gpu/command_buffer/service/framebuffer_manager.cc

// 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 "gpu/command_buffer/service/framebuffer_manager.h"

#include <stddef.h>
#include <stdint.h>

#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/stringprintf.h"
#include "gpu/command_buffer/common/gles2_cmd_utils.h"
#include "gpu/command_buffer/service/framebuffer_completeness_cache.h"
#include "gpu/command_buffer/service/renderbuffer_manager.h"
#include "gpu/command_buffer/service/texture_manager.h"
#include "ui/gl/gl_bindings.h"

namespace gpu {
namespace gles2 {

namespace {

bool DetectWebGL1DepthStencilAttachmentConflicts(
    uint32_t needed_channels, uint32_t channels) {
  switch (needed_channels) {
    case GLES2Util::kDepth:
    case GLES2Util::kStencil:
    case GLES2Util::kDepth | GLES2Util::kStencil:
      return (needed_channels != channels);
    default:
      return false;
  }
}

}  // namespace anonymous

DecoderFramebufferState::DecoderFramebufferState()
    : clear_state_dirty(false),
      bound_read_framebuffer(NULL),
      bound_draw_framebuffer(NULL) {
}

DecoderFramebufferState::~DecoderFramebufferState() {
}

class RenderbufferAttachment
    : public Framebuffer::Attachment {
 public:
  explicit RenderbufferAttachment(
      Renderbuffer* renderbuffer)
      : renderbuffer_(renderbuffer) {
  }

  GLsizei width() const override { return renderbuffer_->width(); }

  GLsizei height() const override { return renderbuffer_->height(); }

  GLenum internal_format() const override {
    return renderbuffer_->internal_format();
  }

  GLenum texture_type() const override {
    return TextureManager::ExtractTypeFromStorageFormat(
        renderbuffer_->internal_format());
  }

  GLsizei samples() const override { return renderbuffer_->samples(); }

  GLuint object_name() const override { return renderbuffer_->client_id(); }

  bool cleared() const override { return renderbuffer_->cleared(); }

  void SetCleared(RenderbufferManager* renderbuffer_manager,
                  TextureManager* /* texture_manager */,
                  bool cleared) override {
    DCHECK(renderbuffer_manager);
    renderbuffer_manager->SetCleared(renderbuffer_.get(), cleared);
  }

  bool IsPartiallyCleared() const override { return false; }

  bool IsTextureAttachment() const override { return false; }
  bool IsRenderbufferAttachment() const override { return true; }

  bool IsTexture(TextureRef* /* texture */) const override { return false; }

  bool IsRenderbuffer(Renderbuffer* renderbuffer) const override {
    return renderbuffer_.get() == renderbuffer;
  }

  bool Is3D() const override { return false; }

  bool CanRenderTo(const FeatureInfo*) const override { return true; }

  void DetachFromFramebuffer(Framebuffer* framebuffer) const override {
    // Nothing to do for renderbuffers.
  }

  bool IsLayerValid() const override { return true; }

  bool ValidForAttachmentType(GLenum attachment_type,
                              ContextType context_type,
                              uint32_t max_color_attachments) override {
    uint32_t need = GLES2Util::GetChannelsNeededForAttachmentType(
        attachment_type, max_color_attachments);
    DCHECK_NE(0u, need);
    uint32_t have = GLES2Util::GetChannelsForFormat(internal_format());
    if (context_type == CONTEXT_TYPE_WEBGL1 &&
        DetectWebGL1DepthStencilAttachmentConflicts(need, have))
      return false;
    return (need & have) != 0;
  }

  Renderbuffer* renderbuffer() const {
    return renderbuffer_.get();
  }

  size_t GetSignatureSize(TextureManager* texture_manager) const override {
    return renderbuffer_->GetSignatureSize();
  }

  void AddToSignature(TextureManager* texture_manager,
                      std::string* signature) const override {
    DCHECK(signature);
    renderbuffer_->AddToSignature(signature);
  }

  bool FormsFeedbackLoop(TextureRef* /* texture */,
                         GLint /*level */) const override {
    return false;
  }

  bool EmulatingRGB() const override { return false; }

 protected:
  ~RenderbufferAttachment() override {}

 private:
  scoped_refptr<Renderbuffer> renderbuffer_;

  DISALLOW_COPY_AND_ASSIGN(RenderbufferAttachment);
};

class TextureAttachment
    : public Framebuffer::Attachment {
 public:
  TextureAttachment(
      TextureRef* texture_ref, GLenum target, GLint level,
      GLsizei samples, GLint layer)
      : texture_ref_(texture_ref),
        target_(target),
        level_(level),
        samples_(samples),
        layer_(layer) {
  }

