GGL library is a variant of the WGL, EGL and PGL libraries.

It is used to create and destroy OpenGL contexts and make them current.
TEST=none
BUG=none

Review URL: http://codereview.chromium.org/661043

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@40940 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 280 insertions, 0 deletions

diff --git a/chrome/renderer/ggl/ggl.cc b/chrome/renderer/ggl/ggl.cc
new file mode 100644
index 0000000..6b5fbc2
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+++ b/chrome/renderer/ggl/ggl.cc
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+// Copyright (c) 2010 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 "build/build_config.h"
+
+#include "base/ref_counted.h"
+#include "base/singleton.h"
+#include "base/thread_local.h"
+#include "chrome/renderer/command_buffer_proxy.h"
+#include "chrome/renderer/ggl/ggl.h"
+#include "chrome/renderer/gpu_channel_host.h"
+#include "chrome/renderer/render_widget.h"
+#include "gpu/command_buffer/client/gles2_cmd_helper.h"
+#include "gpu/command_buffer/client/gles2_implementation.h"
+#include "gpu/command_buffer/client/gles2_lib.h"
+#include "gpu/command_buffer/common/constants.h"
+#include "ipc/ipc_channel_handle.h"
+
+namespace ggl {
+
+#if defined(ENABLE_GPU)
+
+namespace {
+
+const int32 kCommandBufferSize = 1024 * 1024;
+const int32 kTransferBufferSize = 1024 * 1024;
+
+base::ThreadLocalPointer<Context> g_current_context;
+
+// Singleton used to initialize and terminate the gles2 library.
+class GLES2Initializer {
+ public:
+  GLES2Initializer() {
+    gles2::Initialize();
+  }
+
+  ~GLES2Initializer() {
+    gles2::Terminate();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(GLES2Initializer);
+};
+}  // namespace anonymous
+
+// Manages a GL context.
+class Context {
+ public:
+  Context();
+  ~Context();
+
+  // Initialize a GGL context that can be used in association with a a GPU
+  // channel acquired from a RenderWidget or RenderView.
+  bool Initialize(GpuChannelHost* channel);
+
+  // Destroy all resources associated with the GGL context.
+  void Destroy();
+
+  // Make a GGL context current for the calling thread.
+  static bool MakeCurrent(Context* context);
+
+  // Display all content rendered since last call to SwapBuffers.
+  // TODO(apatrick): support rendering to browser window. This function is
+  // not useful at this point.
+  bool SwapBuffers();
+
+  // Get the current error code.
+  Error GetError();
+
+ private:
+  scoped_refptr<GpuChannelHost> channel_;
+  CommandBufferProxy* command_buffer_;
+  gpu::gles2::GLES2CmdHelper* gles2_helper_;
+  int32 transfer_buffer_id_;
+  gpu::gles2::GLES2Implementation* gles2_implementation_;
+
+  DISALLOW_COPY_AND_ASSIGN(Context);
+};
+
+Context::Context()
+    : channel_(NULL),
+      command_buffer_(NULL),
+      gles2_helper_(NULL),
+      transfer_buffer_id_(0),
+      gles2_implementation_(NULL) {
+}
+
+Context::~Context() {
+  Destroy();
+}
+
+bool Context::Initialize(GpuChannelHost* channel) {
+  DCHECK(channel);
+
+  if (!channel->ready())
+    return false;
+
+  channel_ = channel;
+
+  // Ensure the gles2 library is initialized first in a thread safe way.
+  Singleton<GLES2Initializer>::get();
+
+  // Create a proxy to a command buffer in the GPU process.
+  command_buffer_ = channel_->CreateCommandBuffer();
+  if (!command_buffer_) {
+    Destroy();
+    return false;
+  }
+
+  // Initiaize the command buffer.
+  if (!command_buffer_->Initialize(kCommandBufferSize)) {
+    Destroy();
+    return false;
+  }
+
+  // Create the GLES2 helper, which writes the command buffer protocol.
+  gles2_helper_ = new gpu::gles2::GLES2CmdHelper(command_buffer_);
+  if (!gles2_helper_->Initialize()) {
+    Destroy();
+    return false;
