TESTING: Add DGL_USE_OPENGL3 macro

dgl/Makefile

@@ -13,6 +13,10 @@ BUILD_CXX_FLAGS += $(DGL_FLAGS) -I. -Isrc -DDONT_SET_USING_DGL_NAMESPACE -Wno-un
 BUILD_CXX_FLAGS += -Isrc/pugl-upstream/include
 LINK_FLAGS      += $(DGL_LIBS)
 
+ifeq ($(USE_OPENGL3),true)
+BUILD_CXX_FLAGS += -DDGL_USE_OPENGL3
+endif
+
 # TODO fix these after pugl-upstream is done
 BUILD_CXX_FLAGS += -Wno-attributes -Wno-extra -Wno-missing-field-initializers
 ifneq ($(MACOS),true)

dgl/src/WindowPrivateData.cpp

@@ -234,6 +234,10 @@ void Window::PrivateData::initPre(const uint width, const uint height, const boo
     puglSetViewHint(view, PUGL_IGNORE_KEY_REPEAT, PUGL_FALSE);
     puglSetViewHint(view, PUGL_DEPTH_BITS, 16);
     puglSetViewHint(view, PUGL_STENCIL_BITS, 8);
+#ifdef DGL_USE_OPENGL3
+    puglSetViewHint(view, PUGL_USE_COMPAT_PROFILE, PUGL_FALSE);
+    puglSetViewHint(view, PUGL_CONTEXT_VERSION_MAJOR, 3);
+#endif
     // PUGL_SAMPLES ??
     puglSetEventFunc(view, puglEventCallback);
 }