diff --git a/libs/vkd3d/device.c b/libs/vkd3d/device.c
index fd0ca208..65095c2d 100644
--- a/libs/vkd3d/device.c
+++ b/libs/vkd3d/device.c
@@ -136,7 +136,8 @@ static HRESULT vkd3d_create_vk_descriptor_heap_layout(struct d3d12_device *devic
         VK_DESCRIPTOR_TYPE_STORAGE_IMAGE,
     };
 
-    if (device->vk_info.EXT_mutable_descriptor_type && index && index != VKD3D_SET_INDEX_UAV_COUNTER
+    if (device->vk_info.EXT_mutable_descriptor_type
+            && index != VKD3D_SET_INDEX_MUTABLE && index != VKD3D_SET_INDEX_UAV_COUNTER
             && device->vk_descriptor_heap_layouts[index].applicable_heap_type == D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV)
     {
         device->vk_descriptor_heap_layouts[index].vk_set_layout = VK_NULL_HANDLE;
@@ -144,7 +145,7 @@ static HRESULT vkd3d_create_vk_descriptor_heap_layout(struct d3d12_device *devic
     }
 
     binding.binding = 0;
-    binding.descriptorType = (device->vk_info.EXT_mutable_descriptor_type && !index)
+    binding.descriptorType = (device->vk_info.EXT_mutable_descriptor_type && index == VKD3D_SET_INDEX_MUTABLE)
             ? VK_DESCRIPTOR_TYPE_MUTABLE_EXT : device->vk_descriptor_heap_layouts[index].type;
     binding.descriptorCount = device->vk_descriptor_heap_layouts[index].count;
     binding.stageFlags = VK_SHADER_STAGE_ALL;
@@ -200,14 +201,20 @@ static HRESULT vkd3d_vk_descriptor_heap_layouts_init(struct d3d12_device *device
 {
     static const struct vkd3d_vk_descriptor_heap_layout vk_descriptor_heap_layouts[VKD3D_SET_INDEX_COUNT] =
     {
-        {VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
-        {VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
-        {VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, false, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
-        {VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
-        {VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, false, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
-        {VK_DESCRIPTOR_TYPE_SAMPLER, false, D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER},
-        /* UAV counters */
-        {VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_UNIFORM_BUFFER] =
+                {VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_UNIFORM_TEXEL_BUFFER] =
+                {VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_SAMPLED_IMAGE] =
+                {VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, false, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_STORAGE_TEXEL_BUFFER] =
+                {VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_STORAGE_IMAGE] =
+                {VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, false, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
+        [VKD3D_SET_INDEX_SAMPLER] =
+                {VK_DESCRIPTOR_TYPE_SAMPLER, false, D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER},
+        [VKD3D_SET_INDEX_UAV_COUNTER] =
+                {VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, true, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV},
     };
     const struct vkd3d_device_descriptor_limits *limits = &device->vk_info.descriptor_limits;
     enum vkd3d_vk_descriptor_set_index set;
diff --git a/libs/vkd3d/resource.c b/libs/vkd3d/resource.c
index 6d6820d3..1f7d90eb 100644
--- a/libs/vkd3d/resource.c
+++ b/libs/vkd3d/resource.c
@@ -2498,7 +2498,7 @@ static void d3d12_desc_write_vk_heap_null_descriptor(struct d3d12_descriptor_hea
     enum vkd3d_vk_descriptor_set_index set, end;
     unsigned int i = writes->count;
 
-    end = device->vk_info.EXT_mutable_descriptor_type ? VKD3D_SET_INDEX_UNIFORM_BUFFER
+    end = device->vk_info.EXT_mutable_descriptor_type ? VKD3D_SET_INDEX_MUTABLE
             : VKD3D_SET_INDEX_STORAGE_IMAGE;
     /* Binding a shader with the wrong null descriptor type works in Windows.
      * To support that here we must write one to all applicable Vulkan sets. */
@@ -4250,7 +4250,8 @@ static HRESULT d3d12_descriptor_heap_create_descriptor_pool(struct d3d12_descrip
         if (device->vk_descriptor_heap_layouts[set].applicable_heap_type == desc->Type
                 && device->vk_descriptor_heap_layouts[set].vk_set_layout)
         {
-            pool_sizes[pool_desc.poolSizeCount].type = (device->vk_info.EXT_mutable_descriptor_type && !set)
+            pool_sizes[pool_desc.poolSizeCount].type =
+                    (device->vk_info.EXT_mutable_descriptor_type && set == VKD3D_SET_INDEX_MUTABLE)
                     ? VK_DESCRIPTOR_TYPE_MUTABLE_EXT : device->vk_descriptor_heap_layouts[set].type;
             pool_sizes[pool_desc.poolSizeCount++].descriptorCount = desc->NumDescriptors;
         }
@@ -4280,11 +4281,12 @@ static HRESULT d3d12_descriptor_heap_create_descriptor_set(struct d3d12_descript
 