  GLsizei width() const override {
    GLsizei temp_width = 0;
    GLsizei temp_height = 0;
    texture_ref_->texture()->GetLevelSize(
        target_, level_, &temp_width, &temp_height, nullptr);
    return temp_width;
  }

  GLsizei height() const override {
    GLsizei temp_width = 0;
    GLsizei temp_height = 0;
    texture_ref_->texture()->GetLevelSize(
        target_, level_, &temp_width, &temp_height, nullptr);
    return temp_height;
  }

  GLenum internal_format() const override {
    GLenum temp_type = 0;
    GLenum temp_internal_format = 0;
    texture_ref_->texture()->GetLevelType(
        target_, level_, &temp_type, &temp_internal_format);
    return temp_internal_format;
  }

  GLenum texture_type() const override {
    GLenum temp_type = 0;
    GLenum temp_internal_format = 0;
    texture_ref_->texture()->GetLevelType(
        target_, level_, &temp_type, &temp_internal_format);
    return temp_type;
  }

  GLsizei samples() const override { return samples_; }

  GLint layer() const { return layer_; }

  GLenum target() const { return target_; }

  GLint level() const { return level_; }

  GLuint object_name() const override { return texture_ref_->client_id(); }

  bool cleared() const override {
    return texture_ref_->texture()->IsLevelCleared(target_, level_);
  }

  void SetCleared(RenderbufferManager* /* renderbuffer_manager */,
                  TextureManager* texture_manager,
                  bool cleared) override {
    DCHECK(texture_manager);
    texture_manager->SetLevelCleared(
        texture_ref_.get(), target_, level_, cleared);
  }

  bool IsPartiallyCleared() const override {
    return texture_ref_->texture()->IsLevelPartiallyCleared(target_, level_);
  }

  bool IsTextureAttachment() const override { return true; }
  bool IsRenderbufferAttachment() const override { return false; }

  bool IsTexture(TextureRef* texture) const override {
    return texture == texture_ref_.get();
  }

  bool IsRenderbuffer(Renderbuffer* /* renderbuffer */) const override {
    return false;
  }

  bool Is3D() const override {
    return (target_ == GL_TEXTURE_3D || target_ == GL_TEXTURE_2D_ARRAY);
  }

  TextureRef* texture() const {
    return texture_ref_.get();
  }

  bool CanRenderTo(const FeatureInfo* feature_info) const override {
    return texture_ref_->texture()->CanRenderTo(feature_info, level_);
  }

  void DetachFromFramebuffer(Framebuffer* framebuffer) const override {
    texture_ref_->texture()->DetachFromFramebuffer();
  }

  bool IsLayerValid() const override {
    Texture* texture = texture_ref_->texture();
    DCHECK(texture);
    GLsizei width, height, depth;
    return (texture->GetLevelSize(target_, level_, &width, &height, &depth) &&
            layer_ < depth);
  }

  bool ValidForAttachmentType(GLenum attachment_type,
                              ContextType context_type,
                              uint32_t max_color_attachments) override {
    GLenum type = 0;
    GLenum internal_format = 0;
    if (!texture_ref_->texture()->GetLevelType(
        target_, level_, &type, &internal_format)) {
      return false;
    }
    uint32_t need = GLES2Util::GetChannelsNeededForAttachmentType(
        attachment_type, max_color_attachments);
    DCHECK_NE(0u, need);
    uint32_t have = GLES2Util::GetChannelsForFormat(internal_format);

    // Workaround for NVIDIA drivers that incorrectly expose these formats as
    // renderable:
    if (internal_format == GL_LUMINANCE || internal_format == GL_ALPHA ||
        internal_format == GL_LUMINANCE_ALPHA) {
      return false;
    }
    if (context_type == CONTEXT_TYPE_WEBGL1 &&
        DetectWebGL1DepthStencilAttachmentConflicts(need, have))
      return need == have;
    return (need & have) != 0;
  }

  size_t GetSignatureSize(TextureManager* texture_manager) const override {
    return texture_manager->GetSignatureSize();
  }

  void AddToSignature(TextureManager* texture_manager,
                      std::string* signature) const override {
    DCHECK(signature);
    texture_manager->AddToSignature(
        texture_ref_.get(), target_, level_, signature);
  }

  bool FormsFeedbackLoop(TextureRef* texture, GLint level) const override {
    return texture == texture_ref_.get() && level == level_;
  }

  bool EmulatingRGB() const override {
    return texture_ref_->texture()->EmulatingRGB();
  }

 protected:
  ~TextureAttachment() override {}

 private:
  scoped_refptr<TextureRef> texture_ref_;
  GLenum target_;
  GLint level_;
  GLsizei samples_;
  GLint layer_;

  DISALLOW_COPY_AND_ASSIGN(TextureAttachment);
};