+  }
+
+  // Create a transfer buffer used to copy resources between the renderer
+  // process and the GPU process.
+  transfer_buffer_id_ =
+      command_buffer_->CreateTransferBuffer(kTransferBufferSize);
+  if (transfer_buffer_id_ < 0) {
+    Destroy();
+    return false;
+  }
+
+  // Map the buffer into the renderer process's address space.
+  gpu::Buffer transfer_buffer =
+      command_buffer_->GetTransferBuffer(transfer_buffer_id_);
+  if (!transfer_buffer.ptr) {
+    Destroy();
+    return false;
+  }
+
+  // Create the object exposing the OpenGL API.
+  gles2_implementation_ = new gpu::gles2::GLES2Implementation(
+      gles2_helper_,
+      transfer_buffer.size,
+      transfer_buffer.ptr,
+      transfer_buffer_id_);
+
+  return true;
+}
+
+void Context::Destroy() {
+  delete gles2_implementation_;
+  gles2_implementation_ = NULL;
+
+  if (command_buffer_ && transfer_buffer_id_ != 0) {
+    command_buffer_->DestroyTransferBuffer(transfer_buffer_id_);
+    transfer_buffer_id_ = 0;
+  }
+
+  delete gles2_helper_;
+  gles2_helper_ = NULL;
+
+  if (channel_ && command_buffer_) {
+    channel_->DestroyCommandBuffer(command_buffer_);
+    command_buffer_ = NULL;
+  }
+
+  channel_ = NULL;
+}
+
+bool Context::MakeCurrent(Context* context) {
+  g_current_context.Set(context);
+  if (context) {
+    gles2::SetGLContext(context->gles2_implementation_);
+
+    // Don't request latest error status from service. Just use the locally
+    // cached information from the last flush.
+    // TODO(apatrick): I'm not sure if this should actually change the
+    // current context if it fails. For now it gets changed even if it fails
+    // because making GL calls with a NULL context crashes.
+    if (context->command_buffer_->GetLastState().error != gpu::error::kNoError)
+      return false;
+  } else {
+    gles2::SetGLContext(NULL);
+  }
+
+  return true;
+}
+
+bool Context::SwapBuffers() {
+  // Don't request latest error status from service. Just use the locally cached
+  // information from the last flush.
+  if (command_buffer_->GetLastState().error != gpu::error::kNoError)
+    return false;
+
+  gles2_implementation_->SwapBuffers();
+  return true;
+}
+
+Error Context::GetError() {
+  gpu::CommandBuffer::State state = command_buffer_->GetState();
+  if (state.error == gpu::error::kNoError) {
+    return SUCCESS;
+  } else {
+    // All command buffer errors are unrecoverable. The error is treated as a
+    // lost context: destroy the context and create another one.
+    return CONTEXT_LOST;
+  }
+}
+
+#endif  // ENABLE_GPU
+
+Context* CreateContext(GpuChannelHost* channel) {
+#if defined(ENABLE_GPU)
+  scoped_ptr<Context> context(new Context);
+  if (!context->Initialize(channel))
+    return NULL;
+
+  return context.release();
+#else
+  return NULL;
+#endif
+}
+
+bool MakeCurrent(Context* context) {
+#if defined(ENABLE_GPU)
+  return Context::MakeCurrent(context);
+#else
+  return false;
+#endif
+}
+
+Context* GetCurrentContext() {
+#if defined(ENABLE_GPU)
+  return g_current_context.Get();
+#else
+  return NULL;
+#endif
+}
+
+bool SwapBuffers() {
+#if defined(ENABLE_GPU)
+  Context* context = GetCurrentContext();
+  if (!context)
+    return false;
+
+  return context->SwapBuffers();
+#else
+  return false;
+#endif
+}
+
+bool DestroyContext(Context* context) {
+#if defined(ENABLE_GPU)
+  if (!context)
+    return false;
+
+  if (context == GetCurrentContext())
+    MakeCurrent(NULL);
+
+  delete context;
+  return true;
+#else
+  return false;
+#endif
+}
+
+Error GetError() {
+#if defined(ENABLE_GPU)
+  Context* context = GetCurrentContext();
+  if (!context)
+    return BAD_CONTEXT;
+
+  return context->GetError();
+#else
+  return NOT_INITIALIZED;
+#endif
+}
+
+}  // namespace ggl