Re: [PATCH 1/2] d2d1: Implement ID2D1Bitmap1::Map().

[Dmitry Timoshkov]

Nikolay Sivov  wrote:
> On 5/12/22 16:23, Dmitry Timoshkov wrote:
> > static HRESULT STDMETHODCALLTYPE d2d_bitmap_Map(ID2D1Bitmap1 *iface, D2D1_MAP_OPTIONS options,
> >           D2D1_MAPPED_RECT *mapped_rect)
> >   {
> > - FIXME("iface %p, options %#x, mapped_rect %p stub!\n", iface, options, mapped_rect);
> > - struct d2d_bitmap *bitmap = impl_from_ID2D1Bitmap1(iface);
> > - ID3D11Device *device;
> > - ID3D11DeviceContext *context;
> > - D3D11_TEXTURE2D_DESC texture_desc;
> > - ID3D11Texture2D *staging_texture;
> > - D3D11_MAPPED_SUBRESOURCE mapped_subresource;
> > - HRESULT hr;
> > - return E_NOTIMPL;
> > - TRACE("iface %p, options %#x, mapped_rect %p.\n", iface, options, mapped_rect);
> > -
> > - ID3D11Resource_GetDevice(bitmap->resource, &device);
> > - ID3D11Device_GetImmediateContext(device, &context);
> > - ID3D11Texture2D_GetDesc((ID3D11Texture2D *)bitmap->resource, &texture_desc);
> > -
> > - texture_desc.Usage = D3D11_USAGE_STAGING;
> > - texture_desc.BindFlags = 0;
> > - texture_desc.CPUAccessFlags = d3d11_cpu_access_from_d2d1_map_options(options);
> > - ID3D11Device_CreateTexture2D(device, &texture_desc, NULL, &staging_texture);
> > - ID3D11DeviceContext_CopyResource(context, (ID3D11Resource *)staging_texture, bitmap->resource);
> > - if (SUCCEEDED(hr = ID3D11DeviceContext_Map(context, (ID3D11Resource *)staging_texture, 0,
> > -
> >        d3d11_map_from_d2d1_map_options(options), 0, &mapped_subresource)))
> > - {
> > -
> >    mapped_rect->pitch = mapped_subresource.RowPitch;
> > -
> >    mapped_rect->bits = mapped_subresource.pData;
> > -
> >    bitmap->staging_resource = (ID3D11Resource *)staging_texture;
> > - }
> > - else
> > - {
> > -
> >    WARN("Failed to map resource, hr %#lx.\n", hr);
> > -
> >    ID3D11Texture2D_Release(staging_texture);
> > - }
> > -
> > - ID3D11DeviceContext_Release(context);
> > - ID3D11Device_Release(device);
> > -
> > - return hr;
> > }
>
> According to docs, Map() only works for D2D1_BITMAP_OPTIONS_CPU_READ, 
> that potentially simplifies things.

Thanks for the review. I guess that you suggest to drop the from_d2d1_map_options()
helpers and always use READ access, is that correct, or there are other things to
get into account for simplification?
> Also Unmap() in patch 2 will not 
> write anything back.

Should it? I don't see that mentioned in MSDN, and implying that only READ access
is supposed to be supported by ::Map() it means that bitmap memory can't be modified
by user.