我在使用Isgl3d控制视图的UIImage快照时遇到了一些困难。似乎无论我做什么，我最终都会得到一个黑色方块。
我在视图中有一个工作相机视图和一个3D模型，我尝试使用缓冲方法和常规屏幕捕获来获取图像，但没有任何有效的结果。
有没有人有成功拍摄Isgl3d视图的源代码？
答案 0 :(得分：5)
以下是Apple的说明＆amp;将GL视图快照到UIImage的官方代码（考虑到视网膜显示，翻转的坐标等），我一直在成功使用它。当然，这不是特定于iSGL3D的，但只要您能够获得正确的上下文和帧缓冲区来绑定，它就应该做正确的事情。 （如页面所述，您必须确保在调用-presentRenderbuffer:之前拍摄快照，以便渲染缓冲区有效。）
https://developer.apple.com/library/ios/#qa/qa1704/_index.html
我对iSGL3D库只有一个粗略的熟悉，它看起来不像有明显的钩子让你渲染场景但不呈现它（或首先渲染到屏幕外缓冲区）。您可能需要进行干预的位置是您正在使用的-finalizeRender子类的Isgl3dGLContext方法，就在调用-presentRenderbuffer之前。这个上下文在这里是一个内部框架类，所以你可能需要在库中稍微改变一下来设置（比如说）一个代理来自视图和导演的上下文，最终要求你的应用程序在“现在”呼叫之前采取任何行动，在此期间您可以选择运行屏幕截图代码（如果您愿意），或者如果您不想这样做则不执行任何操作。
答案 1 :(得分：3)
这是你想要的吗？
这将从当前上下文和帧缓冲区获取屏幕截图，并将其保存到相册中。
如果您不想保存到相册，请在最后获得最终的UIImage。
还记得在完成绘图后，但在切换缓冲区之前调用它。
此外，如果您正在使用MSAA，则必须在glResolveMultisampleFramebufferAPPLE和新缓冲区绑定后调用它。
#ifdef AUTOSCREENSHOT
// callback for CGDataProviderCreateWithData
void releaseData(void *info, const void *data, size_t dataSize) {
free((void*)data);
}
// callback for UIImageWriteToSavedPhotosAlbum
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
NSLog(@"Save finished");
[image release];
}
-(void)saveCurrentScreenToPhotoAlbum {
int height = (int)screenSize.y*retina;
int width = (int)screenSize.x*retina;
NSInteger myDataLength = width * height * 4;
GLubyte *buffer = (GLubyte *) malloc(myDataLength);
GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
for(int y = 0; y <height; y++) {
for(int x = 0; x < width * 4; x++) {
buffer2[(int)((height - 1 - y) * width * 4 + x)] = buffer[(int)(y * 4 * width + x)];
}
}
free(buffer);
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer2, myDataLength, releaseData);
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
UIImage *image = [[UIImage alloc] initWithCGImage:imageRef];
CGImageRelease(imageRef);
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
#endif
我在播放时使用此代码来保存定时屏幕截图，因此我可以将神材料放入应用程序商店。
答案 2 :(得分：3)
我在我的某个应用中成功使用此代码段来执行OpenGL屏幕截图。
enum {
red,
green,
blue,
alpha
};
- (UIImage *)glToUIImage {
CGSize glSize = self.glView.bounds.size;
NSInteger bufDataLen = glSize.width * glSize.height * 4;
// Allocate array and read pixels into it.
