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XR.cpp
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XR.cpp
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#include "XR.hpp"
#include "GL.hpp"
#ifdef __ANDROID__
//android stuff:
#include <jni.h>
#define XR_USE_GRAPHICS_API_OPENGL_ES
#define XR_USE_PLATFORM_ANDROID
#include <openxr/openxr_platform.h>
#else
//linux stuff:
#include <X11/Xlib.h>
#include <GL/glx.h>
#define XR_USE_GRAPHICS_API_OPENGL
#define XR_USE_PLATFORM_XLIB
#include <openxr/openxr_platform.h>
#include <SDL_syswm.h>
#endif
#include "gl_errors.hpp"
#include <openxr/openxr_reflection.h>
#include <iostream>
#include <sstream>
#include <cstring>
#include <vector>
#include <array>
#include <cassert>
#include <thread>
XR *xr = nullptr;
XR::XR(
PlatformInfo const &platform,
std::string const &application_name,
uint32_t application_version,
std::string const &engine_name,
uint32_t engine_version
) {
std::cout << "--- initializing OpenXR ---" << std::endl;
#ifdef __ANDROID__
{ //call xrInitializeLoaderKHR (based on XrApp.cpp from OVR OpenXR SDK):
PFN_xrInitializeLoaderKHR xrInitializeLoaderKHR;
xrGetInstanceProcAddr(XR_NULL_HANDLE, "xrInitializeLoaderKHR", reinterpret_cast< PFN_xrVoidFunction* >(&xrInitializeLoaderKHR));
if (xrInitializeLoaderKHR != NULL) {
XrLoaderInitInfoAndroidKHR loader_init_info = {XR_TYPE_LOADER_INIT_INFO_ANDROID_KHR};
loader_init_info.applicationVM = platform.application_vm;
loader_init_info.applicationContext = platform.application_activity; //TODO: is this right? OVR sample does it, but docs say this should be a "android.content.Context" (which seems different from the Activity below)
if (XrResult res = xrInitializeLoaderKHR(reinterpret_cast< XrLoaderInitInfoBaseHeaderKHR *>(&loader_init_info));
res != XR_SUCCESS) {
std::cerr << "WARNING: xrInitializeLoaderKHR failed: " << to_string(res) << std::endl;
}
}
}
#endif //__ANDROID__
XrInstanceCreateInfo create_info{XR_TYPE_INSTANCE_CREATE_INFO};
//with reference to openxr_program.cpp from openxr-sdk-source + the openxr specification
//XR_MAX_APPLICATION_NAME_SIZE-1 because std::string.size() doesn't count null bytes
std::memcpy(create_info.applicationInfo.applicationName, application_name.c_str(),
std::min(application_name.size(), size_t(XR_MAX_APPLICATION_NAME_SIZE-1)) );
create_info.applicationInfo.applicationVersion = application_version;
std::memcpy(create_info.applicationInfo.engineName, engine_name.c_str(),
std::min(engine_name.size(), size_t(XR_MAX_ENGINE_NAME_SIZE-1)) );
create_info.applicationInfo.engineVersion = engine_version;
create_info.applicationInfo.apiVersion = XR_CURRENT_API_VERSION;
#ifdef __ANDROID__
//extra android-specific creation info:
XrInstanceCreateInfoAndroidKHR create_info_android{XR_TYPE_INSTANCE_CREATE_INFO_ANDROID_KHR};
create_info_android.applicationVM = platform.application_vm;
create_info_android.applicationActivity = platform.application_activity;
create_info.next = &create_info_android;
#endif //__ANDROID__
std::vector< const char * > extensions{
#ifdef __ANDROID__
XR_KHR_ANDROID_CREATE_INSTANCE_EXTENSION_NAME,
XR_KHR_OPENGL_ES_ENABLE_EXTENSION_NAME,
#else
XR_KHR_OPENGL_ENABLE_EXTENSION_NAME,
#endif
};
create_info.enabledExtensionCount = uint32_t(extensions.size());
create_info.enabledExtensionNames = extensions.data();
if (XrResult res = xrCreateInstance(&create_info, &instance);
res != XR_SUCCESS) {
instance = XR_NULL_HANDLE; //just in case create broke something
