[dxvk] Eliminate buffer slice copy when updating buffer descriptors

src/dxvk/dxvk_buffer.h

@@ -68,6 +68,18 @@ namespace dxvk {
       return m_physSlice.resource()->isInUse();
     }
 
+    /**
+     * \brief Retrieves descriptor info
+     * 
+     * \param [in] offset Buffer slice offset
+     * \param [in] length Buffer slice length
+     * \param [in] keepOffset \c false to zero offset
+     * \returns Buffer slice descriptor
+     */
+    DxvkDescriptorInfo getDescriptor(VkDeviceSize offset, VkDeviceSize length, bool keepOffset) const {
+      return m_physSlice.getDescriptor(offset, length, keepOffset);
+    }
+    
     /**
      * \brief Underlying buffer resource
      * 
@@ -248,6 +260,16 @@ namespace dxvk {
       return m_buffer->subSlice(m_offset, m_length);
     }
 
+    /**
+     * \brief Retrieves descriptor info
+     * 
+     * \param [in] keepOffset \c false to zero offset
+     * \returns Buffer slice descriptor
+     */
+    DxvkDescriptorInfo getDescriptor(bool keepOffset) const {
+      return m_buffer->getDescriptor(m_offset, m_length, keepOffset);
+    }
+    
     /**
      * \brief Pointer to mapped memory region
      * 
@@ -258,6 +280,14 @@ namespace dxvk {
       return m_buffer->mapPtr(m_offset + offset);
     }
     
+    /**
+     * \brief Resource pointer
+     * \returns Resource pointer
+     */
+    Rc<DxvkResource> resource() const {
+      return m_buffer->resource();
+    }
+    
     /**
      * \brief Checks whether two slices are equal
      * 

src/dxvk/dxvk_buffer_res.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "dxvk_descriptor.h"
 #include "dxvk_format.h"
 #include "dxvk_memory.h"
 #include "dxvk_resource.h"
@@ -89,6 +90,21 @@ namespace dxvk {
       return m_memory.mapPtr(offset);
     }
 
+    /**
+     * \brief Retrieves descriptor info
+     * 
+     * \param [in] offset Buffer slice offset
+     * \param [in] length Buffer slice length
+     * \returns Buffer slice descriptor
+     */
+    DxvkDescriptorInfo getDescriptor(VkDeviceSize offset, VkDeviceSize length) const {
+      DxvkDescriptorInfo result;
+      result.buffer.buffer = m_handle;
+      result.buffer.offset = offset;
+      result.buffer.range  = length;
+      return result;
+    }
+    
     /**
      * \brief Retrieves a physical buffer slice
      * 
@@ -168,6 +184,19 @@ namespace dxvk {
       return DxvkPhysicalBufferSlice(m_buffer, m_offset + offset, length);
     }
 
+    /**
+     * \brief Retrieves descriptor info
+     * 
+     * \param [in] offset Buffer slice offset
+     * \param [in] length Buffer slice length
+     * \param [in] keepOffset \c false to zero offset
+     * \returns Buffer slice descriptor
+     */
+    DxvkDescriptorInfo getDescriptor(VkDeviceSize offset, VkDeviceSize length, bool keepOffset) const {
+      offset = keepOffset ? m_offset + offset : 0;
+      return m_buffer->getDescriptor(offset, length);
+    }
+    
     /**
      * \brief Map pointer
      * 

src/dxvk/dxvk_context.cpp

@@ -2244,13 +2244,9 @@ namespace dxvk {
         case VK_DESCRIPTOR_TYPE_STORAGE_BUFFER:
           if (res.bufferSlice.defined()) {
             updatePipelineState |= bindMask.setBound(i);
+            m_descInfos[i] = res.bufferSlice.getDescriptor(true);
             
-            auto physicalSlice = res.bufferSlice.physicalSlice();
+            m_cmd->trackResource(res.bufferSlice.resource());
-            m_descInfos[i].buffer.buffer = physicalSlice.handle();
-            m_descInfos[i].buffer.offset = physicalSlice.offset();
-            m_descInfos[i].buffer.range  = physicalSlice.length();
-            
-            m_cmd->trackResource(physicalSlice.resource());
           } else {
             updatePipelineState |= bindMask.setUnbound(i);
             m_descInfos[i].buffer = m_device->dummyBufferDescriptor();
@@ -2260,13 +2256,9 @@ namespace dxvk {
         case VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC:
           if (res.bufferSlice.defined()) {
             updatePipelineState |= bindMask.setBound(i);
+            m_descInfos[i] = res.bufferSlice.getDescriptor(false);
             
-            auto physicalSlice = res.bufferSlice.physicalSlice();
+            m_cmd->trackResource(res.bufferSlice.resource());
-            m_descInfos[i].buffer.buffer = physicalSlice.handle();
-            m_descInfos[i].buffer.offset = 0; /* dynamic */
-            m_descInfos[i].buffer.range  = physicalSlice.length();
-            
-            m_cmd->trackResource(physicalSlice.resource());
           } else {
             updatePipelineState |= bindMask.setUnbound(i);
             m_descInfos[i].buffer = m_device->dummyBufferDescriptor();