1 files changed, 86 insertions, 0 deletions
diff --git a/gfx/gl/gl_context.cc b/gfx/gl/gl_context.cc
new file mode 100644
index 0000000..cf9b111
--- /dev/null
+++ b/gfx/gl/gl_context.cc
@@ -0,0 +1,86 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <GL/glew.h>
+
+#include "gfx/gl/gl_context.h"
+#include "base/logging.h"
+
+namespace gfx {
+
+// GLEW initialization is extremely expensive because it looks up
+// hundreds of function pointers. Realistically we are not going to
+// switch between GL implementations on the fly, so for the time being
+// we only do the context-dependent GLEW initialization once.
+bool InitializeGLEW() {
+#if defined(UNIT_TEST)
+  return true;
+#else
+  static bool initialized = false;
+  if (initialized)
+    return true;
+
+  // Initializes context-dependent parts of GLEW.
+  if (glewInit() != GLEW_OK) {
+    LOG(ERROR) << "GLEW failed initialization";
+    return false;
+  }
+
+  // Check to see that we can use the OpenGL vertex attribute APIs
+  // TODO(petersont):  Return false if this check fails, but because some
+  // Intel hardware does not support OpenGL 2.0, yet does support all of the
+  // extensions we require, we only log an error.  A future CL should change
+  // this check to ensure that all of the extension strings we require are
+  // present.
+  if (!GLEW_VERSION_2_0) {
+    DLOG(ERROR) << "GL drivers do not have OpenGL 2.0 functionality.";
+  }
+
+  // Check for necessary extensions.
+  bool extensions_found = true;
+  if (!GLEW_ARB_vertex_buffer_object) {
+    // NOTE: Linux NVidia drivers claim to support OpenGL 2.0 when using
+    // indirect rendering (e.g. remote X), but it is actually lying. The
+    // ARB_vertex_buffer_object functions silently no-op (!) when using
+    // indirect rendering, leading to crashes. Fortunately, in that case, the
+    // driver claims to not support ARB_vertex_buffer_object, so fail in that
+    // case.
+    DLOG(ERROR) << "GL drivers do not support vertex buffer objects.";
+    extensions_found = false;
+  }
+  if (!GLEW_EXT_framebuffer_object) {
+    DLOG(ERROR) << "GL drivers do not support framebuffer objects.";
+    extensions_found = false;
+  }
+  if (!GLEW_VERSION_2_0 && !GLEW_EXT_stencil_two_side) {
+    DLOG(ERROR) << "Two sided stencil extension missing.";
+    extensions_found = false;
+  }
+  if (!GLEW_VERSION_1_4 && !GLEW_EXT_blend_func_separate) {
+    DLOG(ERROR) <<"Separate blend func extension missing.";
+    extensions_found = false;
+  }
+  if (!GLEW_VERSION_2_0 && !GLEW_EXT_blend_equation_separate) {
+    DLOG(ERROR) << "Separate blend function extension missing.";
+    extensions_found = false;
+  }
+  if (!extensions_found)
+    return false;
+
+  initialized = true;
+  return true;
+#endif
+}
+
+bool GLContext::InitializeCommon() {
+  if (!MakeCurrent())
+    return false;
+
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+  if (glGetError() != GL_NO_ERROR)
+    return false;
+
+  return true;
+}
+}  // namespace gfx