我已经按照 www.vulkan-tutorial.com 的教程进行操作，我正在尝试将统一缓冲区拆分为 2 个单独的缓冲区，一个用于视图和投影，一个用于模型。但是，我发现一旦我向布局添加另一个缓冲区，即使我的着色器不使用它的内容，也不会渲染几何体。我从验证层中没有得到任何东西。
我发现如果两个 UBO 是相同的缓冲区，我没有问题。但是，如果我将它们分配给不同的缓冲区，屏幕上不会显示任何内容。添加了描述符集生成代码。
这是我的布局生成代码。所有值都正确提交，绑定分别为 0、1 和 2，这反映在着色器代码中。我目前甚至没有使用着色器缓冲区中的数据 - 所以这与我实际放入缓冲区的数据无关。
编辑：已在RenderDoc中打开。如果没有额外的缓冲区，我可以看到正常的 VP 缓冲区及其值。他们看起来很好。如果我添加额外的缓冲区，它不会显示，而且来自第一个缓冲区的数据都是零。
描述符集布局生成：
std::vector<VkDescriptorSetLayoutBinding> layoutBindings;
/*
newShader->features includes 3 "features", with bindings 0,1,2.
They are - uniform buffer, uniform buffer, sampler
vertex bit, vertex bit, fragment bit
*/
for (auto a : newShader->features)
{
VkDescriptorSetLayoutBinding newBinding = {};
newBinding.descriptorType = (VkDescriptorType)layoutBindingDescriptorType(a.featureType);
newBinding.binding = a.binding;
newBinding.stageFlags = (VkShaderStageFlags)layoutBindingStageFlag(a.stage);
newBinding.descriptorCount = 1;
newBinding.pImmutableSamplers = nullptr;
layoutBindings.push_back(newBinding);
}
VkDescriptorSetLayoutCreateInfo layoutCreateInfo = {};
layoutCreateInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
layoutCreateInfo.bindingCount = static_cast<uint32_t>(layoutBindings.size());
layoutCreateInfo.pBindings = layoutBindings.data();
描述符集生成：
//Create a list of layouts
std::vector<VkDescriptorSetLayout> layouts(swapChainImages.size(), voa->shaderPipeline->shaderSetLayout);
//Allocate room for the descriptors
VkDescriptorSetAllocateInfo allocInfo = {};
allocInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
allocInfo.descriptorPool = voa->shaderPipeline->descriptorPool;
allocInfo.descriptorSetCount = static_cast<uint32_t>(swapChainImages.size());
allocInfo.pSetLayouts = layouts.data();
voa->descriptorSets.resize(swapChainImages.size());
if (vkAllocateDescriptorSets(vdi->device, &allocInfo, voa->descriptorSets.data()) != VK_SUCCESS) {
throw std::runtime_error("failed to allocate descriptor sets!");
}
//For each set of commandBuffers (frames in flight +1)
for (size_t i = 0; i < swapChainImages.size(); i++) {
std::vector<VkWriteDescriptorSet> descriptorWrites;
//Buffer Info construction
for (auto a : voa->renderComponent->getMaterial()->shader->features)
{
//Create a new descriptor write
uint32_t index = descriptorWrites.size();
descriptorWrites.push_back({});
descriptorWrites[index].dstBinding = a.binding;
if (a.featureType == HE2_SHADER_FEATURE_TYPE_UNIFORM_BLOCK)
{
VkDescriptorBufferInfo bufferInfo = {};
if (a.bufferSource == HE2_SHADER_BUFFER_SOURCE_VIEW_PROJECTION_BUFFER)
{
bufferInfo.buffer = viewProjectionBuffers[i];
bufferInfo.offset = 0;
bufferInfo.range = sizeof(ViewProjectionBuffer);
}
else if (a.bufferSource == HE2_SHADER_BUFFER_SOURCE_MODEL_BUFFER)
{
bufferInfo.buffer = modelBuffers[i];
bufferInfo.offset = voa->ID * sizeof(ModelBuffer);
bufferInfo.range = sizeof(ModelBuffer);
}
//The following is the same for all Uniform buffers
descriptorWrites[index].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
descriptorWrites[index].dstSet = voa->descriptorSets[i];
descriptorWrites[index].dstArrayElement = 0;
descriptorWrites[index].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
descriptorWrites[index].descriptorCount = 1;
descriptorWrites[index].pBufferInfo = &bufferInfo;
}
else if (a.featureType == HE2_SHADER_FEATURE_TYPE_SAMPLER2D)
{
VulkanImageReference ref = VulkanTextures::images[a.imageHandle];
VkDescriptorImageInfo imageInfo = {};
imageInfo.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
imageInfo.imageView = ref.imageView;
imageInfo.sampler = defaultSampler;
descriptorWrites[index].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
