Fixed vmaVirtualFree legal to call with allocation == VK_NULL_HANDLE

Hopefully fixes #230
Fixes in internal validation.
Rebuilt the docs.

docs/html/group__group__virtual.html

@@ -610,7 +610,7 @@ Functions</h2></td></tr>
 </div><div class="memdoc">
 
 <p>Allocates new virtual allocation inside given <a class="el" href="struct_vma_virtual_block.html" title="Handle to a virtual block object that allows to use core allocation algorithm without allocating any ...">VmaVirtualBlock</a>. </p>
-<p >If the allocation fails due to not enough free space available, <code>VK_ERROR_OUT_OF_DEVICE_MEMORY</code> is returned (despite the function doesn't ever allocate actual GPU memory). <code>pAllocation</code> is then set to <code>VK_NULL_HANDLE</code> AND <code>pOffset</code>, if not null, it set to <code>UINT64_MAX</code>.</p>
+<p >If the allocation fails due to not enough free space available, <code>VK_ERROR_OUT_OF_DEVICE_MEMORY</code> is returned (despite the function doesn't ever allocate actual GPU memory). <code>pAllocation</code> is then set to <code>VK_NULL_HANDLE</code> and <code>pOffset</code>, if not null, it set to <code>UINT64_MAX</code>.</p>
 <dl class="params"><dt>Parameters</dt><dd>
   <table class="params">
     <tr><td class="paramdir"></td><td class="paramname">virtualBlock</td><td>Virtual block </td></tr>
@@ -650,6 +650,7 @@ Functions</h2></td></tr>
 </div><div class="memdoc">
 
 <p>Frees virtual allocation inside given <a class="el" href="struct_vma_virtual_block.html" title="Handle to a virtual block object that allows to use core allocation algorithm without allocating any ...">VmaVirtualBlock</a>. </p>
+<p >It is correct to call this function with <code>allocation == VK_NULL_HANDLE</code> - it does nothing. </p>
 
 </div>
 </div>

docs/html/struct_vma_virtual_allocation.html

@@ -73,6 +73,7 @@ $(function() {
 <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
 <div class="textblock"><p >Represents single memory allocation done inside <a class="el" href="struct_vma_virtual_block.html" title="Handle to a virtual block object that allows to use core allocation algorithm without allocating any ...">VmaVirtualBlock</a>. </p>
 <p >Use it as a unique identifier to virtual allocation within the single block.</p>
+<p >Use value <code>VK_NULL_HANDLE</code> to represent a null/invalid allocation. </p>
 </div><hr/>The documentation for this struct was generated from the following file:<ul>
 <li>D:/PROJECTS/Vulkan Memory Allocator/REPO/include/<a class="el" href="vk__mem__alloc_8h.html">vk_mem_alloc.h</a></li>
 </ul>

include/vk_mem_alloc.h

@@ -833,6 +833,8 @@ VK_DEFINE_HANDLE(VmaDefragmentationContext)
 \brief Represents single memory allocation done inside VmaVirtualBlock.
 
 Use it as a unique identifier to virtual allocation within the single block.
+
+Use value `VK_NULL_HANDLE` to represent a null/invalid allocation.
 */
 VK_DEFINE_NON_DISPATCHABLE_HANDLE(VmaVirtualAllocation);
 
@@ -2382,6 +2384,8 @@ VMA_CALL_PRE VkResult VMA_CALL_POST vmaVirtualAllocate(
     VkDeviceSize* VMA_NULLABLE pOffset);
 
 /** \brief Frees virtual allocation inside given #VmaVirtualBlock.
+
+It is correct to call this function with `allocation == VK_NULL_HANDLE` - it does nothing.
 */
 VMA_CALL_PRE void VMA_CALL_POST vmaVirtualFree(
     VmaVirtualBlock VMA_NOT_NULL virtualBlock,
@@ -6572,7 +6576,7 @@ bool VmaBlockMetadata_Generic::Validate() const
         {
             if (!IsVirtual())
             {
-                VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == subAlloc.offset);
+                VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == subAlloc.offset + 1);
                 VMA_VALIDATE(alloc->GetSize() == subAlloc.size);
             }
 
@@ -7435,7 +7439,7 @@ bool VmaBlockMetadata_Linear::Validate() const
             {
                 if (!IsVirtual())
                 {
-                    VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset);
+                    VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset + 1);
                     VMA_VALIDATE(alloc->GetSize() == suballoc.size);
                 }
                 sumUsedSize += suballoc.size;
@@ -7477,7 +7481,7 @@ bool VmaBlockMetadata_Linear::Validate() const
         {
             if (!IsVirtual())
             {
-                VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset);
+                VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset + 1);
                 VMA_VALIDATE(alloc->GetSize() == suballoc.size);
             }
             sumUsedSize += suballoc.size;
@@ -7511,7 +7515,7 @@ bool VmaBlockMetadata_Linear::Validate() const
             {
                 if (!IsVirtual())
                 {
-                    VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset);
+                    VMA_VALIDATE((VkDeviceSize)alloc->GetAllocHandle() == suballoc.offset + 1);
                     VMA_VALIDATE(alloc->GetSize() == suballoc.size);
                 }
                 sumUsedSize += suballoc.size;
@@ -17847,7 +17851,7 @@ VMA_CALL_PRE VkResult VMA_CALL_POST vmaVirtualAllocate(VmaVirtualBlock VMA_NOT_N
 
 VMA_CALL_PRE void VMA_CALL_POST vmaVirtualFree(VmaVirtualBlock VMA_NOT_NULL virtualBlock, VmaVirtualAllocation allocation)
 {
-    if(virtualBlock != VMA_NULL)
+    if(allocation != VK_NULL_HANDLE)
     {
         VMA_ASSERT(virtualBlock != VK_NULL_HANDLE);
         VMA_DEBUG_LOG("vmaVirtualFree");

src/Tests.cpp

@@ -2799,6 +2799,9 @@ static void TestVirtualBlocks()
 
     vmaVirtualFree(block, allocation0);
 
+    // # Test free of null allocation.
+    vmaVirtualFree(block, VK_NULL_HANDLE);
+
     // # Test alignment
 
     {