FramebufferManager::FramebufferManager(
    uint32_t max_draw_buffers,
    uint32_t max_color_attachments,
    ContextType context_type,
    const scoped_refptr<FramebufferCompletenessCache>&
        framebuffer_combo_complete_cache)
    : framebuffer_state_change_count_(1),
      framebuffer_count_(0),
      have_context_(true),
      max_draw_buffers_(max_draw_buffers),
      max_color_attachments_(max_color_attachments),
      context_type_(context_type),
      framebuffer_combo_complete_cache_(framebuffer_combo_complete_cache) {
  DCHECK_GT(max_draw_buffers_, 0u);
  DCHECK_GT(max_color_attachments_, 0u);
}

FramebufferManager::~FramebufferManager() {
  DCHECK(framebuffers_.empty());
  // If this triggers, that means something is keeping a reference to a
  // Framebuffer belonging to this.
  CHECK_EQ(framebuffer_count_, 0u);
}

void Framebuffer::MarkAsDeleted() {
  deleted_ = true;
  while (!attachments_.empty()) {
    Attachment* attachment = attachments_.begin()->second.get();
    attachment->DetachFromFramebuffer(this);
    attachments_.erase(attachments_.begin());
  }
}

void FramebufferManager::Destroy(bool have_context) {
  have_context_ = have_context;
  framebuffers_.clear();
}

void FramebufferManager::StartTracking(
    Framebuffer* /* framebuffer */) {
  ++framebuffer_count_;
}

void FramebufferManager::StopTracking(
    Framebuffer* /* framebuffer */) {
  --framebuffer_count_;
}

void FramebufferManager::CreateFramebuffer(
    GLuint client_id, GLuint service_id) {
  std::pair<FramebufferMap::iterator, bool> result =
      framebuffers_.insert(
          std::make_pair(
              client_id,
              scoped_refptr<Framebuffer>(
                  new Framebuffer(this, service_id))));
  DCHECK(result.second);
}

Framebuffer::Framebuffer(
    FramebufferManager* manager, GLuint service_id)
    : manager_(manager),
      deleted_(false),
      service_id_(service_id),
      has_been_bound_(false),
      framebuffer_complete_state_count_id_(0),
      read_buffer_(GL_COLOR_ATTACHMENT0) {
  manager->StartTracking(this);
  DCHECK_GT(manager->max_draw_buffers_, 0u);
  draw_buffers_.reset(new GLenum[manager->max_draw_buffers_]);
  draw_buffers_[0] = GL_COLOR_ATTACHMENT0;
  for (uint32_t i = 1; i < manager->max_draw_buffers_; ++i)
    draw_buffers_[i] = GL_NONE;
}

Framebuffer::~Framebuffer() {
  if (manager_) {
    if (manager_->have_context_) {
      GLuint id = service_id();
      glDeleteFramebuffersEXT(1, &id);
    }
    manager_->StopTracking(this);
    manager_ = NULL;
  }
}

bool Framebuffer::HasUnclearedAttachment(
    GLenum attachment) const {
  AttachmentMap::const_iterator it =
      attachments_.find(attachment);
  if (it != attachments_.end()) {
    const Attachment* attachment = it->second.get();
    return !attachment->cleared();
  }
  return false;
}

bool Framebuffer::HasUnclearedColorAttachments() const {
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    if (it->first >= GL_COLOR_ATTACHMENT0 &&
        it->first < GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_) {
      const Attachment* attachment = it->second.get();
      if (!attachment->cleared())
        return true;
    }
  }
  return false;
}

bool Framebuffer::HasUnclearedIntRenderbufferAttachments() const {
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    if (!it->second->IsRenderbufferAttachment() || it->second->cleared())
      continue;
    if (GLES2Util::IsIntegerFormat(it->second->internal_format()))
      return true;
  }
  return false;
}

void Framebuffer::ClearUnclearedIntRenderbufferAttachments(
    RenderbufferManager* renderbuffer_manager) {
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    if (!it->second->IsRenderbufferAttachment() || it->second->cleared())
      continue;
    GLenum internal_format = it->second->internal_format();
    if (GLES2Util::IsIntegerFormat(internal_format)) {
      GLenum attaching_point = it->first;
      DCHECK_LE(static_cast<GLenum>(GL_COLOR_ATTACHMENT0), attaching_point);
      DCHECK_GT(GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_,
                attaching_point);
      GLint drawbuffer = it->first - GL_COLOR_ATTACHMENT0;
      if (GLES2Util::IsUnsignedIntegerFormat(internal_format)) {
        const GLuint kZero[] = { 0u, 0u, 0u, 0u };
        glClearBufferuiv(GL_COLOR, drawbuffer, kZero);
      } else {
        DCHECK(GLES2Util::IsSignedIntegerFormat(internal_format));
        const static GLint kZero[] = { 0, 0, 0, 0 };
        glClearBufferiv(GL_COLOR, drawbuffer, kZero);
      }
      it->second->SetCleared(renderbuffer_manager, nullptr, true);
    }
  }
}

