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@ -84,8 +84,13 @@ $(function() {
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<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, &poolCreateInfo, &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, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);</div></div><!-- fragment --><p>You have to free all allocations made from this pool before destroying it.</p>
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<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>
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Choosing memory type index</h1>
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<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>
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<div class="fragment"><div class="line">VkBufferCreateInfo dummyBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div><div class="line">dummyBufCreateInfo.size = 1024; <span class="comment">// Whatever.</span></div><div class="line">dummyBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; <span class="comment">// Change if needed.</span></div><div class="line"></div><div class="line">VkBuffer dummyBuf;</div><div class="line">vkCreateBuffer(device, &dummyBufCreateInfo, <span class="keyword">nullptr</span>, &dummyBuf);</div><div class="line"></div><div class="line">VkMemoryRequirements memReq;</div><div class="line">vkGetBufferMemoryRequirements(device, dummyBuf, &memReq);</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#accb8b06b1f677d858cb9af20705fa910">usage</a> = <a class="code" href="vk__mem__alloc_8h.html#aa5846affa1e9da3800e3e78fae2305ccac6b5dc1432d88647aa4cd456246eadf7">VMA_MEMORY_USAGE_GPU_ONLY</a>; <span class="comment">// Change if needed.</span></div><div class="line"></div><div class="line">uint32_t memTypeIndex;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#aef15a94b58fbcb0fe706d5720e84a74a">vmaFindMemoryTypeIndex</a>(allocator, memReq.memoryTypeBits, &allocCreateInfo, &memTypeIndex);</div><div class="line"></div><div class="line">vkDestroyBuffer(device, dummyBuf, <span class="keyword">nullptr</span>);</div><div class="line"></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> = memTypeIndex;</div><div class="line"><span class="comment">// ...</span></div></div><!-- fragment --><p>Dummy buffer is needed to query driver for <code>memReq.memoryTypeBits</code>. Memory is never allocated for this buffer. You should fill structures <code>dummyBufCreateInfo</code> and <code>allocCreateInfo</code> with the same parameters as you are going to use for buffers created in your pool. </p>
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<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 helper functions <a class="el" href="vk__mem__alloc_8h.html#ae790ab9ffaf7667fb8f62523e6897888" title="Helps to find memoryTypeIndex, given VkBufferCreateInfo and VmaAllocationCreateInfo. ">vmaFindMemoryTypeIndexForBufferInfo()</a>, <a class="el" href="vk__mem__alloc_8h.html#a088da83d8eaf3ce9056d9ea0b981d472" title="Helps to find memoryTypeIndex, given VkImageCreateInfo and VmaAllocationCreateInfo. ">vmaFindMemoryTypeIndexForImageInfo()</a>. You need to provide structures with example parameters of buffers or images that you are going to create in that pool.</p>
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<div class="fragment"><div class="line">VkBufferCreateInfo exampleBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };</div><div class="line">exampleBufCreateInfo.size = 1024; <span class="comment">// Whatever.</span></div><div class="line">exampleBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; <span class="comment">// Change if needed.</span></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#accb8b06b1f677d858cb9af20705fa910">usage</a> = <a class="code" href="vk__mem__alloc_8h.html#aa5846affa1e9da3800e3e78fae2305ccac6b5dc1432d88647aa4cd456246eadf7">VMA_MEMORY_USAGE_GPU_ONLY</a>; <span class="comment">// Change if needed.</span></div><div class="line"></div><div class="line">uint32_t memTypeIndex;</div><div class="line"><a class="code" href="vk__mem__alloc_8h.html#ae790ab9ffaf7667fb8f62523e6897888">vmaFindMemoryTypeIndexForBufferInfo</a>(allocator, &exampleBufCreateInfo, &allocCreateInfo, &memTypeIndex);</div><div class="line"></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> = memTypeIndex;</div><div class="line"><span class="comment">// ...</span></div></div><!-- fragment --><p>Dummy buffer is needed to query driver for <code>memReq.memoryTypeBits</code>. Memory is never allocated for this buffer. You should fill structures <code>dummyBufCreateInfo</code> and <code>allocCreateInfo</code> with the same parameters as you are going to use for buffers created in your pool.</p>
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<p>When creating buffers/images allocated in that pool, provide following parameters:</p>
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<ul>
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<li><code>VkBufferCreateInfo</code>: Prefer to pass same parameters as above. Otherwise you risk creating resources in a memory type that is not suitable for them, which may result in undefined behavior. Using different <code>VK_BUFFER_USAGE_</code> flags may work, but you shouldn't create images in a pool intended for buffers or the other way around.</li>
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<li><a class="el" href="struct_vma_allocation_create_info.html">VmaAllocationCreateInfo</a>: You don't need to pass same parameters. Fill only <code>pool</code> member. Other members are ignored anyway. </li>
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</ul>
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</div></div><!-- contents -->
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<!-- start footer part -->
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<hr class="footer"/><address class="footer"><small>
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@ -499,36 +499,35 @@ vmaDestroyPool(allocator, pool);
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\section custom_memory_pools_MemTypeIndex Choosing memory type index
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When creating a pool, you must explicitly specify memory type index.
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To find the one suitable for your buffers or images, you can use code similar to the following:
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To find the one suitable for your buffers or images, you can use helper functions
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vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo().
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You need to provide structures with example parameters of buffers or images
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that you are going to create in that pool.
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\code
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VkBufferCreateInfo dummyBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
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dummyBufCreateInfo.size = 1024; // Whatever.
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dummyBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; // Change if needed.
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VkBuffer dummyBuf;
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vkCreateBuffer(device, &dummyBufCreateInfo, nullptr, &dummyBuf);
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VkMemoryRequirements memReq;
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vkGetBufferMemoryRequirements(device, dummyBuf, &memReq);
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VkBufferCreateInfo exampleBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
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exampleBufCreateInfo.size = 1024; // Whatever.
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exampleBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; // Change if needed.
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VmaAllocationCreateInfo allocCreateInfo = {};
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allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY; // Change if needed.
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uint32_t memTypeIndex;
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vmaFindMemoryTypeIndex(allocator, memReq.memoryTypeBits, &allocCreateInfo, &memTypeIndex);
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vkDestroyBuffer(device, dummyBuf, nullptr);
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vmaFindMemoryTypeIndexForBufferInfo(allocator, &exampleBufCreateInfo, &allocCreateInfo, &memTypeIndex);
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VmaPoolCreateInfo poolCreateInfo = {};
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poolCreateInfo.memoryTypeIndex = memTypeIndex;
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// ...
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\endcode
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Dummy buffer is needed to query driver for `memReq.memoryTypeBits`.
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Memory is never allocated for this buffer.
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You should fill structures `dummyBufCreateInfo` and `allocCreateInfo` with the same parameters
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as you are going to use for buffers created in your pool.
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When creating buffers/images allocated in that pool, provide following parameters:
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- `VkBufferCreateInfo`: Prefer to pass same parameters as above.
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Otherwise you risk creating resources in a memory type that is not suitable for them, which may result in undefined behavior.
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Using different `VK_BUFFER_USAGE_` flags may work, but you shouldn't create images in a pool intended for buffers
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or the other way around.
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- VmaAllocationCreateInfo: You don't need to pass same parameters. Fill only `pool` member.
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Other members are ignored anyway.
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\page defragmentation Defragmentation
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