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Added convenience function vmaGetAllocationMemoryProperties

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Regenerated documentation.
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Adam Sawicki 2021-11-23 13:35:19 +01:00
parent 55553cff34
commit fac8ef44d2
9 changed files with 155 additions and 93 deletions
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@ -138,7 +138,7 @@ Cache flush and invalidate</h1>
<h1><a class="anchor" id="memory_mapping_finding_if_memory_mappable"></a>
Finding out if memory is mappable</h1>
<p >It may happen that your allocation ends up in memory that is <code>HOST_VISIBLE</code> (available for mapping) despite it wasn't explicitly requested. For example, application may work on integrated graphics with unified memory (like Intel) or allocation from video memory might have failed, so the library chose system memory as fallback.</p>
<p >You can detect this case and map such allocation to access its memory on CPU directly, instead of launching a transfer operation. In order to do that: inspect <code>allocInfo.memoryType</code>, call <a class="el" href="vk__mem__alloc_8h.html#a8701444752eb5de4464adb5a2b514bca" title="Given Memory Type Index, returns Property Flags of this memory type.">vmaGetMemoryTypeProperties()</a>, and look for <code>VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT</code> flag in properties of that memory type.</p>
<p >You can detect this case and map such allocation to access its memory on CPU directly, instead of launching a transfer operation. In order to do that: call <a class="el" href="vk__mem__alloc_8h.html#a571e87dd38e552249b56b1b0b982fad1" title="Given an allocation, returns Property Flags of its memory type.">vmaGetAllocationMemoryProperties()</a> and look for <code>VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT</code> flag.</p>
<div class="fragment"><div class="line">VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div>
<div class="line">bufCreateInfo.size = <span class="keyword">sizeof</span>(ConstantBuffer);</div>
<div class="line">bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;</div>
@ -149,11 +149,10 @@ Finding out if memory is mappable</h1>
<div class="line"> </div>
<div class="line">VkBuffer buf;</div>
<div class="line"><a class="code hl_struct" href="struct_vma_allocation.html">VmaAllocation</a> alloc;</div>
<div class="line"><a class="code hl_struct" href="struct_vma_allocation_info.html">VmaAllocationInfo</a> allocInfo;</div>
<div class="line"><a class="code hl_function" href="vk__mem__alloc_8h.html#ac72ee55598617e8eecca384e746bab51">vmaCreateBuffer</a>(allocator, &amp;bufCreateInfo, &amp;allocCreateInfo, &amp;buf, &amp;alloc, &amp;allocInfo);</div>
<div class="line"><a class="code hl_function" href="vk__mem__alloc_8h.html#ac72ee55598617e8eecca384e746bab51">vmaCreateBuffer</a>(allocator, &amp;bufCreateInfo, &amp;allocCreateInfo, &amp;buf, &amp;alloc, <span class="keyword">nullptr</span>);</div>
<div class="line"> </div>
<div class="line">VkMemoryPropertyFlags memFlags;</div>
<div class="line"><a class="code hl_function" href="vk__mem__alloc_8h.html#a8701444752eb5de4464adb5a2b514bca">vmaGetMemoryTypeProperties</a>(allocator, allocInfo.<a class="code hl_variable" href="struct_vma_allocation_info.html#a7f6b0aa58c135e488e6b40a388dad9d5">memoryType</a>, &amp;memFlags);</div>
<div class="line"><a class="code hl_function" href="vk__mem__alloc_8h.html#a571e87dd38e552249b56b1b0b982fad1">vmaGetAllocationMemoryProperties</a>(allocator, alloc, &amp;memFlags);</div>
