From 620c2d40d9efb4595924cf9bda53ddd77fd33c5a Mon Sep 17 00:00:00 2001
From: shg8 <me@stevengao.net>
Date: Mon, 1 Apr 2024 21:37:22 -0500
Subject: [PATCH] OXR infra

---
 apps/vr_viewer/src/OXRContext.cpp | 51 +++++++++++++++++++++++++++----
 apps/vr_viewer/src/OXRContext.h   | 16 +++++++---
 apps/vr_viewer/src/VRViewer.cpp   |  9 ++++++
 apps/vr_viewer/src/VRViewer.h     |  3 ++
 4 files changed, 69 insertions(+), 10 deletions(-)

diff --git a/apps/vr_viewer/src/OXRContext.cpp b/apps/vr_viewer/src/OXRContext.cpp
index ceba80a..73a6978 100644
--- a/apps/vr_viewer/src/OXRContext.cpp
+++ b/apps/vr_viewer/src/OXRContext.cpp
@@ -10,10 +10,6 @@
 #include "spdlog/spdlog.h"
 
 void OXRContext::setup() {
-    setupOXR();
-}
-
-void OXRContext::setupOXR() {
     bool vulkanSupported = OXR::isExtensionSupported(XR_KHR_VULKAN_ENABLE_EXTENSION_NAME);
     if (!vulkanSupported) {
         throw std::runtime_error("Vulkan not supported");
@@ -22,8 +18,8 @@ void OXRContext::setupOXR() {
     createInstance();
     createSystem();
     setupViews();
-    getRequiredVulkanInstanceExtensions();
-    getRequiredVulkanDeviceExtensions();
+    std::ignore = getRequiredVulkanInstanceExtensions();
+    std::ignore = getRequiredVulkanDeviceExtensions();
 }
 
 void OXRContext::createInstance() {
@@ -180,3 +176,46 @@ void * OXRContext::getPhysicalDevice(void *instance) const {
 
     return physicalDevice;
 }
+
+void OXRContext::createSession(void *vkInstance, void *vkPhysicalDevice, void *vkDevice, uint32_t vkQueueFamilyIndex,
+    uint32_t vkQueueIndex) {
+    XrGraphicsBindingVulkanKHR graphicsBinding = {XR_TYPE_GRAPHICS_BINDING_VULKAN_KHR};
+    graphicsBinding.instance = static_cast<VkInstance>(vkInstance);
+    graphicsBinding.physicalDevice = static_cast<VkPhysicalDevice>(vkPhysicalDevice);
+    graphicsBinding.device = static_cast<VkDevice>(vkDevice);
+    graphicsBinding.queueFamilyIndex = vkQueueFamilyIndex;
+    graphicsBinding.queueIndex = vkQueueIndex;
+
+    XrSessionCreateInfo createInfo = {XR_TYPE_SESSION_CREATE_INFO};
+    createInfo.next = &graphicsBinding;
+    createInfo.systemId = systemId;
+
+    auto result = xrCreateSession(oxrInstance, &createInfo, &oxrSession);
+    if (XR_FAILED(result)) {
+        throw std::runtime_error("Failed to create OpenXR session");
+    }
+
+    spdlog::debug("Created OpenXR session");
+}
+
+void OXRContext::createReferenceSpace() {
+    XrPosef identityPose = {{0, 0, 0, 1}, {0, 0, 0}};
+    XrReferenceSpaceCreateInfo createInfo = {XR_TYPE_REFERENCE_SPACE_CREATE_INFO};
+    createInfo.poseInReferenceSpace = identityPose;
+    createInfo.referenceSpaceType = XR_REFERENCE_SPACE_TYPE_LOCAL;
+
+    auto result = xrCreateReferenceSpace(oxrSession, &createInfo, &localSpace);
+    if (XR_FAILED(result)) {
+        throw std::runtime_error("Failed to create OpenXR reference space");
+    }
+}
+
+void OXRContext::beginSession() {
+    XrSessionBeginInfo beginInfo = {XR_TYPE_SESSION_BEGIN_INFO};
+    beginInfo.primaryViewConfigurationType = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO;
+
+    auto result = xrBeginSession(oxrSession, &beginInfo);
+    if (XR_FAILED(result)) {
+        throw std::runtime_error("Failed to begin OpenXR session");
+    }
+}
diff --git a/apps/vr_viewer/src/OXRContext.h b/apps/vr_viewer/src/OXRContext.h
index 2cf1771..e54a686 100644
--- a/apps/vr_viewer/src/OXRContext.h
+++ b/apps/vr_viewer/src/OXRContext.h
@@ -11,12 +11,20 @@ class OXRContext {
 public:
     void setup();
     void* getPhysicalDevice(void *instance) const;
+
+    void createSession(void *vkInstance, void *vkPhysicalDevice, void *vkDevice, uint32_t vkQueueFamilyIndex,
+    uint32_t vkQueueIndex);
+
+    void createReferenceSpace();
+
+    void beginSession();
+
 private:
-    XrInstance oxrInstance;
-    XrSystemId systemId;
+    XrInstance oxrInstance = XR_NULL_HANDLE;
+    XrSystemId systemId = XR_NULL_SYSTEM_ID;
     XrViewConfigurationView views[2] = {{XR_TYPE_VIEW_CONFIGURATION_VIEW}, {XR_TYPE_VIEW_CONFIGURATION_VIEW}};
-
-    void setupOXR();
+    XrSession oxrSession = XR_NULL_HANDLE;
+    XrSpace localSpace = XR_NULL_HANDLE;
 
     void createInstance();
 
diff --git a/apps/vr_viewer/src/VRViewer.cpp b/apps/vr_viewer/src/VRViewer.cpp
index 87b20fe..07b6532 100644
--- a/apps/vr_viewer/src/VRViewer.cpp
+++ b/apps/vr_viewer/src/VRViewer.cpp
@@ -1,9 +1,11 @@
 #include "VRViewer.h"
 
 #include <memory>
+#include <openxr/openxr_platform.h>
 
 #include "OXRContext.h"
 #include "3dgs.h"
+#include "spdlog/spdlog.h"
 
 void VRViewer::run() {
     context = std::make_shared<OXRContext>();
@@ -13,3 +15,10 @@ void VRViewer::run() {
     configuration.getPhysicalDevice = std::bind(&OXRContext::getPhysicalDevice, context.get(), std::placeholders::_1);
 }
 
+void VRViewer::finishSetup(void *vkInstance, void *vkPhysicalDevice, void *vkDevice, uint32_t vkQueueFamilyIndex,
+    uint32_t vkQueueIndex) {
+    context->createSession(vkInstance, vkPhysicalDevice, vkDevice, vkQueueFamilyIndex, vkQueueIndex);
+    context->createReferenceSpace();
+    context->beginSession();
+}
+
diff --git a/apps/vr_viewer/src/VRViewer.h b/apps/vr_viewer/src/VRViewer.h
index ea2bac9..e388b2e 100644
--- a/apps/vr_viewer/src/VRViewer.h
+++ b/apps/vr_viewer/src/VRViewer.h
@@ -1,6 +1,7 @@
 #ifndef OPENXRVIEWER_H
 #define OPENXRVIEWER_H
 #include <args.hxx>
+#include <barrier>
 #include <memory>
 #include <utility>
 
@@ -26,6 +27,8 @@ class VRViewer {
 
     void run();
 
+    void finishSetup(void *vkInstance, void *vkPhysicalDevice, void *vkDevice, uint32_t vkQueueFamilyIndex, uint32_t vkQueueIndex);
+
 private:
     Configuration config;
     std::shared_ptr<OXRContext> context = nullptr;