Platform: no-forward-compatible-core-context also on Intel/Windows.

Detected in WindowlessWglApplication, added it to both Sdl2Application
and WindowlessWglApplication. Renamed the workaround to reflect that it
is for all three major vendors.

src/Magnum/Implementation/driverSpecific.cpp

@@ -35,10 +35,13 @@ namespace Magnum {
 namespace {
     std::vector<std::string> KnownWorkarounds{
         #ifndef MAGNUM_TARGET_GLES
+        #ifndef CORRADE_TARGET_APPLE
         /* Creating core context with specific version on AMD and NV
-           proprietary drivers causes the context to be forced to given
-           version instead of selecting latest available version */
-        "amd-nv-no-forward-compatible-core-context",
+           proprietary drivers on Linux/Windows and Intel drivers on Windows
+           causes the context to be forced to given version instead of
+           selecting latest available version */
+        "no-forward-compatible-core-context",
+        #endif
 
         #ifdef CORRADE_TARGET_WINDOWS
         /* On Windows Intel drivers ARB_shading_language_420pack is exposed in

src/Magnum/Platform/Sdl2Application.cpp

@@ -186,6 +186,9 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
        version to the one specified, which is completely useless behavior. */
     #ifndef CORRADE_TARGET_APPLE
     constexpr static const char nvidiaVendorString[] = "NVIDIA Corporation";
+    #ifdef CORRADE_TARGET_WINDOWS
+    constexpr static const char intelVendorString[] = "Intel";
+    #endif
     constexpr static const char amdVendorString[] = "ATI Technologies Inc.";
     const char* vendorString;
     #endif
@@ -194,8 +197,11 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
         /* Sorry about the UGLY code, HOPEFULLY THERE WON'T BE MORE WORKAROUNDS */
         || (vendorString = reinterpret_cast<const char*>(glGetString(GL_VENDOR)),
         (std::strncmp(vendorString, nvidiaVendorString, sizeof(nvidiaVendorString)) == 0 ||
+         #ifdef CORRADE_TARGET_WINDOWS
+         std::strncmp(vendorString, intelVendorString, sizeof(intelVendorString)) == 0 ||
+         #endif
          std::strncmp(vendorString, amdVendorString, sizeof(amdVendorString)) == 0)
-         && !_context->isDriverWorkaroundDisabled("amd-nv-no-forward-compatible-core-context"))
+         && !_context->isDriverWorkaroundDisabled("no-forward-compatible-core-context"))
         #endif
     )) {
         /* Don't print any warning when doing the NV workaround, because the

src/Magnum/Platform/WindowlessGlxApplication.cpp

@@ -103,9 +103,9 @@ WindowlessGlxContext::WindowlessGlxContext(const WindowlessGlxContext::Configura
         _context = glXCreateContextAttribsARB(_display, configs[0], nullptr, True, fallbackContextAttributes);
 
     /* Fall back to (forward compatible) GL 2.1 if we are on binary NVidia/AMD
-       drivers on Linux/Windows. Instead of creating forward-compatible context
-       with highest available version, they force the version to the one
-       specified, which is completely useless behavior. */
+       drivers on Linux. Instead of creating forward-compatible context with
+       highest available version, they force the version to the one specified,
+       which is completely useless behavior. */
     } else {
         /* We need to make the context current to read out vendor string, so
            save the previous values so we can safely revert back without
@@ -125,7 +125,7 @@ WindowlessGlxContext::WindowlessGlxContext(const WindowlessGlxContext::Configura
         const char* const vendorString = reinterpret_cast<const char*>(glGetString(GL_VENDOR));
         if((std::strncmp(vendorString, nvidiaVendorString, sizeof(nvidiaVendorString)) == 0 ||
             std::strncmp(vendorString, amdVendorString, sizeof(amdVendorString)) == 0) &&
-            (!magnumContext || !magnumContext->isDriverWorkaroundDisabled("amd-nv-no-forward-compatible-core-context")))
+            (!magnumContext || !magnumContext->isDriverWorkaroundDisabled("no-forward-compatible-core-context")))
         {
             /* Destroy the core context and create a compatibility one */
             glXDestroyContext(_display, _context);

src/Magnum/Platform/WindowlessWglApplication.cpp

@@ -138,10 +138,10 @@ WindowlessWglContext::WindowlessWglContext(const Configuration& configuration, C
         };
         _context = wglCreateContextAttribsARB(_deviceContext, nullptr, fallbackContextAttributes);
 
-    /* Fall back to (forward compatible) GL 2.1 if we are on binary NVidia/AMD
-       drivers on Linux/Windows. Instead of creating forward-compatible context
-       with highest available version, they force the version to the one
-       specified, which is completely useless behavior. */
+    /* Fall back to (forward compatible) GL 2.1 if we are on binary
+       NVidia/AMD/Intel drivers on Windows. Instead of creating forward-compatible
+       context with highest available version, they force the version to the
+       one specified, which is completely useless behavior. */
     } else {
         /* We need to make the context current to read out vendor string */
         if(!wglMakeCurrent(_deviceContext, _context)) {
@@ -157,11 +157,13 @@ WindowlessWglContext::WindowlessWglContext(const Configuration& configuration, C
         /* The workaround check is the last so it doesn't appear in workaround
            list on unrelated drivers */
         constexpr static const char nvidiaVendorString[] = "NVIDIA Corporation";
+        constexpr static const char intelVendorString[] = "Intel";
         constexpr static const char amdVendorString[] = "ATI Technologies Inc.";
         const char* const vendorString = reinterpret_cast<const char*>(glGetString(GL_VENDOR));
         if((std::strncmp(vendorString, nvidiaVendorString, sizeof(nvidiaVendorString)) == 0 ||
+            std::strncmp(vendorString, intelVendorString, sizeof(intelVendorString)) == 0 ||
             std::strncmp(vendorString, amdVendorString, sizeof(amdVendorString)) == 0) &&
-            (!magnumContext || !magnumContext->isDriverWorkaroundDisabled("amd-nv-no-forward-compatible-core-context")))
+            (!magnumContext || !magnumContext->isDriverWorkaroundDisabled("no-forward-compatible-core-context")))
         {
             /* Destroy the core context and create a compatibility one */
             wglDeleteContext(_context);

src/Magnum/Platform/magnum-info.cpp

@@ -115,7 +115,7 @@ Using optional features:
     GL_ARB_invalidate_subdata
     ...
 Using driver workarounds:
-    amd-nv-no-forward-compatible-core-context
+    no-forward-compatible-core-context
     no-layout-qualifiers-on-old-glsl
 Context flags:
 Supported GLSL versions: