Vulkan Progress

Entry posted by Josh · May 27, 2019

1,726 views

I was going to write about my thoughts on Vulkan, about what I like and don't like, what could be improved, and what ramifications this has for developers and the industry. But it doesn't matter what I think. This is the way things are going, and I have no say in that. I can only respond to these big industry-wide changes and make it work to my advantage. Overall, Vulkan does help us, in both a technical and business sense. That's as much as I feel like explaining.

Beta subscribers can try the demo out here:

This is the code it takes to add a depth buffer to the swap chain ?:

//----------------------------------------------------------------
// Depth attachment
//----------------------------------------------------------------

auto depthformat = VK_FORMAT_D24_UNORM_S8_UINT;
VkImage depthimage = nullptr;

VkImageCreateInfo image_info = {};
image_info.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
image_info.pNext = NULL;
image_info.imageType = VK_IMAGE_TYPE_2D;
image_info.format = depthformat;
image_info.extent.width = chaininfo.imageExtent.width;
image_info.extent.height = chaininfo.imageExtent.height;
image_info.extent.depth = 1;
image_info.mipLevels = 1;
image_info.arrayLayers = 1;
image_info.samples = VK_SAMPLE_COUNT_1_BIT;
image_info.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
image_info.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
image_info.queueFamilyIndexCount = 0;
image_info.pQueueFamilyIndices = NULL;
image_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
image_info.flags = 0;
vkCreateImage(device->device, &image_info, nullptr, &depthimage);

VkMemoryRequirements memRequirements;
vkGetImageMemoryRequirements(device->device, depthimage, &memRequirements);

VmaAllocation alllocation = {};
VmaAllocationInfo allocinfo = {};
VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
VkAssert(vmaAllocateMemory(GameEngine::Get()->renderingthreadmanager->instance->allocator, &memRequirements, &allocCreateInfo, &alllocation, &allocinfo));
VkAssert(vkBindImageMemory(device->device, depthimage, allocinfo.deviceMemory, allocinfo.offset));

VkImageView depthImageView;

VkImageViewCreateInfo view_info = {};
view_info.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
view_info.pNext = NULL;
view_info.image = depthimage;
view_info.format = depthformat;
view_info.components.r = VK_COMPONENT_SWIZZLE_R;
view_info.components.g = VK_COMPONENT_SWIZZLE_G;
view_info.components.b = VK_COMPONENT_SWIZZLE_B;
view_info.components.a = VK_COMPONENT_SWIZZLE_A;
view_info.subresourceRange.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT;
view_info.subresourceRange.baseMipLevel = 0;
view_info.subresourceRange.levelCount = 1;
view_info.subresourceRange.baseArrayLayer = 0;
view_info.subresourceRange.layerCount = 1;
view_info.viewType = VK_IMAGE_VIEW_TYPE_2D;
view_info.flags = 0;

VkAssert(vkCreateImageView(device->device, &view_info, NULL, &depthImageView));

VkAttachmentDescription depthAttachment = {};
depthAttachment.format = depthformat;
depthAttachment.samples = VK_SAMPLE_COUNT_1_BIT;
depthAttachment.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
depthAttachment.storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
depthAttachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
depthAttachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
depthAttachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
depthAttachment.finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

VkAttachmentReference depthAttachmentRef = {};
depthAttachmentRef.attachment = 1;
depthAttachmentRef.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

VkPipelineDepthStencilStateCreateInfo depthStencil = {};
depthStencil.sType = VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO;
depthStencil.depthTestEnable = VK_TRUE;
depthStencil.depthWriteEnable = VK_TRUE;
depthStencil.depthCompareOp = VK_COMPARE_OP_LESS;
depthStencil.depthBoundsTestEnable = VK_FALSE;
depthStencil.minDepthBounds = 0.0f;
depthStencil.maxDepthBounds = 1.0f;
depthStencil.stencilTestEnable = VK_FALSE;
depthStencil.front = {};
depthStencil.back = {};

I was hoping I would put a month into it and be up to speed with where we were with OpenGL, but it is much more complicated than that. Using Vulkan is going to be tough but we will get through it and I think the benefits will be worthwhile:

Vulkan makes our new renderer 80% faster
Better compatibility (Mac, Intel on Linux)
There's a lot of demand for Vulkan products thanks to Khronos and Valve's promotion.