How to Pass Struct by Value?
Jorn Vernee
jorn.vernee at oracle.com
Fri Oct 2 12:19:01 UTC 2020
Hi Michael,
I'm not sure what value you are printing there, since you don't show the
code.
Presumably the ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart
will fill in the 'ptr' field of the D3D12_CPU_DESCRIPTOR_HANDLE you pass
it a pointer to, which is then used by
ID3D12Device_CreateRenderTargetView. So, you could verify that the 'ptr'
field is actually being set when calling
ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart.
Jorn
On 02/10/2020 08:12, Michael Ennen wrote:
> One thing I noticed is that when I create pRtvHandle and print it, I
> get an address like so:
>
> pRtvHandlePtr: MemoryAddress{ base: null offset=0x1c655a6526f }
>
> The ptr struct member also seems to correspond to this number
>
> pRtvHandlePtr: 1951352115823 (converting to hex it is 0x1c655a6526f).
>
> But looking at the DirectX 12 debug errors I see:
>
> [17008] D3D12 ERROR: ID3D12Device::CreateRenderTargetView: Specified
> CPU descriptor handle ptr=0x000001C6D33B6210 does not refer to a
> location in a descriptor heap. [ EXECUTION ERROR #646:
> INVALID_DESCRIPTOR_HANDLE]
>
> And thus I am not sure where it is getting that address from...maybe
> it's the address of the pointer itself and not the ptr struct member?
>
> But even so trying to do:
>
> ID3D12Device_CreateRenderTargetView.invokeExact(pDevice.address(),
> pSurface0.address(), MemoryAddress.NULL,
> MemoryAddress.ofLong(pRtvHandlePtr));
>
> yields an EXCEPTION_ACCESS_VIOLATION so I don't think that's right,
> either.
>
> On Wed, Sep 30, 2020 at 12:40 PM Michael Ennen <mike.ennen at gmail.com
> <mailto:mike.ennen at gmail.com>> wrote:
>
> Sorry, that should have been:
>
> var pRtvHandle = D3D12_CPU_DESCRIPTOR_HANDLE.allocate(scope);
> MethodHandle
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart =
> getInstance().downcallHandle(
> getCPUDescriptorHandleForHeapStartAddr,
> MethodType.methodType(void.class, MemoryAddress.class,
> MemoryAddress.class),
> FunctionDescriptor.ofVoid(C_POINTER, C_POINTER));
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart.invokeExact(
> pHeapDescriptor.address(), pRtvHandle.address());
> MethodHandle ID3D12Device_CreateRenderTargetView =
> getInstance().downcallHandle(
> createRenderTargetViewAddr,
> MethodType.methodType(void.class, MemoryAddress.class,
> MemoryAddress.class, MemoryAddress.class, MemorySegment.class),
> FunctionDescriptor.ofVoid(C_POINTER, C_POINTER, C_POINTER,
> D3D12_CPU_DESCRIPTOR_HANDLE.$LAYOUT()));
> ID3D12Device_CreateRenderTargetView.invokeExact(pDevice.address(),
> pSurface0.address(), MemoryAddress.NULL, pRtvHandle);
>
> On Wed, Sep 30, 2020 at 12:38 PM Michael Ennen
> <mike.ennen at gmail.com <mailto:mike.ennen at gmail.com>> wrote:
>
> I tried using your example and adapting it to the following:
>
> var pRtvHandle = D3D12_CPU_DESCRIPTOR_HANDLE.allocate(scope);
> MethodHandle
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart =
> getInstance().downcallHandle(
> getCPUDescriptorHandleForHeapStartAddr,
> MethodType.methodType(void.class, MemoryAddress.class,
> MemorySegment.class),
> FunctionDescriptor.ofVoid(C_POINTER, C_POINTER));
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart.invokeExact(
> pHeapDescriptor.address(), pRtvHandle.address());
> MethodHandle ID3D12Device_CreateRenderTargetView =
> getInstance().downcallHandle(
> createRenderTargetViewAddr,
> MethodType.methodType(void.class, MemoryAddress.class,
> MemoryAddress.class, MemoryAddress.class, MemorySegment.class),
> FunctionDescriptor.ofVoid(C_POINTER, C_POINTER, C_POINTER,
> D3D12_CPU_DESCRIPTOR_HANDLE.$LAYOUT()));
> ID3D12Device_CreateRenderTargetView.invokeExact(pDevice.address(),
> pSurface0.address(), MemoryAddress.NULL, pRtvHandle);
>
> But no dice.