throw std::runtime_error("Failed to create OpenXR instance: " + to_string(res));
}
{ //Query the instance to learn what runtime this is using:
XrInstanceProperties properties{XR_TYPE_INSTANCE_PROPERTIES};
if (XrResult res = xrGetInstanceProperties(instance, &properties);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get OpenXR instance properties: " + to_string(res));
}
//Information:
std::cout << "OpenXR Runtime is '" << properties.runtimeName << "', version "
<< (properties.runtimeVersion >> 48)
<< "." << ((properties.runtimeVersion >> 32) & 0xffff)
<< "." << (properties.runtimeVersion & 0xffffffff)
<< std::endl;
}
//----- now select the *system* -----
XrSystemGetInfo system_info{XR_TYPE_SYSTEM_GET_INFO};
system_info.formFactor = XR_FORM_FACTOR_HEAD_MOUNTED_DISPLAY;
XrSystemId system_id{XR_NULL_SYSTEM_ID};
if (XrResult res = xrGetSystem(instance, &system_info, &system_id);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get a system: " + to_string(res));
}
{ //Query the system to learn a bit more:
XrSystemProperties properties{XR_TYPE_SYSTEM_PROPERTIES};
if (XrResult res = xrGetSystemProperties(instance, system_id, &properties);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get system properties: " + to_string(res));
}
std::cout << "System is '" << properties.systemName << "' with vendorId " << properties.vendorId << "." << std::endl;
std::cout << " graphics: maxSwapchainImageWidth x Height is " << properties.graphicsProperties.maxSwapchainImageWidth << "x" << properties.graphicsProperties.maxSwapchainImageHeight << ", maxLayerCount is " << properties.graphicsProperties.maxLayerCount << "." << std::endl;
std::cout << " tracking: orientationTracking is " << (properties.trackingProperties.orientationTracking == XR_TRUE ? "true" : "false");
std::cout << ", positionTracking is " << (properties.trackingProperties.positionTracking == XR_TRUE ? "true" : "false") << "." << std::endl;
//note that the next field might actually have a long list of structures that might be interesting; depending on (whatever).
}
//----- graphics requirements -----
//NOTE: this is required before xrCreateSession(!)
//based on ovr-openxr-sdk's XrApp.cpp
{ //report OpenGL[ES} version support
#ifdef __ANDROID__
//OpenGL ES version:
PFN_xrGetOpenGLESGraphicsRequirementsKHR xrGetOpenGLESGraphicsRequirementsKHR = nullptr;
if (XrResult res = xrGetInstanceProcAddr(instance, "xrGetOpenGLESGraphicsRequirementsKHR",(PFN_xrVoidFunction*)(&xrGetOpenGLESGraphicsRequirementsKHR));
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get xrGetOpenGLESGraphicsRequrirementsKHR function pointer: " + to_string(res));
}
XrGraphicsRequirementsOpenGLESKHR graphics_requirements = {XR_TYPE_GRAPHICS_REQUIREMENTS_OPENGL_ES_KHR};
if (XrResult res = xrGetOpenGLESGraphicsRequirementsKHR(instance, system_id, &graphics_requirements);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get OpenGLES graphics requirements: " + to_string(res));
}
#else
//OpenGL version:
PFN_xrGetOpenGLGraphicsRequirementsKHR xrGetOpenGLGraphicsRequirementsKHR = nullptr;
if (XrResult res = xrGetInstanceProcAddr(instance, "xrGetOpenGLGraphicsRequirementsKHR",(PFN_xrVoidFunction*)(&xrGetOpenGLGraphicsRequirementsKHR));
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get xrGetOpenGLGraphicsRequrirementsKHR function pointer: " + to_string(res));
}
XrGraphicsRequirementsOpenGLKHR graphics_requirements = {XR_TYPE_GRAPHICS_REQUIREMENTS_OPENGL_KHR};
