openGL ES视网膜支持 [英] openGL ES retina support

问题描述

我正试图让avTouch示例代码应用程序在视网膜显示屏上运行。有没有人这样做过？

I'm trying to get the avTouch sample code app to run on the retina display. Has anyone done this?

在CALevelMeter课程中，我尝试了以下内容：

In the CALevelMeter class, I've tried the following:

- (id)initWithCoder:(NSCoder *)coder {
 if (self = [super initWithCoder:coder]) {
      CGFloat f = self.contentScaleFactor;
      if ([self respondsToSelector:@selector(contentScaleFactor)])
      {
           self.contentScaleFactor = [[UIScreen mainScreen] scale];
      }
      f = self.contentScaleFactor;

      _showsPeaks = YES;
      _channelNumbers = [[NSArray alloc] initWithObjects:[NSNumber numberWithInt:0], nil];
      _vertical = NO;
      _useGL = YES;
      _meterTable = new MeterTable(kMinDBvalue);
      [self layoutSubLevelMeters];
      [self registerForBackgroundNotifications];
 }
 return self;

}

并设置contentScaleFactor到2。很好，这是预期的。但是在layoutSubviews中，CALevelMeter框架仍然是应该的1/2。

and it sets the contentScaleFactor to "2". Great, that was expected. But then in the layoutSubviews, CALevelMeter frame is still 1/2 of what it should be.

任何想法？

推荐答案

框架是以点为单位，而不是像素。当比例因子应用于托管CAEAGLLayer的UIView时，它将是像素的两倍，但其帧点大小将保持不变。

Frames are in points, not pixels. When a scale factor is applied to the UIView hosting your CAEAGLLayer, it will be double the pixels, but its frame point size will remain the same.

如果你看一下使用如下代码附加到CAEAGLLayer的颜色渲染缓冲区的背景宽度和高度：

If you look at the backing width and height for the color renderbuffer attached to the CAEAGLLayer using code like the following:

glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);

你应该看到Retina显示屏上渲染缓冲区的宽度和高度是它们的两倍。在标准的iPhone显示屏上。

you should see that the width and height of the renderbuffer on a Retina display are twice the values they are on a standard iPhone display.

上面显示的代码应该会在Retina显示屏上产生漂亮，清晰的渲染效果。

The code you show above should cause nice, sharp rendering on a Retina display.

编辑（12/22/2010）：回答您的进一步问题，查看avTouch示例代码显示该代码的当前版本在查找时出错提升OpenGL托管视图的范围，而不是使用renderbuffer的支持宽度和高度。使用非1.0比例因子，这将导致OpenGL内容以一半大小绘制。

EDIT (12/22/2010): In response to your further question, looking at the avTouch sample code shows that the current version of that code makes a mistake in looking up the bounds of the OpenGL-hosting view, rather than using the backing width and height of the renderbuffer. With a non-1.0 scale factor, this will cause the OpenGL content to be drawn at half size.

要解决此问题，请替换，代码如下：

To fix this, replace the appropriate section within _drawView in GLLevelMeter with the following code:

if (_vertical)
{
    glTranslatef(0., _backingWidth, 0.);
    glScalef(1., -1., 1.);
    bds = CGRectMake(0., 0., _backingWidth, _backingHeight);
} else {
    glTranslatef(0., _backingHeight, 0.);
    glRotatef(-90., 0., 0., 1.);
    bds = CGRectMake(0., 0., _backingHeight, _backingWidth);
}

这将导致所有内容在适当的像素空间中工作，并导致清脆在均衡器中以正确的大小渲染。我已就此提交了一份错误报告。

This will cause everything to work in the appropriate pixel space, and lead to crisp rendering at the correct size in the equalizer. I've filed a bug report on this.

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