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我有一个OpenGL应用程序需要在显示数据前在后台执行一些计算。Objective-C:同步块和GCD
随后,我在做什么是:
prepareData
(电话后台线程)_doLongComputation
(在后台线程调用_transferToGPU
)_transferToGPU
(主线程)
因为我在同一个对象glData
上使用块,所以关键部分不应该'不能同时被多个线程访问,但不幸的是情况并非如此,我不知道为什么。
任何想法?
代码的重要部分是以下:
@property (atomic, retain) NSData *glData;
...snip snip...
- (void) _doLongComputation {
@synchronized (glData) {
// Create a buffer (long operation, done in C++)
unsigned long size;
unsigned char* buffer = createBuffer(&size);
// Create NSData to hold it safely
self.glData = [NSData dataWithBytesNoCopy:buffer length:size freeWhenDone:YES];
}
// Don't wand to deal with locking the OpenGL context,
// so we do all the OpenGL-related stuff in the main queue
dispatch_async (dispatch_get_main_queue(), ^{
[self _transferToGPU];
});
}
- (void) _transferToGPU {
@synchronized (glData) {
...snip snip...
// Transfer buffer to GPU
glBufferData(GL_ARRAY_BUFFER,
glData.length,
glData.bytes,
GL_STATIC_DRAW);
// We're done, so set the buffer to nil
self.glData = nil;
}
}
- (void) prepareData {
[self performSelectorInBackground:@selector(_doLongComputation)];
}
唉,该死的,我确定这很明显!当然,最糟糕的事情发生了,我的对象被释放,所以互斥量是无用的。感谢捕捉;) –