if (XrResult res = xrGetOpenGLGraphicsRequirementsKHR(instance, system_id, &graphics_requirements);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get OpenGL graphics requirements: " + to_string(res));
}
#endif
std::cout << "OpenGL requirements:\n";
std::cout << " min supported version: " << (graphics_requirements.minApiVersionSupported >> 48) << "." << ((graphics_requirements.minApiVersionSupported >> 32) & 0xffff) << "\n";
std::cout << " max known supported version: " << (graphics_requirements.maxApiVersionSupported >> 48) << "." << ((graphics_requirements.maxApiVersionSupported >> 32) & 0xffff) << " (OpenXR spec says newer may work fine, though)\n";
std::cout.flush();
{ //compare to OpenGL's reported version:
GLint major = 0;
GLint minor = 0;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
std::cout << "Current OpenGL version is " << major << "." << minor << std::endl;
if (XR_MAKE_VERSION(major, minor, 0) < graphics_requirements.minApiVersionSupported) {
std::cerr << "ERROR: reported OpenGL version (" << major << "." << minor << ") is less than the minimum that OpenXR reports as supporting. (Continuing, but don't expect things to work.)" << std::endl;
}
if (XR_MAKE_VERSION(major, minor, 0) > graphics_requirements.maxApiVersionSupported) {
std::cerr << "WARNING: reported OpenGL version (" << major << "." << minor << ") is larger the maximum that OpenXR reports supporting. (Continuing, since this could still be okay.)" << std::endl;
}
}
}
{ //----- session creation -----
#ifdef __ANDROID__
//set up XrGraphicsBindingOpenGLESAndroid structure (OpenGL ES on Android):
XrGraphicsBindingOpenGLESAndroidKHR binding{XR_TYPE_GRAPHICS_BINDING_OPENGL_ES_ANDROID_KHR};
binding.display = platform.egl_display;
binding.config = platform.egl_config;
binding.context = platform.egl_context;
#else //__ANDROID__
//set up XrGraphicsBindingOpenGLXlibKHR structure (OpenGL on Xlib bindings):
//getting window manager info as per example in SDL_syswm.h comment:
SDL_SysWMinfo info;
SDL_VERSION(&info.version);
if ( !SDL_GetWindowWMInfo(window, &info) ) {
throw std::runtime_error("Failed to get window manager info from SDL: " + std::string(SDL_GetError()));
}
//to extract the window's Visual (and, eventually, visualid):
XWindowAttributes window_attributes;
if (Status res = XGetWindowAttributes(info.info.x11.display, info.info.x11.window, &window_attributes);
res == 0) {
throw std::runtime_error("Failed to get window attributes (needed to extract visual).");
}
//appears to be the case on SDL's x11 opengl driver:
GLXContext glx_context = reinterpret_cast< GLXContext >(context);
//How to get the current fbconfig; thanks to a suggestion from:
// https://stackoverflow.com/questions/74104449/getting-the-current-glxfbconfig-in-glx
int fbconfig_id = 0;
if (int ret = glXQueryContext(info.info.x11.display, glx_context, GLX_FBCONFIG_ID, &fbconfig_id);
ret != Success) {
throw std::runtime_error("Failed to query FBConfig id from glX context.");
}
int fb_configs_size = 0;
int attribs[3] = { GLX_FBCONFIG_ID, fbconfig_id, None };
GLXFBConfig *fb_configs = glXChooseFBConfig(
info.info.x11.display,
XScreenNumberOfScreen(window_attributes.screen),
attribs,
&fb_configs_size);
if (fb_configs == NULL || fb_configs_size == 0) {
throw std::runtime_error("Failed to select FBConfig by id.");
}
if (fb_configs_size > 1) {
std::cerr << "WARNING: got more than one config with the id from the current context; using the first, but this may break things." << std::endl;
}
XrGraphicsBindingOpenGLXlibKHR binding{XR_TYPE_GRAPHICS_BINDING_OPENGL_XLIB_KHR};
binding.xDisplay = info.info.x11.display;