>
>
> On Wed, Sep 30, 2020 at 11:46 AM Michael Ennen
> <mike.ennen at gmail.com <mailto:mike.ennen at gmail.com>> wrote:
>
> See also:
>
> https://github.com/wolfgangfengel/graphicsdemoskeleton/blob/ba11402b6027ea14322bc430a23f2aadf3c0b11c/DirectX%2012/01_Skeleton/Window.c#L263
> <https://urldefense.com/v3/__https://github.com/wolfgangfengel/graphicsdemoskeleton/blob/ba11402b6027ea14322bc430a23f2aadf3c0b11c/DirectX*2012/01_Skeleton/Window.c*L263__;JSM!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmgm4BTXB$>
>
> On Wed, Sep 30, 2020 at 11:45 AM Michael Ennen
> <mike.ennen at gmail.com <mailto:mike.ennen at gmail.com>> wrote:
>
> Ah yes I should have mentioned that this is actually
> an error with the unsupported DirectX 12 C API.
>
> See the following:
>
> // Even though
> GetCPUDescriptorHandleForHeapStart is documented as
> taking no arguments (except for the
> // this pointer), to use from C code it
> needs to take an additional rtvHandle argument, see,
> for example:
> //
> https://joshstaiger.org/notes/C-Language-Problems-in-Direct3D-12-GetCPUDescriptorHandleForHeapStart.html
> <https://urldefense.com/v3/__https://joshstaiger.org/notes/C-Language-Problems-in-Direct3D-12-GetCPUDescriptorHandleForHeapStart.html__;!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmgVwkGCK$>
> //
> https://github.com/curldivergence/dx12bindings/blob/841974943b7fbbd146d5372e9b496a9d72daf771/build.rs#L33
> <https://urldefense.com/v3/__https://github.com/curldivergence/dx12bindings/blob/841974943b7fbbd146d5372e9b496a9d72daf771/build.rs*L33__;Iw!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmnHkpAW0$>
>
> On Wed, Sep 30, 2020 at 2:55 AM Jorn Vernee
> <jorn.vernee at oracle.com
> <mailto:jorn.vernee at oracle.com>> wrote:
>
> Once again formatting is getting messed up.
>
> Uploaded a file here:
> http://cr.openjdk.java.net/~jvernee/ec.txt
>
> Jorn
>
> On 30/09/2020 11:47, Jorn Vernee wrote:
> > Hi Micheal,
> >
> > When I look at the d3d12.h header, I only find
> this declaration of
> > GetCPUDescriptorHandleForHeapStart:
> >
> > D3D12_CPU_DESCRIPTOR_HANDLE (
> STDMETHODCALLTYPE
> > *GetCPUDescriptorHandleForHeapStart )(
> > ID3D12DescriptorHeap * This);
> >
> > Which is in ID3D12DescriptorHeapVtbl.