     if (!device->vk_descriptor_heap_layouts[set].vk_set_layout)
     {
-        /* Set 0 uses mutable descriptors, and this set is unused. */
-        if (!descriptor_heap->vk_descriptor_sets[0].vk_set
-                && FAILED(hr = d3d12_descriptor_heap_create_descriptor_set(descriptor_heap, device, 0)))
+        /* Mutable descriptors are in use, and this set is unused. */
+        if (!descriptor_heap->vk_descriptor_sets[VKD3D_SET_INDEX_MUTABLE].vk_set
+                && FAILED(hr = d3d12_descriptor_heap_create_descriptor_set(descriptor_heap,
+                device, VKD3D_SET_INDEX_MUTABLE)))
             return hr;
-        descriptor_set->vk_set = descriptor_heap->vk_descriptor_sets[0].vk_set;
+        descriptor_set->vk_set = descriptor_heap->vk_descriptor_sets[VKD3D_SET_INDEX_MUTABLE].vk_set;
         descriptor_set->vk_type = device->vk_descriptor_heap_layouts[set].type;
         return S_OK;
     }
diff --git a/libs/vkd3d/state.c b/libs/vkd3d/state.c
index 8e5ec70a..bff36990 100644
--- a/libs/vkd3d/state.c
+++ b/libs/vkd3d/state.c
@@ -1016,7 +1016,7 @@ static void vkd3d_descriptor_heap_binding_from_descriptor_range(const struct d3d
         }
         else
         {
-            binding->set = 0;
+            binding->set = VKD3D_SET_INDEX_MUTABLE;
             descriptor_set_size = descriptor_limits->sampled_image_max_descriptors;
         }
     }
@@ -1482,22 +1482,22 @@ static unsigned int d3d12_root_signature_copy_descriptor_set_layouts(const struc
         VkDescriptorSetLayout *vk_set_layouts)
 {
     const struct d3d12_device *device = root_signature->device;
+    VkDescriptorSetLayout mutable_layout, vk_set_layout;
     enum vkd3d_vk_descriptor_set_index set;
     unsigned int i;
 
     for (i = 0; i < root_signature->vk_set_count; ++i)
         vk_set_layouts[i] = root_signature->descriptor_set_layouts[i].vk_layout;
 
-    if (device->use_vk_heaps)
-    {
-        VkDescriptorSetLayout mutable_layout = device->vk_descriptor_heap_layouts[0].vk_set_layout;
+    if (!device->use_vk_heaps)
+        return i;
 
-        for (set = 0; set < ARRAY_SIZE(device->vk_descriptor_heap_layouts); ++set)
-        {
-            VkDescriptorSetLayout vk_set_layout = device->vk_descriptor_heap_layouts[set].vk_set_layout;
-            /* All layouts must be valid, so if null, just set it to the mutable one. */
-            vk_set_layouts[i++] = vk_set_layout ? vk_set_layout : mutable_layout;
-        }
+    mutable_layout = device->vk_descriptor_heap_layouts[VKD3D_SET_INDEX_MUTABLE].vk_set_layout;
+    for (set = 0; set < ARRAY_SIZE(device->vk_descriptor_heap_layouts); ++set)
+    {
+        vk_set_layout = device->vk_descriptor_heap_layouts[set].vk_set_layout;
+        /* All layouts must be valid, so if null, just set it to the mutable one. */
+        vk_set_layouts[i++] = vk_set_layout ? vk_set_layout : mutable_layout;
     }
 
     return i;
diff --git a/libs/vkd3d/vkd3d_private.h b/libs/vkd3d/vkd3d_private.h
index 65ace137..412380cf 100644
--- a/libs/vkd3d/vkd3d_private.h
+++ b/libs/vkd3d/vkd3d_private.h
@@ -773,6 +773,7 @@ void d3d12_dsv_desc_create_dsv(struct d3d12_dsv_desc *dsv_desc, struct d3d12_dev
 enum vkd3d_vk_descriptor_set_index
 {
     VKD3D_SET_INDEX_UNIFORM_BUFFER = 0,
+    VKD3D_SET_INDEX_MUTABLE = VKD3D_SET_INDEX_UNIFORM_BUFFER,
     VKD3D_SET_INDEX_UNIFORM_TEXEL_BUFFER = 1,
     VKD3D_SET_INDEX_SAMPLED_IMAGE = 2,
     VKD3D_SET_INDEX_STORAGE_TEXEL_BUFFER = 3,