

override func viewDidLoad() {
    super.viewDidLoad()
    self.eaglContext = EAGLContext(api: .openGLES2)
    self.ciContext = CIContext(eaglContext: eaglContext!)

}

.... 

   override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 
      let cell = tableView.dequeueReusableCell(withIdentifier: "photoCell") as! PhotoTableViewCell
      let photo = photos[indexPath.row]
      if let image = photo.getLightImage()  {
          cell.ciContext      = ciContext
          cell.eaglContext    = eaglContext
          cell.myImage        = image
          cell.photoGlView.display()
      }
      cell.cameraLabel.text = AppService.shared.getCameraName(id: photo.cameraId)
      cell.timeLabel.text   = "Taken: \(photo.uploaded?.niceTime() ?? "")"
      return cell
}

当我导航到TableView时,我得到以下日志语句

rect ->(0.0, 0.0, 200.0, 200.0)
rect size -> (200.0, 200.0)
drawing rect my image =Optional(<GLKView: 0x1560bed0; frame = (0 0; 191 253); clipsToBounds = YES; opaque = NO; autoresize = RM+BM; tintColor =  UIDeviceRGBColorSpace 0 0 0 1; layer = <CAEAGLLayer: 0x1560e530>>)
rect ->(0.0, 0.0, 200.0, 200.0)
rect size -> (200.0, 200.0)
drawing rect my image =Optional(<GLKView: 0x156044f0; frame = (0 0; 191 253); clipsToBounds = YES; opaque = NO; autoresize = RM+BM; tintColor = UIDeviceRGBColorSpace 0 0 0 1; layer = <CAEAGLLayer: 0x15604610>>)

我的问题是为什么视图空白?我确信有一个图像,glkView在正确的位置(我已经使用Xcode中的预览工具进行了检查)

为什么要调用draw(rect :)而不是glkView(view:GLKView,drawIn rect:CGRect)?

我在运行iOS 9.3的iPhone 5上使用Xcode 8,swift 3,任何帮助都非常感谢

1 个答案:

答案 0 :(得分:1)

我不确定Xcode是否会以某种方式自动处理这个问题,或者默认情况下是否激活了上下文,但是在我迄今为止我唯一的OpenGL项目中,我不得不使用:

[EAGLContext setCurrentContext:ciContext];

每当我需要我的上下文激活时。