D3D11: Fix Integer Texture Cube mip mapping.

src/compiler/translator/OutputHLSL.cpp

@@ -904,6 +904,14 @@ void OutputHLSL::header(const BuiltInFunctionEmulator *builtInFunctionEmulator)
 
                 out << "    t.x = (u * 0.5f / m) + 0.5f;\n";
                 out << "    t.y = (v * 0.5f / m) + 0.5f;\n";
+
+                // Mip level computation.
+                out << "    float2 tSized = float2(t.x * width, t.y * height);\n"
+                       "    float2 dx = ddx(tSized);\n"
+                       "    float2 dy = ddy(tSized);\n"
+                       "    float lod = 0.5f * log2(max(dot(dx, dx), dot(dy, dy)));\n"
+                       "    mip = uint(min(max(round(lod), 0), levels - 1));\n"
+                       "    x.GetDimensions(mip, width, height, layers, levels);\n";
             }
             else if (IsIntegerSampler(textureFunction->sampler) &&
                      textureFunction->method != TextureFunction::FETCH)

src/libANGLE/renderer/d3d/d3d11/TextureStorage11.cpp

@@ -2225,7 +2225,7 @@ gl::Error TextureStorage11_Cube::createSRV(int baseLevel, int mipLevels, DXGI_FO
     {
         srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2DARRAY;
         srvDesc.Texture2DArray.MostDetailedMip = mTopLevel + baseLevel;
-        srvDesc.Texture2DArray.MipLevels = 1;
+        srvDesc.Texture2DArray.MipLevels       = mipLevels;
         srvDesc.Texture2DArray.FirstArraySlice = 0;
         srvDesc.Texture2DArray.ArraySize = CUBE_FACE_COUNT;
     }