> >
> > The return type being defined as:
> >
> > typedef struct D3D12_CPU_DESCRIPTOR_HANDLE
> > {
> > SIZE_T ptr;
> > } D3D12_CPU_DESCRIPTOR_HANDLE;
> >
> > I'd expect this to be linked and invoked as:
> >
> > MemorySegment heapDescriptorVtbl =
> >
> asSegment(ID3D12DescriptorHeap.lpVtbl$get(pHeapDescriptor),
>
> > ID3D12DescriptorHeapVtbl.$LAYOUT()); MemoryAddress
> > getCPUDescriptorHandleForHeapStartAddr =
> >
> ID3D12DescriptorHeapVtbl.GetCPUDescriptorHandleForHeapStart$get(heapDescriptorVtbl);
>
> > MethodHandle
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart
> =
> >
> getInstance().downcallHandle(getCPUDescriptorHandleForHeapStartAddr,
>
> > MethodType.methodType(MemorySegment.class,
> MemoryAddress.class),
> >
> FunctionDescriptor.of(D3D12_CPU_DESCRIPTOR_HANDLE.$LAYOUT(),
>
> > C_POINTER)); MemorySegment handle = (MemorySegment)
> >
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart.invokeExact(pHeapDescriptor.address());
>
> > // ^^^ don't forget to close this after using
> >
> > The linker will take care of handling all the
> ABI details.
> >
> > HTH,
> > Jorn
> >
> > On 30/09/2020 08:36, Michael Ennen wrote:
> >> I am messing around with DirectX 12 more and I
> am getting stuck on
> >> how to
> >> call the "GetCPUDescriptorHandleForHeapStart "
> method. It must take a
> >> struct by-value and not as a pointer reference.
> >>
> https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12descriptorheap-getcpudescriptorhandleforheapstart
> <https://urldefense.com/v3/__https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12descriptorheap-getcpudescriptorhandleforheapstart__;!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmoVq3N9K$>
>
> >>
> >>
> >> There seems to be a bit of an issue with that
> method as I see some
> >> Github
> >> issues talking about it's weird ABI, but I
> don't think I am hitting that
> >> issue (see
> https://github.com/halide/Halide/issues/5156
> <https://urldefense.com/v3/__https://github.com/halide/Halide/issues/5156__;!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmqVYKSkY$>
> for example).
> >>
> >> I have the following:
> >>
> >> MemorySegment heapDescriptorVtbl =
> >>
> asSegment(ID3D12DescriptorHeap.lpVtbl$get(pHeapDescriptor),
> >> ID3D12DescriptorHeapVtbl.$LAYOUT());
> >> MemoryAddress
> getCPUDescriptorHandleForHeapStartAddr =
> >>
> ID3D12DescriptorHeapVtbl.GetCPUDescriptorHandleForHeapStart$get(heapDescriptorVtbl);
>
> >>
> >> var pRtvHandle =
> D3D12_CPU_DESCRIPTOR_HANDLE.allocate(scope);
> >> MethodHandle
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart
> =
> >>
> getInstance().downcallHandle(getCPUDescriptorHandleForHeapStartAddr,
> >> MethodType.methodType(void.class,
> MemoryAddress.class,
> >> MemoryAddress.class),
> >> FunctionDescriptor.ofVoid(C_POINTER, C_POINTER));
> >>
> ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart.invokeExact(
> >> pHeapDescriptor.address(), pRtvHandle.address());
> >>
> >> But it is not right as I am passing in
> D3D12_CPU_DESCRIPTOR_HANDLE as a
> >> pointer.
> >>
> >> I tried exploring the Panama API and looking at
> tests but just didn't
> >> find
> >> what I was looking for (how to pass a struct by
> value, if that's
> >> possible
> >> with the ABI semantics).
> >>
> >> My current work is here:
> >>
> >> https://github.com/brcolow/java-dx12/
> <https://urldefense.com/v3/__https://github.com/brcolow/java-dx12/__;!!GqivPVa7Brio!I6BvzIBgWMA2lOJmtL2_8SkxW-f6kS61xDEp2QD_ymKDSTMczKYyQ9JYmp0p5LUD$>
> >>
> >> Thanks very much.
>
>
>
> --
> Michael Ennen
>
>
>
> --
> Michael Ennen
>
>
>
> --
> Michael Ennen
>
>
>
> --
> Michael Ennen
>
>
>
> --
> Michael Ennen
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