binding.visualid = XVisualIDFromVisual(window_attributes.visual);
binding.glxFBConfig = fb_configs[0];
binding.glxDrawable = glXGetCurrentDrawable();
binding.glxContext = glx_context;
#endif
XrSessionCreateInfo create_info{XR_TYPE_SESSION_CREATE_INFO};
create_info.next = &binding;
create_info.createFlags = 0; //no flags specified yet
create_info.systemId = system_id;
if (XrResult res = xrCreateSession(instance, &create_info, &session);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to create session: " + to_string(res));
}
#ifndef __ANDROID__
//on linux, must free fb_configs:
XFree(fb_configs); //"use XFree to free the memory returned by glXChooseFBConfig"
#endif //__ANDROID__
}
{ //create stage space:
XrReferenceSpaceCreateInfo create_info{XR_TYPE_REFERENCE_SPACE_CREATE_INFO};
create_info.referenceSpaceType = XR_REFERENCE_SPACE_TYPE_STAGE;
create_info.poseInReferenceSpace.orientation.w = 1.0f; //everything else can be zero from value-initialization, but orientation needs to be unit-length
if (XrResult res = xrCreateReferenceSpace(session, &create_info, &stage);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to create stage space: " + to_string(res));
}
}
{ //look up view information
std::array< XrViewConfigurationView, 2 > views;
views.fill(XrViewConfigurationView{XR_TYPE_VIEW_CONFIGURATION_VIEW});
const uint32_t views_capacity = uint32_t(views.size());
uint32_t views_count = 0;
if (XrResult res = xrEnumerateViewConfigurationViews(instance, system_id, XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO, views_capacity, &views_count, views.data());
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get view configuration views.");
}
assert(views_count == 2); //OpenXR spec says it *must* be two views
size.x = views[0].recommendedImageRectWidth;
size.y = views[0].recommendedImageRectHeight;
std::cout << "Will create images of size " << size.x << "x" << size.y << "." << std::endl;
}
{ //swapchain creation
uint32_t format_capacity = 0;
//query needed format capacity:
if (XrResult res = xrEnumerateSwapchainFormats(session, 0, &format_capacity, nullptr);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to count swapchain formats: " + to_string(res));
}
//allocate enough space and get them:
std::vector< int64_t > formats(format_capacity, 0);
uint32_t format_count = 0;
if (XrResult res = xrEnumerateSwapchainFormats(session, format_capacity, &format_count, formats.data());
res != XR_SUCCESS) {
throw std::runtime_error("Failed to enumerate swapchain formats: " + to_string(res));
}
GLenum wanted_format = GL_SRGB8_ALPHA8;
std::string wanted_format_name = "GL_SRGB8_ALPHA8"; //for error/info messages
bool have_wanted_format = false;
std::cout << "Got " << format_count << " swapchain formats." << std::endl;
for (uint32_t f = 0; f < format_count; ++f) {
int64_t format = formats[f];
if (format == wanted_format) have_wanted_format = true;
std::cout << " [" << f << "]: ";
#define DO(fmt) if (format == fmt) { std::cout << #fmt; } else
DO(GL_RGB8)
DO(GL_RGBA8)
DO(GL_SRGB8)
DO(GL_SRGB8_ALPHA8)
DO(GL_RGBA16F)
DO(GL_RGBA32F)
DO(GL_DEPTH_COMPONENT16)
DO(GL_DEPTH_COMPONENT24)
DO(GL_DEPTH_COMPONENT32F)
{ std::cout << " as-of-yet untranslated enum 0x" << std::hex << format << std::dec; }
std::cout << std::endl;
#undef DO
}
if (!have_wanted_format) {
throw std::runtime_error(wanted_format_name + " was not among the preferred formats; this code expects it to be.");
} else {
std::cerr << "Chose " << wanted_format_name << " for swapchain format." << std::endl;
