vo_gpu: hwdec_d3d11va: allow zero-copy video decoding

Like the manual says, this is technically undefined behaviour. See:
https://msdn.microsoft.com/en-us/library/windows/desktop/ff476085.aspx

In particular, MSDN says texture arrays created with the BIND_DECODER
flag cannot be used with CreateShaderResourceView, which means they
can't be sampled through SRVs like normal Direct3D textures. However,
some programs (Google Chrome included) do this anyway for performance
and power-usage reasons, and it appears to work with most drivers.

Older AMD drivers had a "bug" with zero-copy decoding, but this appears
to have been fixed. See #3255, #3464 and http://crbug.com/623029.

1 files changed, 51 insertions, 13 deletions

diff --git a/video/out/d3d11/ra_d3d11.c b/video/out/d3d11/ra_d3d11.c
index 394f99c70b..3037966f23 100644
--- a/video/out/d3d11/ra_d3d11.c
+++ b/video/out/d3d11/ra_d3d11.c
@@ -75,6 +75,7 @@ struct d3d_tex {
     ID3D11Texture1D *tex1d;
     ID3D11Texture2D *tex2d;
     ID3D11Texture3D *tex3d;
+    int array_slice;
 
     ID3D11ShaderResourceView *srv;
     ID3D11RenderTargetView *rtv;
@@ -259,14 +260,29 @@ static bool tex_init(struct ra *ra, struct ra_tex *tex)
         };
         switch (params->dimensions) {
         case 1:
-            srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1D;
-            srvdesc.Texture1D.MipLevels = 1;
+            if (tex_p->array_slice >= 0) {
+                srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1DARRAY;
+                srvdesc.Texture1DArray.MipLevels = 1;
+                srvdesc.Texture1DArray.FirstArraySlice = tex_p->array_slice;
+                srvdesc.Texture1DArray.ArraySize = 1;
+            } else {
+                srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1D;
+                srvdesc.Texture1D.MipLevels = 1;
+            }
             break;
         case 2:
-            srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
-            srvdesc.Texture2D.MipLevels = 1;
+            if (tex_p->array_slice >= 0) {
+                srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2DARRAY;
+                srvdesc.Texture2DArray.MipLevels = 1;
+                srvdesc.Texture2DArray.FirstArraySlice = tex_p->array_slice;
+                srvdesc.Texture2DArray.ArraySize = 1;
+            } else {
+                srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
+                srvdesc.Texture2D.MipLevels = 1;
+            }
             break;
         case 3:
+            // D3D11 does not have Texture3D arrays
             srvdesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE3D;
             srvdesc.Texture3D.MipLevels = 1;
             break;
@@ -442,6 +458,8 @@ static struct ra_tex *tex_create(struct ra *ra,
         abort();
     }
 
+    tex_p->array_slice = -1;
+
     if (!tex_init(ra, tex))
         goto error;
 
@@ -478,10 +496,18 @@ struct ra_tex *ra_d3d11_wrap_tex(struct ra *ra, ID3D11Resource *res)
 
         D3D11_TEXTURE2D_DESC desc2d;
         ID3D11Texture2D_GetDesc(tex_p->tex2d, &desc2d);
-        if (desc2d.MipLevels != 1 || desc2d.ArraySize != 1)
+        if (desc2d.MipLevels != 1) {
+            MP_ERR(ra, "Mipmapped textures not supported for wrapping\n");
             goto error;
-        if (desc2d.SampleDesc.Count != 1)
+        }
+        if (desc2d.ArraySize != 1) {
+            MP_ERR(ra, "Texture arrays not supported for wrapping\n");
+            goto error;
+        }
+        if (desc2d.SampleDesc.Count != 1) {
+            MP_ERR(ra, "Multisampled textures not supported for wrapping\n");
             goto error;
+        }
 
         params->dimensions = 2;
         params->w = desc2d.Width;
@@ -522,6 +548,8 @@ struct ra_tex *ra_d3d11_wrap_tex(struct ra *ra, ID3D11Resource *res)
         goto error;
     }
 
+    tex_p->array_slice = -1;
+
     if (!tex_init(ra, tex))
         goto error;
 
@@ -532,7 +560,7 @@ error:
 }
 
 struct ra_tex *ra_d3d11_wrap_tex_video(struct ra *ra, ID3D11Texture2D *res,
-                                       int w, int h,
+                                       int w, int h, int array_slice,
                                        const struct ra_format *fmt)
 {
     struct ra_tex *tex = talloc_zero(NULL, struct ra_tex);
@@ -559,6 +587,12 @@ struct ra_tex *ra_d3d11_wrap_tex_video(struct ra *ra, ID3D11Texture2D *res,
     // fmt can be different to the texture format for planar video textures
     params->format = fmt;
 
+    if (desc2d.ArraySize > 1) {
+        tex_p->array_slice = array_slice;
+    } else {
+        tex_p->array_slice = -1;
+    }
+
     if (!tex_init(ra, tex))
         goto error;
 
@@ -611,12 +645,14 @@ static bool tex_upload(struct ra *ra, const struct ra_tex_upload_params *params)
         }
     }
 
+    int subresource = tex_p->array_slice >= 0 ? tex_p->array_slice : 0;
     if (p->ctx1) {
-        ID3D11DeviceContext1_UpdateSubresource1(p->ctx1, tex_p->res, 0, rc,
-            src, stride, pitch, invalidate ? D3D11_COPY_DISCARD : 0);
+        ID3D11DeviceContext1_UpdateSubresource1(p->ctx1, tex_p->res,
+            subresource, rc, src, stride, pitch,
+            invalidate ? D3D11_COPY_DISCARD : 0);
     } else {
-        ID3D11DeviceContext_UpdateSubresource(p->ctx, tex_p->res, 0, rc,
-            src, stride, pitch);
+        ID3D11DeviceContext_UpdateSubresource(p->ctx, tex_p->res, subresource,
+            rc, src, stride, pitch);
     }
 
     return true;
@@ -1174,8 +1210,10 @@ static void blit(struct ra *ra, struct ra_tex *dst, struct ra_tex *src,
     {
         blit_rpass(ra, dst, src, &dst_rc, &src_rc);
     } else {
-        ID3D11DeviceContext_CopySubresourceRegion(p->ctx, dst_p->res, 0,
-            dst_rc.x0, dst_rc.y0, 0, src_p->res, 0, (&(D3D11_BOX) {
+        int dst_sr = dst_p->array_slice >= 0 ? dst_p->array_slice : 0;
+        int src_sr = src_p->array_slice >= 0 ? src_p->array_slice : 0;
+        ID3D11DeviceContext_CopySubresourceRegion(p->ctx, dst_p->res, dst_sr,
+            dst_rc.x0, dst_rc.y0, 0, src_p->res, src_sr, (&(D3D11_BOX) {
                 .left = src_rc.x0,
                 .top = src_rc.y0,
                 .front = 0,