我知道如何创建MTLBuffer和MTLTexture,但是当这些资源不再需要时,如何释放GPU内存呢?
我知道如何创建MTLBuffer和MTLTexture,但是当这些资源不再需要时,如何释放GPU内存呢?
MTLBuffer
和MTLTexture
是Objective-C对象,因此具有引用计数功能。如果您在Objective-C项目中使用自动引用计数或通过Swift使用Metal,则只需确保不再持有对缓冲区或纹理的引用,即可释放任何相关的硬件资源。
let texture: MTLTexture? = device.newTexture(with: descriptor)
texture = nil // <- resources will be released
当将nil
赋值给texture
时,通过逐步跟踪相关的汇编指令,可以确认这一点,该指令首先引导我们到[MTLDebugTexture dealloc]
.
MetalTools`-[MTLDebugTexture dealloc]:
...
-> 0x100af569e <+34>: call 0x100af87ee ; symbol stub for: objc_msgSendSuper2
0x100af56a3 <+39>: add rsp, 0x10
0x100af56a7 <+43>: pop rbp
0x100af56a8 <+44>: ret
...并通过[MTLToolsObject dealloc]
MetalTools`-[MTLToolsObject dealloc]:
0x100ac6c7a <+0>: push rbp
0x100ac6c7b <+1>: mov rbp, rsp
0x100ac6c7e <+4>: push r14
...
...并通过GeForceMTLDriver实现
GeForceMTLDriver`___lldb_unnamed_symbol1095$$GeForceMTLDriver:
-> 0x7fffd2e57b14 <+0>: push rbp
0x7fffd2e57b15 <+1>: mov rbp, rsp
一路上,通过各种dealloc
方法释放任何资源。
如果您正在使用自动引用计数(ARC),就像接受的答案所说,只需设置为nil。
但是,如果您正在使用手动引用计数(MRC),Metal有两种动态分配的资源(MTLBuffer和MTLTexture),您可以按以下方式释放它们。
id<MTLDevice> m_Device = MTLCreateSystemDefaultDevice();
// allocate Buffer
NSUInteger BufferLength = 100;
id<MTLBuffer> m_Buffer = [m_Device newBufferWithLength:BufferLength options:0];
// allocate Texture
MTLTextureDescriptor *shadowTextureDesc = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat: MTLPixelFormatDepth32Float width: 1024 height: 1024 mipmapped: NO];
id<MTLTexture> m_Texture = [m_Device newTextureWithDescriptor:shadowTextureDesc];
// release Buffer
[m_Buffer setPurgeableState:MTLPurgeableStateEmpty];
[m_Buffer release];
// release Texture
[m_Texture setPurgeableState:MTLPurgeableStateEmpty];
[m_Texture release];
关于setPurgeableState,您可以参考链接(https://developer.apple.com/documentation/metal/mtlresource/1515898-setpurgeablestate)。