From 981ed25daca997251855f8f84e6523c25fc7eecd Mon Sep 17 00:00:00 2001
From: Christoph Haag <christoph.haag@collabora.com>
Date: Wed, 13 Jan 2021 13:32:34 +0100
Subject: [PATCH] call xrGetOpenGLGraphicsRequirementsKHR on linux too

This call is required per the spec.
---
 apps/openmw/mwvr/openxrplatform.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/apps/openmw/mwvr/openxrplatform.cpp b/apps/openmw/mwvr/openxrplatform.cpp
index 97b66db03..1caec08b5 100644
--- a/apps/openmw/mwvr/openxrplatform.cpp
+++ b/apps/openmw/mwvr/openxrplatform.cpp
@@ -470,7 +470,20 @@ namespace MWVR
             throw std::logic_error("Enum value not implemented");
         }
 #elif __linux__
-        { // Create Session
+        {
+            // Get system requirements
+            PFN_xrGetOpenGLGraphicsRequirementsKHR p_getRequirements = nullptr;
+            xrGetInstanceProcAddr(instance, "xrGetOpenGLGraphicsRequirementsKHR", reinterpret_cast<PFN_xrVoidFunction*>(&p_getRequirements));
+            XrGraphicsRequirementsOpenGLKHR requirements{ XR_TYPE_GRAPHICS_REQUIREMENTS_OPENGL_KHR };
+            CHECK_XRCMD(p_getRequirements(instance, systemId, &requirements));
+
+            // TODO: Actually get system version
+            const XrVersion systemApiVersion = XR_MAKE_VERSION(4, 6, 0);
+            if (requirements.minApiVersionSupported > systemApiVersion) {
+                std::cout << "Runtime does not support desired Graphics API and/or version" << std::endl;
+            }
+
+            // Create Session
             Display* xDisplay = XOpenDisplay(NULL);
             GLXContext glxContext = glXGetCurrentContext();
             GLXDrawable glxDrawable = glXGetCurrentDrawable();