In my Opzioni vector (in italian Options) you can see how i manage the switch to enable the screenshot.
But you don't need it.
Just copy the C++ function as a mixed OBJ C C++.
You need to import some framework of course.
//*****************************************
// SCREENSHOTS
//*****************************************
UIImage* GLScreenShot(){
Opzioni[0].screenshot = 1;
GLint backingWidth, backingHeight;
// Get the size of the backing CAEAGLLayer
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
NSInteger x = 0, y = 0, width = backingWidth, height = backingHeight;
NSInteger dataLength = width * height * 4;
GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte));
// Read pixel data from the framebuffer
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, 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
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef iref = CGImageCreate (width, height, 8, 32, width * 4, colorspace,
// Fix from Apple implementation
// (was: kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast).
kCGBitmapByteOrderDefault,
//kCGImageAlphaNoneSkipLast,
ref, NULL, true, kCGRenderingIntentDefault);
// OpenGL ES measures data in PIXELS
// Create a graphics context with the target size measured in POINTS
NSInteger widthInPoints, heightInPoints;
CGFloat scale = g_View.view.contentScaleFactor;
widthInPoints = width / scale;
heightInPoints = height / scale;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(widthInPoints, heightInPoints), NO, scale);
CGContextRef cgcontext = UIGraphicsGetCurrentContext();
// 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
CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);
CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, widthInPoints, heightInPoints), iref);
// Retrieve the UIImage from the current context
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Clean up
free(data);
CFRelease(ref);
CFRelease(colorspace);
CGImageRelease(iref);
//Opzioni[0].screenshot = 0;
if(Opzioni[0].autosave_screenshots) UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
return image;
}
if(Opzioni[0].screenshot == 0){
agk::Sync();
} else if(Opzioni[0].screenshot == 1){
agk::Update();
agk::Render();
UIImage *_im = GLScreenShot();
if(Opzioni[0].auto_fbscreen) [g_View FBPostScreenShot:_im];
Opzioni[0].screenshot = 0;
agk::Swap();
}
This is how to make a screenshot using C++ mixed with Obj C.
If you want also a way to port NSImage to AppGameKit image don't hesitate to ask.
Long life to Steve!