add static function isVBOSupported to OpenGLBuffer to check for the GL_ARB_vertex_buffer_object extension

src/Gui/GLBuffer.cpp

@@ -41,6 +41,8 @@
 #include <Inventor/errors/SoDebugError.h>
 #include <Inventor/misc/SoContextHandler.h>
 
+#include <string>
+
 #include "GLBuffer.h"
 
 using namespace Gui;
@@ -63,6 +65,21 @@ OpenGLBuffer::~OpenGLBuffer()
     destroy();
 }
 
+/*!
+ * \brief OpenGLBuffer::isVBOSupported returns if the OpenGL driver
+ * supports the VBO extension.
+ * When calling this function there must be a current OpenGL context.
+ * \return
+ */
+bool OpenGLBuffer::isVBOSupported()
+{
+    const GLubyte * str = glGetString(GL_EXTENSIONS);
+    if (!str)
+        return false;
+    std::string ext = reinterpret_cast<const char*>(str);
+    return (ext.find("GL_ARB_vertex_buffer_object") != std::string::npos);
+}
+
 void OpenGLBuffer::setCurrentContext(uint32_t ctx)
 {
     currentContext = ctx;
@@ -74,6 +91,9 @@ bool OpenGLBuffer::create()
     if (bufferId > 0)
         return true;
 
+    if (!cc_glglue_has_vertex_buffer_object(glue))
+        return false;
+
     cc_glglue_glGenBuffers(glue, 1, &bufferId);
     context = currentContext;
     return true;

src/Gui/GLBuffer.h

@@ -34,6 +34,8 @@ public:
     OpenGLBuffer(GLenum type);
     ~OpenGLBuffer();
 
+    static bool isVBOSupported();
+
     void setCurrentContext(uint32_t ctx);
     bool create();
     bool isCreated() const;

src/Mod/Mesh/Gui/SoFCIndexedFaceSet.cpp

@@ -106,8 +106,11 @@ bool MeshRenderer::Private::canRenderGLArray(SoGLRenderAction *action) const
     static bool init = false;
     static bool vboAvailable = false;
     if (!init) {
-        std::string ext = (const char*)(glGetString(GL_EXTENSIONS));
-        vboAvailable = (ext.find("GL_ARB_vertex_buffer_object") != std::string::npos);
+        vboAvailable = Gui::OpenGLBuffer::isVBOSupported();
+        if (!vboAvailable) {
+            SoDebugError::postInfo("MeshRenderer",
+                                   "GL_ARB_vertex_buffer_object extension not supported");
+        }
         init = true;
     }
 
@@ -483,7 +486,7 @@ void SoFCIndexedFaceSet::GLRender(SoGLRenderAction *action)
 
     // get the VBO status of the viewer
     SbBool useVBO = true;
-    //Gui::SoGLVBOActivatedElement::get(state, useVBO);
+    Gui::SoGLVBOActivatedElement::get(state, useVBO);
 
     // Check for a matching OpenGL context
     if (!render.canRenderGLArray(action))