}
XrSwapchainCreateInfo create_info{XR_TYPE_SWAPCHAIN_CREATE_INFO};
create_info.createFlags = 0;
create_info.usageFlags = XR_SWAPCHAIN_USAGE_COLOR_ATTACHMENT_BIT | XR_SWAPCHAIN_USAGE_SAMPLED_BIT; //NOTE: USAGE_SAMPLED_BIT was used by the ovr sdk sample; not sure if this is actually needed
create_info.format = wanted_format;
create_info.sampleCount = 1;
create_info.width = size.x;
create_info.height = size.y;
create_info.faceCount = 1;
create_info.arraySize = 1;
create_info.mipCount = 1;
for (auto &view : views) {
if (XrResult res = xrCreateSwapchain(session, &create_info, &view.swapchain);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to create swapchain: " + to_string(res));
}
uint32_t chain_length = 0;
//fetch length:
if (XrResult res = xrEnumerateSwapchainImages(view.swapchain, 0, &chain_length, NULL);
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get swapchain length: " + to_string(res));
}
#ifdef __ANDROID__
std::vector< XrSwapchainImageOpenGLESKHR > images(chain_length, XrSwapchainImageOpenGLESKHR{XR_TYPE_SWAPCHAIN_IMAGE_OPENGL_ES_KHR});
#else //__ANDROID__
std::vector< XrSwapchainImageOpenGLKHR > images(chain_length, XrSwapchainImageOpenGLKHR{XR_TYPE_SWAPCHAIN_IMAGE_OPENGL_KHR});
#endif //__ANDROID__
//actually fetch image structures:
if (XrResult res = xrEnumerateSwapchainImages(view.swapchain, uint32_t(images.size()), &chain_length, reinterpret_cast< XrSwapchainImageBaseHeader * >(images.data()));
res != XR_SUCCESS) {
throw std::runtime_error("Failed to get swapchain images: " + to_string(res));
}
assert(chain_length == uint32_t(images.size())); //chain hasn't changed length
view.framebuffers.resize(images.size());
for (uint32_t i = 0; i < view.framebuffers.size(); ++i) {
view.framebuffers[i].color_tex = images[i].image;
//set texture sampling state: (ovr sdk sample does this; not sure if it is needed)
glBindTexture(GL_TEXTURE_2D, view.framebuffers[i].color_tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); //NEAREST might also be an option here
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, 0);
GL_ERRORS();
//allocate depth renderbuffer:
glGenRenderbuffers(1, &view.framebuffers[i].depth_rb);
glBindRenderbuffer(GL_RENDERBUFFER, view.framebuffers[i].depth_rb);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, size.x, size.y);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
GL_ERRORS();
//allocate framebuffer:
glGenFramebuffers(1, &view.framebuffers[i].fb);
glBindFramebuffer(GL_FRAMEBUFFER, view.framebuffers[i].fb);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, view.framebuffers[i].depth_rb);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, view.framebuffers[i].color_tex, 0);
GL_ERRORS();
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if (status != GL_FRAMEBUFFER_COMPLETE) {
#define DO(name) \
if (status == name) { throw std::runtime_error("Failed to create a complete framebuffer:" + std::string(#name)); } else
DO(GL_FRAMEBUFFER_UNDEFINED);
DO(GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT);
DO(GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT);
DO(GL_FRAMEBUFFER_UNSUPPORTED);
DO(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE);
#ifndef __ANDROID__
DO(GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER);
DO(GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER);
DO(GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS);
#endif
{
std::ostringstream str;
str << "0x" << std::hex << status;
