public UIImage Capture()
{
// This is from: https://developer.apple.com/library/ios/#qa/qa2010/qa1704.html
int backingWidth, backingHeight;
// Bind the color renderbuffer used to render the OpenGL ES view
// If your application only creates a single color renderbuffer which is already bound at this point,
// this call is redundant, but it is needed if you're dealing with multiple renderbuffers.
// Note, replace "_colorRenderbuffer" with the actual name of the renderbuffer object defined in your class.
gl.BindRenderbuffer(All.RenderbufferOes, Renderbuffer);
// Get the size of the backing CAEAGLLayer
gl.GetRenderbufferParameter(All.RenderbufferOes, All.RenderbufferWidthOes, out backingWidth);
gl.GetRenderbufferParameter(All.RenderbufferOes, All.RenderbufferHeightOes, out backingHeight);
int width = backingWidth, height = backingHeight;
int dataLength = width * height * 4;
byte[] data = new byte [dataLength];
// Read pixel data from the framebuffer
gl.PixelStore(All.PackAlignment, 4);
gl.ReadPixels(0, 0, width, height, All.Rgba, All.UnsignedByte, data);
// Create a CGImage with the pixel data
// If your OpenGL ES content is opaque, use kCGImageAlphaNoneSkipLast to ignore the alpha channel
// otherwise, use kCGImageAlphaPremultipliedLast
using (var data_provider = new CGDataProvider(data, 0, data.Length)) {
using (var colorspace = CGColorSpace.CreateDeviceRGB()) {
using (var iref = new CGImage(width, height, 8, 32, width * 4, colorspace,
(CGImageAlphaInfo)((int)CGBitmapFlags.ByteOrder32Big | (int)CGImageAlphaInfo.PremultipliedLast),
data_provider, null, true, CGColorRenderingIntent.Default)) {
// OpenGL ES measures data in PIXELS
// Create a graphics context with the target size measured in POINTS
int widthInPoints, heightInPoints;
float scale = (float)ContentScaleFactor;
widthInPoints = (int)(width / scale);
heightInPoints = (int)(height / scale);
UIGraphics.BeginImageContextWithOptions(new System.Drawing.SizeF(widthInPoints, heightInPoints), false, scale);
try {
var cgcontext = UIGraphics.GetCurrentContext();
// UIKit coordinate system is upside down to GL/Quartz coordinate system
// Flip the CGImage by rendering it to the flipped bitmap context
// The size of the destination area is measured in POINTS
cgcontext.SetBlendMode(CGBlendMode.Copy);
cgcontext.DrawImage(new System.Drawing.RectangleF(0, 0, widthInPoints, heightInPoints), iref);
// Retrieve the UIImage from the current context
var image = UIGraphics.GetImageFromCurrentImageContext();
return(image);
} finally {
UIGraphics.EndImageContext();
}
}
}
}
}
