Implement TransformFeedbackManager in GPU command buffer.

gpu/command_buffer/service/transform_feedback_manager.h

+// Copyright (c) 2016 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.
+
+#ifndef GPU_COMMAND_BUFFER_SERVICE_TRANSFORM_FEEDBACK_MANAGER_H_
+#define GPU_COMMAND_BUFFER_SERVICE_TRANSFORM_FEEDBACK_MANAGER_H_
+
+#include <vector>
+
+#include "base/containers/hash_tables.h"
+#include "base/memory/ref_counted.h"
+#include "gpu/command_buffer/service/gl_utils.h"
+#include "gpu/command_buffer/service/indexed_buffer_binding_host.h"
+#include "gpu/gpu_export.h"
+
+namespace gfx {
+struct GLVersionInfo;
+};
+
+namespace gpu {
+namespace gles2 {
+
+class Buffer;
+class TransformFeedbackManager;
+
+// Info about TransformFeedbacks currently in the system.
+class GPU_EXPORT TransformFeedback : public IndexedBufferBindingHost {
+ public:
+  TransformFeedback(TransformFeedbackManager* manager, GLuint service_id);
+
+  // All the following functions do state update and call the underlying GL
+  // function.  All validations have been done already and the GL function is
+  // guaranteed to succeed.
+  void DoBindTransformFeedback(GLenum target);
+  void DoBeginTransformFeedback(GLenum primitive_mode);
+  void DoEndTransformFeedback();
+  void DoPauseTransformFeedback();
+  void DoResumeTransformFeedback();
+
+  GLuint service_id() const {
+    return service_id_;
+  }
+
+  bool has_been_bound() const {
+    return has_been_bound_;
+  }
+
+  bool active() const {
+    return active_;
+  }
+
+  bool paused() const {
+    return paused_;
+  }
+
+  GLenum primitive_mode() const {
+    return primitive_mode_;
+  }
+
+ private:
+  ~TransformFeedback() override;
+
+  // The manager that owns this Buffer.
+  TransformFeedbackManager* manager_;
+
+  GLuint service_id_;
+
+  bool has_been_bound_;
+
+  bool active_;
+  bool paused_;
+
+  GLenum primitive_mode_;
+};
+
+// This class keeps tracks of the transform feedbacks and their states.
+class GPU_EXPORT TransformFeedbackManager {
+ public:
+  // |needs_emulation| is true on Desktop GL 4.1 or lower.
+  TransformFeedbackManager(GLuint max_transform_feedback_separate_attribs,
+                           bool needs_emulation);
+  ~TransformFeedbackManager();
+
+  void MarkContextLost() {
+    lost_context_ = true;
+  }
+
+  // Must call before destruction.
+  void Destroy();
+
+  // Creates a TransformFeedback from the given client/service IDs and
+  // insert it into the list.
+  TransformFeedback* CreateTransformFeedback(
+      GLuint client_id, GLuint service_id);
+
+  TransformFeedback* GetTransformFeedback(GLuint client_id);
+
+  // Removes a TransformFeedback info for the given client ID.
+  void RemoveTransformFeedback(GLuint client_id);
+
+  void RemoveBoundBuffer(Buffer* buffer);
+
+  GLuint max_transform_feedback_separate_attribs() const {
+    return max_transform_feedback_separate_attribs_;
+  }
+
+  bool needs_emulation() const {
+    return needs_emulation_;
+  }
+
+  bool lost_context() const {
+    return lost_context_;
+  }
+
+ private:
+  // Info for each transform feedback in the system.
+  base::hash_map<GLuint,
+                 scoped_refptr<TransformFeedback> > transform_feedbacks_;
+
+  GLuint max_transform_feedback_separate_attribs_;
+
+  bool needs_emulation_;
+  bool lost_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(TransformFeedbackManager);
+};
+
+}  // namespace gles2
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_SERVICE_TRANSFORM_FEEDBACK_MANAGER_H_