throw std::runtime_error("Failed to create a complete framebuffer: unknown status " + str.str());
}
#undef DO
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
GL_ERRORS();
}
std::cout << "view[" << (&view - &views[0]) << "] has " << view.framebuffers.size() << " images in swapchain." << std::endl;
}
}
}
XR::~XR() {
std::cout << "--- shutting down OpenXR ---" << std::endl;
if (running) {
if (XrResult res = xrRequestExitSession(session);
res != XR_SUCCESS) {
std::cerr << "XR failed to xrRequestExitSession: " << to_string(res) << std::endl;
}
//wait a moment for session to stop running
for (uint32_t iter = 0; iter < 10; ++iter) {
poll_events();
if (!running) break;
std::this_thread::sleep_for(std::chrono::milliseconds(100));
}
if (running) {
std::cerr << "Waiting a fair bit of time, but session hasn't returned to idle yet." << std::endl;
}
}
for (auto &view : views) {
for (auto &framebuffer : view.framebuffers) {
if (framebuffer.fb != 0) {
glDeleteFramebuffers(1, &framebuffer.fb);
framebuffer.fb = 0;
}
if (framebuffer.depth_rb != 0) {
glDeleteRenderbuffers(1, &framebuffer.depth_rb);
framebuffer.depth_rb = 0;
}
//don't free color_tex -- xrDestroySwapchain should manage that
}
view.framebuffers.clear();
if (view.swapchain != XR_NULL_HANDLE) {
if (XrResult res = xrDestroySwapchain(view.swapchain);
res != XR_SUCCESS) {
std::cerr << "XR failed to destroy swapchain: " << to_string(res) << std::endl;
}
view.swapchain = XR_NULL_HANDLE;
}
}
if (stage != XR_NULL_HANDLE) {
std::cout << " destroying space..." << std::endl;
if (XrResult res = xrDestroySpace(stage);
res != XR_SUCCESS) {
std::cerr << "XR failed to destroy stage space: " << to_string(res) << std::endl;
}
stage = XR_NULL_HANDLE;
}
if (session != XR_NULL_HANDLE) {
std::cout << " destroying session..." << std::endl;
if (XrResult res = xrDestroySession(session);
res != XR_SUCCESS) {
std::cerr << "XR failed to destroy session: " << to_string(res) << std::endl;
}
session = XR_NULL_HANDLE;
}
//FOR SOME REASON... this hangs on SteamVR on linux. Not sure why. Grumble.
if (instance != XR_NULL_HANDLE) {
std::cout << " destroying instance..." << std::endl;
if (XrResult res = xrDestroyInstance(instance);
res != XR_SUCCESS) {
instance = XR_NULL_HANDLE;
std::cerr << "XR failed to destroy instance: " << to_string(res) << std::endl;
}
instance = XR_NULL_HANDLE;
}
}
std::string XR::to_string(XrResult result) const {
std::string ret;
bool use_adhoc = true;
if (instance) {
char buffer[XR_MAX_RESULT_STRING_SIZE];
XrResult res = xrResultToString(instance, result, buffer);
if (res == XR_SUCCESS) {
ret = buffer;
use_adhoc = false;
}
}
if (use_adhoc) {
//based on example in openxr_reflection.h:
#define XR_ENUM_CASE_STR(name, val) if (result == name) { ret = #name; } else
#define XR_ENUM_STR(enumType) \
XR_LIST_ENUM_##enumType(XR_ENUM_CASE_STR) \
{ ret = "Unknown [" + std::to_string(result) + "]"; }
XR_ENUM_STR(XrResult);
#undef XR_ENUM_CASE_STR
#undef XR_ENUM_STR
}
return ret;
}
void XR::poll_events() {
//read events:
while (true) {
XrEventDataBuffer event{XR_TYPE_EVENT_DATA_BUFFER};
//fill event structure:
if (XrResult res = xrPollEvent(instance, &event);
res == XR_EVENT_UNAVAILABLE) {
break;
} else if (res != XR_SUCCESS) {
std::cerr << "XR failed to poll event: " << to_string(res);
break;
}
//interpret event structure:
if (event.type == XR_TYPE_EVENT_DATA_EVENTS_LOST) {
XrEventDataEventsLost const &event_ = *reinterpret_cast< XrEventDataEventsLost * >(&event);
std::cout << "INFO: Lost " << event_.lostEventCount << " events." << std::endl;
