/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LIBRENDER_WINDOW_SURFACE_H
#define _LIBRENDER_WINDOW_SURFACE_H

#include "anbox/graphics/emugl/ColorBuffer.h"
#include "anbox/graphics/emugl/RenderContext.h"

#include <EGL/egl.h>
#include <GLES/gl.h>

// A class used to model a guest-side window surface. The implementation
// uses a host Pbuffer to act as the EGL rendering surface instead.
class WindowSurface {
 public:
  // Create a new WindowSurface instance.
  // |display| is the host EGLDisplay value.
  // |config| is the host EGLConfig value.
  // |width| and |height| are the initial size of the Pbuffer.
  // Return a new WindowSurface instance on success, or NULL on failure.
  static WindowSurface* create(EGLDisplay display, EGLConfig config, int width,
                               int height);

  // Destructor.
  ~WindowSurface();

  // Retrieve the host EGLSurface of the WindowSurface's Pbuffer.
  EGLSurface getEGLSurface() const { return mSurface; }

  // Attach a ColorBuffer to this WindowSurface.
  // Once attached, calling flushColorBuffer() will copy the Pbuffer's
  // pixels to the color buffer.
  //
  // IMPORTANT: This automatically resizes the Pbuffer's to the ColorBuffer's
  // dimensions. Potentially losing pixel values in the process.
  void setColorBuffer(ColorBufferPtr p_colorBuffer);

  // Copy the Pbuffer's pixels to the attached color buffer.
  // Returns true on success, or false on error (e.g. if there is no
  // attached color buffer).
  bool flushColorBuffer();

  // Used by bind() below.
  enum BindType { BIND_READ,
                  BIND_DRAW,
                  BIND_READDRAW };

  // TODO(digit): What is this used for exactly? For example, the
  // mReadContext is never used by this class. The mDrawContext is only
  // used temporarily during flushColorBuffer() operation, and could be
  // passed as a parameter to the function instead. Maybe this is only used
  // to increment reference counts on the smart pointers.
  //
  // Bind a context to the WindowSurface (huh? Normally you would bind a
  // surface to the context, not the other way around)
  //
  // |p_ctx| is a RenderContext pointer.
  // |p_bindType| is the type of bind. For BIND_READ, this assigns |p_ctx|
  // to mReadContext, for BIND_DRAW, it assigns it to mDrawContext, and for
  // for BIND_READDRAW, it assigns it to both.
  void bind(RenderContextPtr p_ctx, BindType p_bindType);

 private:
  WindowSurface();
  WindowSurface(const WindowSurface& other);

  explicit WindowSurface(EGLDisplay display, EGLConfig config);

  bool resize(unsigned int p_width, unsigned int p_height);

 private:
  EGLSurface mSurface;
  ColorBufferPtr mAttachedColorBuffer;
  RenderContextPtr mReadContext;
  RenderContextPtr mDrawContext;
  GLuint mWidth;
  GLuint mHeight;
  EGLConfig mConfig;
  EGLDisplay mDisplay;
};

typedef std::shared_ptr<WindowSurface> WindowSurfacePtr;

#endif  // _LIBRENDER_WINDOW_SURFACE_H