From 61de98d651d36235c238f24d9c45dc541697b076 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Sat, 22 Oct 2022 21:16:12 +1000
Subject: [PATCH] Vulkan: Support running surfaceless

---
 common/Vulkan/Context.cpp                |  7 +++----
 pcsx2/Frontend/VulkanHostDisplay.cpp     |  7 ++++++-
 pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp | 12 +++++-------
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/common/Vulkan/Context.cpp b/common/Vulkan/Context.cpp
index 33ee58321b..db275d09ba 100644
--- a/common/Vulkan/Context.cpp
+++ b/common/Vulkan/Context.cpp
@@ -536,7 +536,7 @@ namespace Vulkan
 			Console.Error("Vulkan: Failed to find an acceptable graphics queue.");
 			return false;
 		}
-		if (surface && m_present_queue_family_index == queue_family_count)
+		if (surface != VK_NULL_HANDLE && m_present_queue_family_index == queue_family_count)
 		{
 			Console.Error("Vulkan: Failed to find an acceptable present queue.");
 			return false;
@@ -570,7 +570,7 @@ namespace Vulkan
 		}};
 
 		device_info.queueCreateInfoCount = 1;
-		if (m_graphics_queue_family_index != m_present_queue_family_index)
+		if (surface != VK_NULL_HANDLE && m_graphics_queue_family_index != m_present_queue_family_index)
 		{
 			device_info.queueCreateInfoCount = 2;
 		}
@@ -1445,8 +1445,7 @@ namespace Vulkan
 		}
 
 		const VkSubpassDescriptionFlags subpass_flags =
-			(key.color_feedback_loop && g_vulkan_context->GetOptionalExtensions().vk_arm_rasterization_order_attachment_access)
-			? VK_SUBPASS_DESCRIPTION_RASTERIZATION_ORDER_ATTACHMENT_COLOR_ACCESS_BIT_ARM : 0;
+			(key.color_feedback_loop && g_vulkan_context->GetOptionalExtensions().vk_arm_rasterization_order_attachment_access) ? VK_SUBPASS_DESCRIPTION_RASTERIZATION_ORDER_ATTACHMENT_COLOR_ACCESS_BIT_ARM : 0;
 		const VkSubpassDescription subpass = {subpass_flags, VK_PIPELINE_BIND_POINT_GRAPHICS, input_reference_ptr ? 1u : 0u,
 			input_reference_ptr ? input_reference_ptr : nullptr, color_reference_ptr ? 1u : 0u,
 			color_reference_ptr ? color_reference_ptr : nullptr, nullptr, depth_reference_ptr, 0, nullptr};
diff --git a/pcsx2/Frontend/VulkanHostDisplay.cpp b/pcsx2/Frontend/VulkanHostDisplay.cpp
index 2cefb50225..aee303647c 100644
--- a/pcsx2/Frontend/VulkanHostDisplay.cpp
+++ b/pcsx2/Frontend/VulkanHostDisplay.cpp
@@ -311,7 +311,12 @@ bool VulkanHostDisplay::HasSurface() const
 
 bool VulkanHostDisplay::CreateImGuiContext()
 {
-	return ImGui_ImplVulkan_Init(m_swap_chain->GetClearRenderPass());
+	const VkRenderPass render_pass =
+		m_swap_chain ? m_swap_chain->GetClearRenderPass() : g_vulkan_context->GetRenderPass(VK_FORMAT_R8G8B8A8_UNORM, VK_FORMAT_UNDEFINED);
+	if (render_pass == VK_NULL_HANDLE)
+		return false;
+
+	return ImGui_ImplVulkan_Init(render_pass);
 }
 
 void VulkanHostDisplay::DestroyImGuiContext()
diff --git a/pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp b/pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp
index db5b4cccb0..ed8c2f74f7 100644
--- a/pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp
+++ b/pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp
@@ -1513,13 +1513,11 @@ bool GSDeviceVK::CompilePresentPipelines()
 {
 	// we may not have a swap chain if running in headless mode.
 	Vulkan::SwapChain* swapchain = static_cast<Vulkan::SwapChain*>(g_host_display->GetSurface());
-	if (swapchain)
-	{
-		m_swap_chain_render_pass =
-			g_vulkan_context->GetRenderPass(swapchain->GetSurfaceFormat().format, VK_FORMAT_UNDEFINED);
-		if (!m_swap_chain_render_pass)
-			return false;
-	}
+	m_swap_chain_render_pass = swapchain ?
+								   swapchain->GetClearRenderPass() :
+                                   g_vulkan_context->GetRenderPass(VK_FORMAT_R8G8B8A8_UNORM, VK_FORMAT_UNDEFINED);
+	if (!m_swap_chain_render_pass)
+		return false;
 
 	std::optional<std::string> shader = Host::ReadResourceFileToString("shaders/vulkan/present.glsl");
 	if (!shader)