From fa4a6d431b75eb710f6c50f6f367604850441ede Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Thu, 2 May 2019 17:24:57 +0100
Subject: [PATCH] Only use modern extension query on new contexts. Refs #1359

* On mac on legacy contexts (GL2.1) glGetStringi will understandably fail
  completely, so we can't expect to be able to use modern enumeration of
  extensions on the assumption that it's really a compatibility context.
---
 renderdoc/driver/gl/gl_common.cpp | 45 +++++++++++++++++++++----------
 renderdoc/driver/gl/gl_common.h   |  1 +
 renderdoc/driver/gl/gl_driver.cpp |  8 +++++-
 3 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/renderdoc/driver/gl/gl_common.cpp b/renderdoc/driver/gl/gl_common.cpp
index a36ec3442..4f1eadcd7 100644
--- a/renderdoc/driver/gl/gl_common.cpp
+++ b/renderdoc/driver/gl/gl_common.cpp
@@ -378,14 +378,8 @@ static void CheckExtFromString(const char *ext)
   }
 }
 
-void FetchEnabledExtensions()
+void GetContextVersion(bool &ctxGLES, int &ctxVersion)
 {
-  GLint numExts = 0;
-  if(GL.glGetIntegerv)
-    GL.glGetIntegerv(eGL_NUM_EXTENSIONS, &numExts);
-
-  RDCEraseEl(HasExt);
-
   if(GL.glGetString)
   {
     const char *version = (const char *)GL.glGetString(eGL_VERSION);
@@ -395,15 +389,19 @@ void FetchEnabledExtensions()
     //   "OpenGL ES N.M vendor-specific information"
     if(strncmp(version, "OpenGL ES", 9) == 0)
     {
-      IsGLES = true;
+      ctxGLES = true;
 
       int mj = int(version[10] - '0');
       int mn = int(version[12] - '0');
-      GLCoreVersion = RDCMAX(GLCoreVersion, mj * 10 + mn);
+      ctxVersion = mj * 10 + mn;
     }
     else
     {
-      IsGLES = false;
+      ctxGLES = false;
+
+      int mj = int(version[0] - '0');
+      int mn = int(version[1] - '0');
+      ctxVersion = mj * 10 + mn;
     }
   }
 
@@ -413,14 +411,33 @@ void FetchEnabledExtensions()
     GL.glGetIntegerv(eGL_MAJOR_VERSION, &mj);
     GL.glGetIntegerv(eGL_MINOR_VERSION, &mn);
 
-    GLCoreVersion = RDCMAX(GLCoreVersion, mj * 10 + mn);
+    if(mj > 0)
+      ctxVersion = mj * 10 + mn;
   }
+}
+
+void FetchEnabledExtensions()
+{
+  RDCEraseEl(HasExt);
+
+  int ctxVersion = 0;
+  bool ctxGLES = false;
+  GetContextVersion(ctxGLES, ctxVersion);
+
+  GLCoreVersion = RDCMAX(GLCoreVersion, ctxVersion);
+  IsGLES = ctxGLES;
 
   RDCLOG("Checking enabled extensions, running as %s %d.%d", IsGLES ? "OpenGL ES" : "OpenGL",
-         (GLCoreVersion / 10), (GLCoreVersion % 10));
+         (ctxVersion / 10), (ctxVersion % 10));
 
-  if(GL.glGetStringi)
+  // only use glGetStringi on 3.0 contexts and above (ES and GL), even if we have the function
+  // pointer
+  if(GL.glGetStringi && ctxVersion >= 30)
   {
+    GLint numExts = 0;
+    if(GL.glGetIntegerv)
+      GL.glGetIntegerv(eGL_NUM_EXTENSIONS, &numExts);
+
     for(int i = 0; i < numExts; i++)
     {
       const char *ext = (const char *)GL.glGetStringi(eGL_EXTENSIONS, (GLuint)i);
@@ -428,7 +445,7 @@ void FetchEnabledExtensions()
       CheckExtFromString(ext);
     }
   }
-  else if(GL.glGetString && IsGLES && GLCoreVersion < 30)
+  else if(GL.glGetString)
   {
     std::string extstr = (const char *)GL.glGetString(eGL_EXTENSIONS);
 
diff --git a/renderdoc/driver/gl/gl_common.h b/renderdoc/driver/gl/gl_common.h
index da8b1d4a8..28927863d 100644
--- a/renderdoc/driver/gl/gl_common.h
+++ b/renderdoc/driver/gl/gl_common.h
@@ -827,6 +827,7 @@ extern bool VendorCheck[VendorCheck_Count];
 
 // fills out the extension supported array and the version-specific checks above
 void DoVendorChecks(GLPlatform &platform, GLWindowingData context);
+void GetContextVersion(bool &ctxGLES, int &ctxVersion);
 void FetchEnabledExtensions();
 
 // verify that we got a replay context that we can work with
diff --git a/renderdoc/driver/gl/gl_driver.cpp b/renderdoc/driver/gl/gl_driver.cpp
index b907caf9c..ad71cc3f5 100644
--- a/renderdoc/driver/gl/gl_driver.cpp
+++ b/renderdoc/driver/gl/gl_driver.cpp
@@ -1197,7 +1197,13 @@ void WrappedOpenGL::ActivateContext(GLWindowingData winData)
 
       vector<string> implExts;
 
-      if(GL.glGetIntegerv && GL.glGetStringi)
+      int ctxVersion = 0;
+      bool ctxGLES = false;
+      GetContextVersion(ctxGLES, ctxVersion);
+
+      // only use glGetStringi on 3.0 contexts and above (ES and GL), even if we have the function
+      // pointer
+      if(GL.glGetIntegerv && GL.glGetStringi && ctxVersion >= 30)
       {
         GLuint numExts = 0;
         GL.glGetIntegerv(eGL_NUM_EXTENSIONS, (GLint *)&numExts);