} else if (event.type == XR_TYPE_EVENT_DATA_INSTANCE_LOSS_PENDING) {
XrEventDataInstanceLossPending const &event_ = *reinterpret_cast< XrEventDataInstanceLossPending * >(&event);
std::cout << "INFO: Instance loss pending at " << event_.lossTime << "." << std::endl;
} else if (event.type == XR_TYPE_EVENT_DATA_INTERACTION_PROFILE_CHANGED) {
XrEventDataInteractionProfileChanged const &event_ = *reinterpret_cast< XrEventDataInteractionProfileChanged * >(&event);
std::cout << "INFO: Interaction profile changed in " << (event_.session == session ? "this session" : "some other session (?!)") << "." << std::endl;
} else if (event.type == XR_TYPE_EVENT_DATA_REFERENCE_SPACE_CHANGE_PENDING) {
XrEventDataReferenceSpaceChangePending const &event_ = *reinterpret_cast< XrEventDataReferenceSpaceChangePending * >(&event);
std::cout << "INFO: reference space changing at " << event_.changeTime << "." << std::endl;
} else if (event.type == XR_TYPE_EVENT_DATA_SESSION_STATE_CHANGED) {
XrEventDataSessionStateChanged const &event_ = *reinterpret_cast< XrEventDataSessionStateChanged * >(&event);
std::cout << "INFO: session state changed at " << event_.time << " to ";
#define XR_ENUM_CASE_STR(name, val) if (event_.state == name) { std::cout << #name; } else
#define XR_ENUM_STR(enumType) \
XR_LIST_ENUM_##enumType(XR_ENUM_CASE_STR) \
{ std::cout << "unknown [" << std::to_string(event_.state) << "]"; }
XR_ENUM_STR(XrSessionState);
#undef XR_ENUM_CASE_STR
#undef XR_ENUM_STR
std::cout << "." << std::endl;
session_state = event_.state;
if (session_state == XR_SESSION_STATE_READY) {
XrSessionBeginInfo begin_info{XR_TYPE_SESSION_BEGIN_INFO};
begin_info.primaryViewConfigurationType = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO;
if (XrResult res = xrBeginSession(session, &begin_info);
res != XR_SUCCESS) {
std::cerr << "Error reported beginning session: " << to_string(res) << std::endl;
}
running = true;
} else if (session_state == XR_SESSION_STATE_STOPPING) {
if (XrResult res = xrEndSession(session);
res != XR_SUCCESS) {
std::cerr << "Error reported ending session: " << to_string(res) << std::endl;
}
running = false;
}
} else {
std::cerr << "WARNING: ignoring unrecognized event type " << event.type << "." << std::endl;
}
}
}
void XR::wait_frame() {
XrFrameState frame_state{XR_TYPE_FRAME_STATE};
if (XrResult res = xrWaitFrame(session, NULL /* XrWaitFrameInfo, is empty as of 1.0 */, &frame_state);
res != XR_SUCCESS) {
std::cerr << "Failed to xrWaitFrame: " << to_string(res) << std::endl;
}
next_frame.display_time = frame_state.predictedDisplayTime;
next_frame.should_render = (frame_state.shouldRender == XR_TRUE);
}
void XR::begin_frame() {
if (XrResult res = xrBeginFrame(session, NULL /* XrBeginFrameInfo, is empty as of 1.0 */);
res != XR_SUCCESS) {
std::cerr << "Failed to xrBeginFrame: " << to_string(res) << std::endl;
}
//set up current image to render into:
for (auto &view : views) {
//get the index of the next image to render into:
uint32_t index = 0;
if (XrResult res = xrAcquireSwapchainImage(view.swapchain, NULL /* XrSwapchainImageAcquireInfo, empty as of 1.0 */, &index);
res != XR_SUCCESS) {
std::cerr << "Failed to xrAcquireSwapchainImage: " << to_string(res) << std::endl;
}
//wait for that image to be ready for rendering:
XrSwapchainImageWaitInfo wait_info{XR_TYPE_SWAPCHAIN_IMAGE_WAIT_INFO};
wait_info.timeout = XR_INFINITE_DURATION;
if (XrResult res = xrWaitSwapchainImage(view.swapchain, &wait_info);
res != XR_SUCCESS) {
