Upstream: GL implementation on Android

ui/gfx/gl/gl_implementation_android.cc

+// Copyright (c) 2011 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 "base/base_paths.h"
+#include "base/command_line.h"
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/native_library.h"
+#include "base/path_service.h"
+#include "ui/gfx/gl/gl_bindings.h"
+#include "ui/gfx/gl/gl_implementation.h"
+
+namespace gfx {
+
+namespace {
+
+void GL_BINDING_CALL MarshalClearDepthToClearDepthf(GLclampd depth) {
+  glClearDepthf(static_cast<GLclampf>(depth));
+}
+
+void GL_BINDING_CALL MarshalDepthRangeToDepthRangef(GLclampd z_near,
+                                                    GLclampd z_far) {
+  glDepthRangef(static_cast<GLclampf>(z_near), static_cast<GLclampf>(z_far));
+}
+
+base::NativeLibrary LoadLibrary(const FilePath& filename) {
+  std::string error;
+  base::NativeLibrary library = base::LoadNativeLibrary(filename, &error);
+  if (!library) {
+    VLOG(1) << "Failed to load " << filename.MaybeAsASCII() << ": " << error;
+    return NULL;
+  }
+  return library;
+}
+
+base::NativeLibrary LoadLibrary(const char* filename) {
+  return LoadLibrary(FilePath(filename));
+}
+
+}  // namespace anonymous
+
+bool InitializeGLBindings(GLImplementation implementation) {
+  // Prevent reinitialization with a different implementation. Once the gpu
+  // unit tests have initialized with kGLImplementationMock, we don't want to
+  // later switch to another GL implementation.
+  if (GetGLImplementation() != kGLImplementationNone)
+    return true;
+
+  switch (implementation) {
+    case kGLImplementationEGLGLES2: {
+      base::NativeLibrary gles_library = LoadLibrary("libGLESv2.so");
+      if (!gles_library)
+        return false;
+      base::NativeLibrary egl_library = LoadLibrary("libEGL.so");
+      if (!egl_library)
+        return false;
+
+      // Note: Android is a GLES2 platform so no EXT or ARB entry points are
+      // used by Chromium on such platforms. However, gl_bindings_autogen_gl.cc
+      // code looks up the EXT entry points with eglGetProcAddress(), comparing
+      // the resulting function pointers against NULL to decide whether it
+      // should fall back to the non-EXT versions of these functions.
+      // However, this is wrong as eglGetProcAddress() is not guaranteed to
+      // return NULL if an extension is not supported. On Android, the
+      // end-result is that we end up with the wrong function pointers for
+      // many GL functions and the rendering is broken.
+      // TODO(andreip): Fix this properly by modifying the generate_bindings.py
+      // python script that generates the lookup code so that we give it two
+      // lists: one of function names to look up on desktop GL and one for
+      // those to look up on GLES2.
+      // see, http://code.google.com/p/chromium/issues/detail?id=105011
+      AddGLNativeLibrary(egl_library);
+      AddGLNativeLibrary(gles_library);
+      SetGLImplementation(kGLImplementationEGLGLES2);
+
+      InitializeGLBindingsGL();
+      InitializeGLBindingsEGL();
+
+      // These two functions take single precision float rather than double
+      // precision float parameters in GLES.
+      ::gfx::g_glClearDepth = MarshalClearDepthToClearDepthf;
+      ::gfx::g_glDepthRange = MarshalDepthRangeToDepthRangef;
+      break;
+    }
+    case kGLImplementationMockGL: {
+      SetGLGetProcAddressProc(GetMockGLProcAddress);
+      SetGLImplementation(kGLImplementationMockGL);
+      InitializeGLBindingsGL();
+      break;
+    }
+    default:
+      NOTIMPLEMENTED() << "InitializeGLBindings on Android";
+      return false;
+  }
+
+  return true;
+}
+
+void InitializeDebugGLBindings() {
+}
+
+}  // namespace gfx