More documentation. Especially added new section "Finding out if memory is mappable".

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Adam Sawicki 2018-03-02 13:05:39 +01:00
parent a3e019d476
commit 0c11b12574
6 changed files with 190 additions and 131 deletions

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@ -66,11 +66,13 @@ $(function() {
<div class="title">Custom memory pools </div> </div>
</div><!--header-->
<div class="contents">
<div class="textblock"><p>The library automatically creates and manages default memory pool for each memory type available on the device. A pool contains a number of <code>VkDeviceMemory</code> blocks. You can create custom pool and allocate memory out of it. It can be useful if you want to:</p>
<div class="textblock"><p>A memory pool contains a number of <code>VkDeviceMemory</code> blocks. The library automatically creates and manages default pool for each memory type available on the device. Default memory pool automatically grows in size. Size of allocated blocks is also variable and managed automatically.</p>
<p>You can create custom pool and allocate memory out of it. It can be useful if you want to:</p>
<ul>
<li>Keep certain kind of allocations separate from others.</li>
<li>Enforce particular size of Vulkan memory blocks.</li>
<li>Enforce particular, fixed size of Vulkan memory blocks.</li>
<li>Limit maximum amount of Vulkan memory allocated for that pool.</li>
<li>Reserve minimum or fixed amount of Vulkan memory always preallocated for that pool.</li>
</ul>
<p>To use custom memory pools:</p>
<ol type="1">
@ -79,7 +81,7 @@ $(function() {
<li>When making an allocation, set <a class="el" href="struct_vma_allocation_create_info.html#a6272c0555cfd1fe28bff1afeb6190150" title="Pool that this allocation should be created in. ">VmaAllocationCreateInfo::pool</a> to this handle. You don't need to specify any other parameters of this structure, like usage.</li>
</ol>
<p>Example:</p>
<div class="fragment"><div class="line"><span class="comment">// Create a pool that could have at most 2 blocks, 128 MiB each.</span></div><div class="line"><a class="code" href="struct_vma_pool_create_info.html">VmaPoolCreateInfo</a> poolCreateInfo = {};</div><div class="line">poolCreateInfo.<a class="code" href="struct_vma_pool_create_info.html#a596fa76b685d3f1f688f84a709a5b319">memoryTypeIndex</a> = ...</div><div class="line">poolCreateInfo.blockSize = 128ull * 1024 * 1024;</div><div class="line">poolCreateInfo.<a class="code" href="struct_vma_pool_create_info.html#ae41142f2834fcdc82baa4883c187b75c">maxBlockCount</a> = 2;</div><div class="line"></div><div class="line">VmaPool pool;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#a5c8770ded7c59c8caac6de0c2cb00b50">vmaCreatePool</a>(allocator, &amp;poolCreateInfo, &amp;pool);</div><div class="line"></div><div class="line"><span class="comment">// Allocate a buffer out of it.</span></div><div class="line">VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div><div class="line">bufCreateInfo.size = 1024;</div><div class="line">bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;</div><div class="line"></div><div class="line"><a class="code" href="struct_vma_allocation_create_info.html">VmaAllocationCreateInfo</a> allocCreateInfo = {};</div><div class="line">allocCreateInfo.<a class="code" href="struct_vma_allocation_create_info.html#a6272c0555cfd1fe28bff1afeb6190150">pool</a> = pool;</div><div class="line"></div><div class="line">VkBuffer buf;</div><div class="line">VmaAllocation alloc;</div><div class="line"><a class="code" href="struct_vma_allocation_info.html">VmaAllocationInfo</a> allocInfo;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#ac72ee55598617e8eecca384e746bab51">vmaCreateBuffer</a>(allocator, &amp;bufCreateInfo, &amp;allocCreateInfo, &amp;buf, &amp;alloc, &amp;allocInfo);</div></div><!-- fragment --><p>You have to free all allocations made from this pool before destroying it.</p>
<div class="fragment"><div class="line"><span class="comment">// Create a pool that can have at most 2 blocks, 128 MiB each.</span></div><div class="line"><a class="code" href="struct_vma_pool_create_info.html">VmaPoolCreateInfo</a> poolCreateInfo = {};</div><div class="line">poolCreateInfo.<a class="code" href="struct_vma_pool_create_info.html#a596fa76b685d3f1f688f84a709a5b319">memoryTypeIndex</a> = ...</div><div class="line">poolCreateInfo.blockSize = 128ull * 1024 * 1024;</div><div class="line">poolCreateInfo.<a class="code" href="struct_vma_pool_create_info.html#ae41142f2834fcdc82baa4883c187b75c">maxBlockCount</a> = 2;</div><div class="line"></div><div class="line">VmaPool pool;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#a5c8770ded7c59c8caac6de0c2cb00b50">vmaCreatePool</a>(allocator, &amp;poolCreateInfo, &amp;pool);</div><div class="line"></div><div class="line"><span class="comment">// Allocate a buffer out of it.</span></div><div class="line">VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div><div class="line">bufCreateInfo.size = 1024;</div><div class="line">bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;</div><div class="line"></div><div class="line"><a class="code" href="struct_vma_allocation_create_info.html">VmaAllocationCreateInfo</a> allocCreateInfo = {};</div><div class="line">allocCreateInfo.<a class="code" href="struct_vma_allocation_create_info.html#a6272c0555cfd1fe28bff1afeb6190150">pool</a> = pool;</div><div class="line"></div><div class="line">VkBuffer buf;</div><div class="line">VmaAllocation alloc;</div><div class="line"><a class="code" href="struct_vma_allocation_info.html">VmaAllocationInfo</a> allocInfo;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#ac72ee55598617e8eecca384e746bab51">vmaCreateBuffer</a>(allocator, &amp;bufCreateInfo, &amp;allocCreateInfo, &amp;buf, &amp;alloc, &amp;allocInfo);</div></div><!-- fragment --><p>You have to free all allocations made from this pool before destroying it.</p>
<div class="fragment"><div class="line"><a class="code" href="vk__mem__alloc_8h.html#a0d9f4e4ba5bf9aab1f1c746387753d77">vmaDestroyBuffer</a>(allocator, buf, alloc);</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#a5485779c8f1948238fc4e92232fa65e1">vmaDestroyPool</a>(allocator, pool);</div></div><!-- fragment --><h1><a class="anchor" id="custom_memory_pools_MemTypeIndex"></a>
Choosing memory type index</h1>
<p>When creating a pool, you must explicitly specify memory type index. To find the one suitable for your buffers or images, you can use code similar to the following:</p>