// Copyright (c) 2012 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 "ui/gl/scoped_binders.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_state_restorer.h"

namespace gl {

ScopedFramebufferBinder::ScopedFramebufferBinder(unsigned int fbo)
    : state_restorer_(!GLContext::GetCurrent()
                          ? NULL
                          : GLContext::GetCurrent()->GetGLStateRestorer()),
      old_fbo_(-1) {
  if (!state_restorer_)
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &old_fbo_);
  glBindFramebufferEXT(GL_FRAMEBUFFER, fbo);
}

ScopedFramebufferBinder::~ScopedFramebufferBinder() {
  if (state_restorer_) {
    DCHECK(!!GLContext::GetCurrent());
    DCHECK_EQ(state_restorer_, GLContext::GetCurrent()->GetGLStateRestorer());
    state_restorer_->RestoreFramebufferBindings();
  } else {
    glBindFramebufferEXT(GL_FRAMEBUFFER, old_fbo_);
  }
}

ScopedActiveTexture::ScopedActiveTexture(unsigned int texture)
    : old_texture_(-1) {
  glGetIntegerv(GL_ACTIVE_TEXTURE, &old_texture_);
  glActiveTexture(texture);
}

ScopedActiveTexture::~ScopedActiveTexture() {
  glActiveTexture(old_texture_);
}

ScopedTextureBinder::ScopedTextureBinder(unsigned int target, unsigned int id)
    : state_restorer_(!GLContext::GetCurrent()
                          ? NULL
                          : GLContext::GetCurrent()->GetGLStateRestorer()),
      target_(target),
      old_id_(-1) {
  if (!state_restorer_) {
    GLenum target_getter = 0;
    switch (target) {
      case GL_TEXTURE_2D:
        target_getter = GL_TEXTURE_BINDING_2D;
        break;
      case GL_TEXTURE_CUBE_MAP:
        target_getter = GL_TEXTURE_BINDING_CUBE_MAP;
        break;
      case GL_TEXTURE_EXTERNAL_OES:
        target_getter = GL_TEXTURE_BINDING_EXTERNAL_OES;
        break;
      case GL_TEXTURE_RECTANGLE_ARB:
        target_getter = GL_TEXTURE_BINDING_RECTANGLE_ARB;
        break;
      default:
        NOTIMPLEMENTED() << " Target not supported.";
    }
    glGetIntegerv(target_getter, &old_id_);
  }
  glBindTexture(target_, id);
}

ScopedTextureBinder::~ScopedTextureBinder() {
  if (state_restorer_) {
    DCHECK(!!GLContext::GetCurrent());
    DCHECK_EQ(state_restorer_, GLContext::GetCurrent()->GetGLStateRestorer());
    state_restorer_->RestoreActiveTextureUnitBinding(target_);
  } else {
    glBindTexture(target_, old_id_);
  }
}

ScopedUseProgram::ScopedUseProgram(unsigned int program) : old_program_(-1) {
  glGetIntegerv(GL_CURRENT_PROGRAM, &old_program_);
  glUseProgram(program);
}

ScopedUseProgram::~ScopedUseProgram() {
  glUseProgram(old_program_);
}

ScopedVertexAttribArray::ScopedVertexAttribArray(unsigned int index,
                                                 int size,
                                                 unsigned int type,
                                                 char normalized,
                                                 int stride,
                                                 const void* pointer)
    : buffer_(0),
      enabled_(GL_FALSE),
      index_(index),
      size_(-1),
      type_(-1),
      normalized_(GL_FALSE),
      stride_(0),
      pointer_(0) {
  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING, &buffer_);
  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_ENABLED, &enabled_);
  glEnableVertexAttribArray(index);

  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_SIZE, &size_);
  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_TYPE, &type_);
  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, &normalized_);
  glGetVertexAttribiv(index, GL_VERTEX_ATTRIB_ARRAY_STRIDE, &stride_);
  glGetVertexAttribPointerv(index, GL_VERTEX_ATTRIB_ARRAY_POINTER, &pointer_);

  glVertexAttribPointer(index, size, type, normalized, stride, pointer);
}

ScopedVertexAttribArray::~ScopedVertexAttribArray() {
  ScopedBufferBinder buffer_binder(GL_ARRAY_BUFFER, buffer_);
  glVertexAttribPointer(index_, size_, type_, normalized_, stride_, pointer_);
  if (enabled_ == GL_FALSE) {
    glDisableVertexAttribArray(index_);
  }
}

ScopedBufferBinder::ScopedBufferBinder(unsigned int target, unsigned int id)
    : target_(target), old_id_(-1) {
  GLenum target_getter = 0;
  switch (target) {
    case GL_ARRAY_BUFFER:
      target_getter = GL_ARRAY_BUFFER_BINDING;
      break;
    default:
      NOTIMPLEMENTED() << " Target not supported.";
  }
  glGetIntegerv(target_getter, &old_id_);
  glBindBuffer(target_, id);
}

ScopedBufferBinder::~ScopedBufferBinder() {
  glBindBuffer(target_, old_id_);
}

ScopedViewport::ScopedViewport(int x, int y, int width, int height) {
  glGetIntegerv(GL_VIEWPORT, data_);
  glViewport(x, y, width, height);
}

ScopedViewport::~ScopedViewport() {
  glViewport(data_[0], data_[1], data_[2], data_[3]);
}

ScopedColorMask::ScopedColorMask(char red, char green, char blue, char alpha) {
  glGetBooleanv(GL_COLOR_WRITEMASK, colors_);
  glColorMask(red, green, blue, alpha);
}

ScopedColorMask::~ScopedColorMask() {
  glColorMask(colors_[0], colors_[1], colors_[2], colors_[3]);
}

ScopedCapability::ScopedCapability(unsigned capability, unsigned char enabled)
    : capability_(capability) {
  enabled_ = glIsEnabled(capability_);
  if (enabled == GL_TRUE) {
    glEnable(capability);
  } else {
    glDisable(capability);
  }
}

ScopedCapability::~ScopedCapability() {
  if (enabled_ == GL_TRUE) {
    glEnable(capability_);
  } else {
    glDisable(capability_);
  }
}

}  // namespace gl