<div class="line"><span class="keywordflow">if</span>((memFlags &amp; VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)</div>
<div class="line">{</div>
<div class="line"> <span class="comment">// Allocation ended up in mappable memory. You can map it and access it directly.</span></div>
@ -168,8 +167,7 @@ Finding out if memory is mappable</h1>
<div class="line"> <span class="comment">// You need to create CPU-side buffer in VMA_MEMORY_USAGE_CPU_ONLY and make a transfer.</span></div>
<div class="line">}</div>
<div class="ttc" id="astruct_vma_allocation_create_info_html_a7fe8d81a1ad10b2a2faacacee5b15d6d"><div class="ttname"><a href="struct_vma_allocation_create_info.html#a7fe8d81a1ad10b2a2faacacee5b15d6d">VmaAllocationCreateInfo::preferredFlags</a></div><div class="ttdeci">VkMemoryPropertyFlags preferredFlags</div><div class="ttdoc">Flags that preferably should be set in a memory type chosen for an allocation.</div><div class="ttdef"><b>Definition:</b> vk_mem_alloc.h:1010</div></div>
<div class="ttc" id="astruct_vma_allocation_info_html_a7f6b0aa58c135e488e6b40a388dad9d5"><div class="ttname"><a href="struct_vma_allocation_info.html#a7f6b0aa58c135e488e6b40a388dad9d5">VmaAllocationInfo::memoryType</a></div><div class="ttdeci">uint32_t memoryType</div><div class="ttdoc">Memory type index that this allocation was allocated from.</div><div class="ttdef"><b>Definition:</b> vk_mem_alloc.h:1362</div></div>
<div class="ttc" id="avk__mem__alloc_8h_html_a8701444752eb5de4464adb5a2b514bca"><div class="ttname"><a href="vk__mem__alloc_8h.html#a8701444752eb5de4464adb5a2b514bca">vmaGetMemoryTypeProperties</a></div><div class="ttdeci">void vmaGetMemoryTypeProperties(VmaAllocator allocator, uint32_t memoryTypeIndex, VkMemoryPropertyFlags *pFlags)</div><div class="ttdoc">Given Memory Type Index, returns Property Flags of this memory type.</div></div>
<div class="ttc" id="avk__mem__alloc_8h_html_a571e87dd38e552249b56b1b0b982fad1"><div class="ttname"><a href="vk__mem__alloc_8h.html#a571e87dd38e552249b56b1b0b982fad1">vmaGetAllocationMemoryProperties</a></div><div class="ttdeci">void vmaGetAllocationMemoryProperties(VmaAllocator allocator, VmaAllocation allocation, VkMemoryPropertyFlags *pFlags)</div><div class="ttdoc">Given an allocation, returns Property Flags of its memory type.</div></div>
<div class="ttc" id="avk__mem__alloc_8h_html_aa5846affa1e9da3800e3e78fae2305ccac6b5dc1432d88647aa4cd456246eadf7"><div class="ttname"><a href="vk__mem__alloc_8h.html#aa5846affa1e9da3800e3e78fae2305ccac6b5dc1432d88647aa4cd456246eadf7">VMA_MEMORY_USAGE_GPU_ONLY</a></div><div class="ttdeci">@ VMA_MEMORY_USAGE_GPU_ONLY</div><div class="ttdef"><b>Definition:</b> vk_mem_alloc.h:834</div></div>
</div><!-- fragment --><p >You can even use <a class="el" href="vk__mem__alloc_8h.html#ad9889c10c798b040d59c92f257cae597a11da372cc3a82931c5e5d6146cd9dd1f" title="Set this flag to use a memory that will be persistently mapped and retrieve pointer to it.">VMA_ALLOCATION_CREATE_MAPPED_BIT</a> flag while creating allocations that are not necessarily <code>HOST_VISIBLE</code> (e.g. using <a class="el" href="vk__mem__alloc_8h.html#aa5846affa1e9da3800e3e78fae2305ccac6b5dc1432d88647aa4cd456246eadf7">VMA_MEMORY_USAGE_GPU_ONLY</a>). If the allocation ends up in memory type that is <code>HOST_VISIBLE</code>, it will be persistently mapped and you can use it directly. If not, the flag is just ignored. Example:</p>
<div class="fragment"><div class="line">VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div>