descriptorWrites[index].dstSet = voa->descriptorSets[i];
descriptorWrites[index].dstArrayElement = 0;
descriptorWrites[index].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
descriptorWrites[index].descriptorCount = 1;
descriptorWrites[index].pImageInfo = &imageInfo;
}
else
{
throw std::runtime_error("Unsupported feature type present in shader");
}
}
vkUpdateDescriptorSets(vdi->device, static_cast<uint32_t>(descriptorWrites.size()), descriptorWrites.data(), 0, nullptr);
}
编辑：这是描述符集绑定代码
vkCmdBeginRenderPass(commandBuffers[i], &renderPassInfo, VK_SUBPASS_CONTENTS_INLINE);
//Very temporary Render loop. Binds every frame, very clumsy
for (int j = 0; j < max; j++)
{
VulkanObjectAttachment* voa = objectAttachments[j];
VulkanModelAttachment* vma = voa->renderComponent->getModel()->getComponent<VulkanModelAttachment>();
if (vma->indices == 0) continue;
vkCmdBindPipeline(commandBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, voa->shaderPipeline->pipeline);
VkBuffer vertexBuffers[] = { vma->vertexBuffer };
VkDeviceSize offsets[] = { 0 };
vkCmdBindVertexBuffers(commandBuffers[i], 0, 1, vertexBuffers, offsets);
vkCmdBindIndexBuffer(commandBuffers[i], vma->indexBuffer, 0, VK_INDEX_TYPE_UINT32);
vkCmdBindDescriptorSets(commandBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, voa->shaderPipeline->pipelineLayout, 0, 1, &voa->descriptorSets[i], 0, nullptr);
vkCmdDrawIndexed(commandBuffers[i], static_cast<uint32_t>(vma->indices), 1, 0, 0, 0);
}
vkCmdEndRenderPass(commandBuffers[i]);
缓冲区更新代码：
ViewProjectionBuffer ubo = {};
ubo.view = HE2_Camera::main->getCameraMatrix();
ubo.proj = HE2_Camera::main->getProjectionMatrix();
ubo.proj[1][1] *= -1;
ubo.model = a->object->getModelMatrix();
void* data;
vmaMapMemory(allocator, a->mvpAllocations[i], &data);
memcpy(data, &ubo, sizeof(ubo));
vmaUnmapMemory(allocator, a->mvpAllocations[i]);
}
std::vector<ModelBuffer> modelBuffersData;
for (VulkanObjectAttachment* voa : objectAttachments)
{
ModelBuffer mb = {};
mb.model = voa->object->getModelMatrix();
modelBuffersData.push_back(mb);
void* data;
vmaMapMemory(allocator, modelBuffersAllocation[i], &data);
memcpy(data, &modelBuffersData, sizeof(ModelBuffer) * modelBuffersData.size());
vmaUnmapMemory(allocator, modelBuffersAllocation[i]);
我发现了问题 - 可悲的是，不是 Vulkan 问题，而是C++语法问题。无论如何，我都会解释它，但如果您将来访问此页面，则可能不是您的问题。
我在循环中生成我的描述符写入。它们存储在向量中，然后在循环结束时更新
std::vector<VkDescriptorWrite> descriptorWrites;
for(int i = 0; i < shader.features.size); i++)
{
//Various stuff to the descriptor write
}
vkUpdateDescriptorSets(vdi->device, static_cast<uint32_t>(descriptorWrites.size()), descriptorWrites.data(), 0, nullptr);
描述符写入的一个参数是pImageInfo或pBufferInfo。它们指向包含该缓冲区或图像的特定数据的结构。我在循环中填写了这些
{//Within the loop above
//...
VkDescriptorBufferInfo bufferInfo = {};
bufferInfo.buffer = myBuffer;
descriptorWrites[i].pBufferInfo = &bufferInfo;
//...
}
由于这些是通过引用而不是值传递的，因此在更新时，描述符写入引用原始结构中的数据。但是，由于原始结构是在循环中创建的，并且vkUpdateDescriptors行在循环之外，因此在读取该结构时，它已超出范围并被删除。
虽然这应该会导致未定义的行为，但我只能想象，因为循环结束和更新调用之间没有新变量，内存仍然读取循环中最后一个描述符的内容。因此，所有描述符都会读取该内存，并将最后一个描述符Write中的资源推送给它们。只需在循环开始时将VkDescriptorBufferInfo放在自己的向量中即可修复所有问题。
在我看来，您在此处设置的偏移量导致VkWriteDescriptorSet读取溢出内存：
else if (a.bufferSource == HE2_SHADER_BUFFER_SOURCE_MODEL_BUFFER)
{
bufferInfo.buffer = modelBuffers[i];
bufferInfo.offset = voa->ID * sizeof(ModelBuffer);
bufferInfo.range = sizeof(ModelBuffer);
}
如果你每帧只更新缓冲区的一部分，你会做这样的事情：
bufferInfo.buffer = mvpBuffer[i];
bufferInfo.offset = sizeof(mat4[]{viewMat, projMat});
bufferInfo.range = sizeof(modelMat);
如果将模型放在另一个缓冲区中，则可能需要为描述符集创建不同的绑定，并且模型数据的bufferInfo如下所示：
bufferInfo.buffer = modelBuffer[i];
bufferInfo.offset = 0;
bufferInfo.range = sizeof(modelMat);