GLubyte *buffer = (GLubyte *)malloc(bufDataLen);
glReadPixels(0, 0, glSize.width, glSize.height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
// We need to flip the image
NSUInteger maxRow = (NSInteger)glSize.height - 1;
NSUInteger bytesPerRow = (NSInteger)glSize.width * 4;
GLubyte *buffer2 = (GLubyte *)malloc(bufDataLen);
for(int y = maxRow; y >= 0; y--) {
for(int x = 0; x < bytesPerRow; x+=4) {
NSUInteger c0 = y * bytesPerRow + x;
NSUInteger c1 = (maxRow - y) * bytesPerRow + x;
buffer2[c0+red] = buffer[c1+red];
buffer2[c0+green] = buffer[c1+green];
buffer2[c0+blue] = buffer[c1+blue];
buffer2[c0+alpha] = buffer[c1+alpha];
}
}
free(buffer);
// Make data provider with data
CFDataRef imageData = CFDataCreate(NULL, buffer2, bufDataLen);
free(buffer2);
CGDataProviderRef provider = CGDataProviderCreateWithCFData(imageData);
CFRelease(imageData);
// Bitmap format
int bitsPerComponent = 8;
int bitsPerPixel = 32;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
// Create the CGImage
CGImageRef imageRef = CGImageCreate(glSize.width,
glSize.height,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider,
NULL,
NO,
renderingIntent);
// Clean up
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
// Convert to UIImage
UIImage *image = [[UIImage alloc] initWithCGImage:imageRef];
CGImageRelease(imageRef);
return [image autorelease];
}
确保在执行此操作之前绑定帧缓冲区，如此
glBindFramebufferOES(GL_FRAMEBUFFER_OES, myFrameBuffer);
glViewport(0, 0, myBackingWidth, myBackingHeight);
在呈现帧缓冲区之前调用-glToUIImage！
有关详细信息，Apple提供了sample code从OpenGL截取屏幕截图。
答案 3 :(得分：2)
我想出了这个可能的解决方案。你必须修改一下isgl3d库。
步骤如下：
1
为Isgl3dGLContext1创建委托：
在Isgl3dGLContext1.h
中@protocol ScreenShooterDelegate;
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>
#import "Isgl3dGLContext.h"
@interface Isgl3dGLContext1 : Isgl3dGLContext {
NSObject<ScreenShooterDelegate>* __unsafe_unretained delegate;
GLuint _colorRenderBuffer;
@private
EAGLContext * _context;
// The OpenGL names for the framebuffer and renderbuffer used to render to this view
GLuint _defaultFrameBuffer;
GLuint _depthAndStencilRenderBuffer;
GLuint _depthRenderBuffer;
GLuint _stencilRenderBuffer;
// OpenGL MSAA buffers
GLuint _msaaFrameBuffer;
GLuint _msaaColorRenderBuffer;
GLuint _msaaDepthAndStencilRenderBuffer;
GLuint _msaaDepthRenderBuffer;
GLuint _msaaStencilRenderBuffer;
}
- (id) initWithLayer:(CAEAGLLayer *) layer;
@property (assign) NSObject<ScreenShooterDelegate>* delegate;
@property BOOL takePicture;
@property GLuint colorRenderBuffer;
@end
@protocol ScreenShooterDelegate
@optional
- (void)takePicture;
@end
2
。将此代码添加到Isgl3dGLContext1.m：
@synthesize takePicture;
@synthesize colorRenderBuffer = _colorRenderBuffer;
行前[_context presentRenderbuffer：GL_RENDERBUFFER_OES]; in - （void）finalizeRender：
if(takePicture){
takePicture=NO;
if([delegate respondsToSelector:@selector(takePicture)]){
[delegate takePicture];
}
}
3将此代码放在要进行屏幕截图的类中：
In Class.h add <ScreenShooterDelegate>
方法Class.m
[Isgl3dDirector sharedInstance].antiAliasingEnabled = NO;
Photos3DAppDelegate *appDelegate = (Photos3DAppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate.inOutSceneView showSphere];
Isgl3dEAGLView* eaglview=(Isgl3dEAGLView*)[[Isgl3dDirector sharedInstance] openGLView];
Isgl3dGLContext1 * _glContext=(Isgl3dGLContext1*)[eaglview glContext];
_glContext.delegate=self;
_glContext.takePicture=YES;
在方法中 - （void）takePicture {}放置来自Apple的代码并在方法的末尾添加[Isgl3dDirector sharedInstance] .antiAliasingEnabled = YES; （如果你使用它的话）
//https://developer.apple.com/library/ios/#qa/qa1704/_index.html
-(void)takePicture{
NSLog(@"Creating Foto");
GLint backingWidth, backingHeight;
Isgl3dEAGLView* eaglview=(Isgl3dEAGLView*)[[Isgl3dDirector sharedInstance] openGLView];
//Isgl3dGLContext1 * _glContext=(Isgl3dGLContext1*)[eaglview glContext];
//glBindRenderbufferOES(GL_RENDERBUFFER_OES, _glContext.colorRenderBuffer);
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, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast,
ref, NULL, true, kCGRenderingIntentDefault);
// OpenGL ES measures data in PIXELS
// Create a graphics context with the target size measured in POINTS
NSInteger widthInPoints, heightInPoints;
if (NULL != UIGraphicsBeginImageContextWithOptions) {
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// Set the scale parameter to your OpenGL ES view's contentScaleFactor
// so that you get a high-resolution snapshot when its value is greater than 1.0
CGFloat scale = eaglview.contentScaleFactor;
widthInPoints = width / scale;
heightInPoints = height / scale;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(widthInPoints, heightInPoints), NO, scale);
}
else {
// On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
widthInPoints = width;
heightInPoints = height;
UIGraphicsBeginImageContext(CGSizeMake(widthInPoints, heightInPoints));
}
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);
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
[Isgl3dDirector sharedInstance].antiAliasingEnabled = YES;
}
注意：对我来说只是评论glBindRenderbufferOES（GL_RENDERBUFFER_OES，_colorRenderbuffer）;和 在您的情况下，您可以使用Isgl3dGLContext2而不是Isgl3dGLContext1执行这些步骤。