std::cerr << "Failed to xrWaitSwapchainImage: " << to_string(res) << std::endl;
}
//update the current_framebuffer pointer appropriately:
view.current_framebuffer = &view.framebuffers.at(index);
}
//update views with current transform in stage space:
XrViewLocateInfo info{XR_TYPE_VIEW_LOCATE_INFO};
info.viewConfigurationType = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO;
info.displayTime = next_frame.display_time;
info.space = stage;
XrViewState view_state{XR_TYPE_VIEW_STATE};
std::array< XrView, 2 > located_views;
located_views.fill(XrView{XR_TYPE_VIEW});
uint32_t view_capacity = located_views.size();
uint32_t view_count = 0;
if (XrResult res = xrLocateViews(session, &info, &view_state, view_capacity, &view_count, located_views.data());
res != XR_SUCCESS) {
std::cerr << "Failed to xrLocateViews: " << to_string(res) << std::endl;
}
if (view_count != 2) {
std::cerr << "ERROR: Somehow didn't get exactly two views located?!" << std::endl;
return;
}
for (uint32_t v = 0; v < views.size(); ++v) {
if (view_state.viewStateFlags & XR_VIEW_STATE_ORIENTATION_VALID_BIT) {
views[v].pose.orientation = located_views[v].pose.orientation;
} else {
views[v].pose.orientation = XrQuaternionf{0.0f, 0.0f, 0.0f, 1.0f};
}
if (view_state.viewStateFlags & XR_VIEW_STATE_POSITION_VALID_BIT) {
views[v].pose.position = located_views[v].pose.position;
} else {
views[v].pose.position = XrVector3f{0.0f, 0.0f, 0.0f};
}
views[v].fov = located_views[v].fov;
}
}
void XR::end_frame() {
//done rendering: release swapchain images
for (auto &view : views) {
if (XrResult res = xrReleaseSwapchainImage(view.swapchain, NULL /* XrSwapchainImageReleaseInfo, empty as of 1.0 */);
res != XR_SUCCESS) {
std::cerr << "Failed to xrReleaseSwapchainImage: " << to_string(res) << std::endl;
}
view.current_framebuffer = nullptr;
}
//tell compositor about rendered images:
std::array< XrCompositionLayerProjectionView, 2 > projection_views;
projection_views.fill(XrCompositionLayerProjectionView{XR_TYPE_COMPOSITION_LAYER_PROJECTION_VIEW});
static_assert(std::tuple_size< decltype(views) >::value == std::tuple_size< decltype(projection_views) >::value, "Correct number of eyes.");
for (uint32_t v = 0; v < projection_views.size(); ++v) {
projection_views[v].pose = views[v].pose;
projection_views[v].fov = views[v].fov;
projection_views[v].subImage.swapchain = views[v].swapchain;
projection_views[v].subImage.imageRect.offset.x = 0;
projection_views[v].subImage.imageRect.offset.y = 0;
projection_views[v].subImage.imageRect.extent.width = size.x;
projection_views[v].subImage.imageRect.extent.height = size.y;
projection_views[v].subImage.imageArrayIndex = 0;
}
XrCompositionLayerProjection layer{XR_TYPE_COMPOSITION_LAYER_PROJECTION};
layer.layerFlags = XR_COMPOSITION_LAYER_CORRECT_CHROMATIC_ABERRATION_BIT //note: "planned for deprecation"
//| XR_COMPOSITION_LAYER_BLEND_TEXTURE_SOURCE_ALPHA_BIT //probably not needed for OPAQUE mode?
;
layer.space = stage;
layer.viewCount = projection_views.size();
layer.views = projection_views.data();
std::array< XrCompositionLayerBaseHeader *, 1 > layers;
layers[0] = reinterpret_cast< XrCompositionLayerBaseHeader * >(&layer);
XrFrameEndInfo info{XR_TYPE_FRAME_END_INFO};
info.displayTime = next_frame.display_time;
info.environmentBlendMode = XR_ENVIRONMENT_BLEND_MODE_OPAQUE;
info.layerCount = layers.size();
info.layers = layers.data();
if (XrResult res = xrEndFrame(session, &info);
res != XR_SUCCESS) {
std::cerr << "Failed to xrEndFrame: " << to_string(res) << std::endl;
}
}