'Vulkan: How to add descriptors for a Dynamic Uniform Buffer

I have been following a tutorial for Vulkan and am trying to implement a dynamic uniform buffer.

I currently have descriptors for a uniform buffer and a combined image sampler but i am not sure how to add another descriptor for a dynamic uniform buffer.

I have made some attempts but i get a lot of errors so I'm probably doing something wrong

Code (for the descriptors that are working correctly):

void createDescriptorSetLayout() {

        VkDescriptorSetLayoutBinding uboLayoutBinding{};
        uboLayoutBinding.binding = 0;
        uboLayoutBinding.descriptorCount = 1;
        uboLayoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
        uboLayoutBinding.pImmutableSamplers = nullptr;
        uboLayoutBinding.stageFlags = VK_SHADER_STAGE_VERTEX_BIT;

        VkDescriptorSetLayoutBinding samplerLayoutBinding{};
        samplerLayoutBinding.binding = 1;
        samplerLayoutBinding.descriptorCount = 1;
        samplerLayoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
        samplerLayoutBinding.pImmutableSamplers = nullptr;
        samplerLayoutBinding.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;

        std::array<VkDescriptorSetLayoutBinding, 2> bindings = {uboLayoutBinding, samplerLayoutBinding};
        VkDescriptorSetLayoutCreateInfo layoutInfo{};
        layoutInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
        layoutInfo.bindingCount = static_cast<uint32_t>(bindings.size());
        layoutInfo.pBindings = bindings.data();



        if (vkCreateDescriptorSetLayout(device, &layoutInfo, nullptr, &descriptorSetLayout) != VK_SUCCESS) {
            throw std::runtime_error("failed to create descriptor set layout!");
        }
    }

void createDescriptorPool() {

        std::array<VkDescriptorPoolSize, 2> poolSizes{};
        poolSizes[0].type = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
        poolSizes[0].descriptorCount = static_cast<uint32_t>(MAX_FRAMES_IN_FLIGHT);
        poolSizes[1].type = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
        poolSizes[1].descriptorCount = static_cast<uint32_t>(MAX_FRAMES_IN_FLIGHT);

        VkDescriptorPoolCreateInfo poolInfo{};
        poolInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
        poolInfo.poolSizeCount = static_cast<uint32_t>(poolSizes.size());
        poolInfo.pPoolSizes = poolSizes.data();
        poolInfo.maxSets = static_cast<uint32_t>(MAX_FRAMES_IN_FLIGHT);

        if (vkCreateDescriptorPool(device, &poolInfo, nullptr, &descriptorPool) != VK_SUCCESS) {
            throw std::runtime_error("failed to create descriptor pool!");
        }
    }

void createDescriptorSets() {

        std::vector<VkDescriptorSetLayout> layouts(MAX_FRAMES_IN_FLIGHT, descriptorSetLayout);
        VkDescriptorSetAllocateInfo allocInfo{};
        allocInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
        allocInfo.descriptorPool = descriptorPool;
        allocInfo.descriptorSetCount = static_cast<uint32_t>(MAX_FRAMES_IN_FLIGHT);
        allocInfo.pSetLayouts = layouts.data();

        descriptorSets.resize(MAX_FRAMES_IN_FLIGHT);
        if (vkAllocateDescriptorSets(device, &allocInfo, descriptorSets.data()) != VK_SUCCESS) {

            throw std::runtime_error("failed to allocate descriptor sets!");

        }

        for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {

            VkDescriptorBufferInfo bufferInfo{};
            bufferInfo.buffer = uniformBuffers[i];
            bufferInfo.offset = 0;
            bufferInfo.range = sizeof(UniformBufferObject);

            VkDescriptorImageInfo imageInfo{};
            imageInfo.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
            imageInfo.imageView = textureImageView;
            imageInfo.sampler = textureSampler;

            std::array<VkWriteDescriptorSet, 2> descriptorWrites{};

            descriptorWrites[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
            descriptorWrites[0].dstSet = descriptorSets[i];
            descriptorWrites[0].dstBinding = 0;
            descriptorWrites[0].dstArrayElement = 0;
            descriptorWrites[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
            descriptorWrites[0].descriptorCount = 1;
            descriptorWrites[0].pBufferInfo = &bufferInfo;

            descriptorWrites[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
            descriptorWrites[1].dstSet = descriptorSets[i];
            descriptorWrites[1].dstBinding = 1;
            descriptorWrites[1].dstArrayElement = 0;
            descriptorWrites[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
            descriptorWrites[1].descriptorCount = 1;
            descriptorWrites[1].pImageInfo = &imageInfo;

            vkUpdateDescriptorSets(device, static_cast<uint32_t>(descriptorWrites.size()), descriptorWrites.data(), 0, nullptr);
        }
    }

(MAX_FRAMES_IN_FLIGHT = 2)

c++graphicsvulkandescriptor


Solution 1:[1]

It is mostly identical to the non-dynamic uniform, except you provide offset afterwards when binding it. You already seem to have all the relevant code, except you replace VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER with VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 krOoze

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