bool Framebuffer::HasSRGBAttachments() const {
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    GLenum internal_format = it->second->internal_format();
    switch (internal_format) {
      case GL_SRGB8:
      case GL_SRGB8_ALPHA8:
      case GL_SRGB_EXT:
      case GL_SRGB_ALPHA_EXT:
        return true;
      default:
        break;
    }
  }
  return false;
}

bool Framebuffer::PrepareDrawBuffersForClear() const {
  std::unique_ptr<GLenum[]> buffers(new GLenum[manager_->max_draw_buffers_]);
  for (uint32_t i = 0; i < manager_->max_draw_buffers_; ++i)
    buffers[i] = GL_NONE;
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    if (it->first >= GL_COLOR_ATTACHMENT0 &&
        it->first < GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_ &&
        !it->second->cleared()) {
      // There should be no partially cleared images, uncleared int/3d images.
      // This is because ClearUnclearedIntOr3DImagesOrPartiallyClearedImages()
      // is called before this.
      DCHECK(!GLES2Util::IsIntegerFormat(it->second->internal_format()));
      DCHECK(!it->second->IsPartiallyCleared());
      DCHECK(!it->second->Is3D());
      buffers[it->first - GL_COLOR_ATTACHMENT0] = it->first;
    }
  }
  bool different = false;
  for (uint32_t i = 0; i < manager_->max_draw_buffers_; ++i) {
    if (buffers[i] != draw_buffers_[i]) {
      different = true;
      break;
    }
  }
  if (different)
    glDrawBuffersARB(manager_->max_draw_buffers_, buffers.get());
  return different;
}

void Framebuffer::RestoreDrawBuffersAfterClear() const {
  glDrawBuffersARB(manager_->max_draw_buffers_, draw_buffers_.get());
}

void Framebuffer::ClearUnclearedIntOr3DTexturesOrPartiallyClearedTextures(
    GLES2Decoder* decoder,
    TextureManager* texture_manager) {
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    if (!it->second->IsTextureAttachment() || it->second->cleared())
      continue;
    TextureAttachment* attachment =
        reinterpret_cast<TextureAttachment*>(it->second.get());
    if (attachment->IsPartiallyCleared() || attachment->Is3D() ||
        GLES2Util::IsIntegerFormat(attachment->internal_format())) {
      texture_manager->ClearTextureLevel(decoder,
                                         attachment->texture(),
                                         attachment->target(),
                                         attachment->level());
    }
  }
}

void Framebuffer::MarkAttachmentAsCleared(
      RenderbufferManager* renderbuffer_manager,
      TextureManager* texture_manager,
      GLenum attachment,
      bool cleared) {
  AttachmentMap::iterator it = attachments_.find(attachment);
  if (it != attachments_.end()) {
    Attachment* a = it->second.get();
    if (a->cleared() != cleared) {
      a->SetCleared(renderbuffer_manager,
                    texture_manager,
                    cleared);
    }
  }
}

void Framebuffer::MarkAttachmentsAsCleared(
      RenderbufferManager* renderbuffer_manager,
      TextureManager* texture_manager,
      bool cleared) {
  for (AttachmentMap::iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    Attachment* attachment = it->second.get();
    if (attachment->cleared() != cleared) {
      attachment->SetCleared(renderbuffer_manager, texture_manager, cleared);
    }
  }
}

bool Framebuffer::HasColorAttachment(int index) const {
  return attachments_.find(GL_COLOR_ATTACHMENT0 + index) != attachments_.end();
}

bool Framebuffer::HasDepthAttachment() const {
  return attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT) != attachments_.end() ||
         attachments_.find(GL_DEPTH_ATTACHMENT) != attachments_.end();
}

bool Framebuffer::HasStencilAttachment() const {
  return attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT) != attachments_.end() ||
         attachments_.find(GL_STENCIL_ATTACHMENT) != attachments_.end();
}

GLenum Framebuffer::GetReadBufferInternalFormat() const {
  if (read_buffer_ == GL_NONE)
    return 0;
  AttachmentMap::const_iterator it = attachments_.find(read_buffer_);
  if (it == attachments_.end()) {
    return 0;
  }
  const Attachment* attachment = it->second.get();
  if (attachment->EmulatingRGB()) {
    DCHECK_EQ(static_cast<GLenum>(GL_RGBA), attachment->internal_format());
    return GL_RGB;
  }
  return attachment->internal_format();
}

GLenum Framebuffer::GetReadBufferTextureType() const {
  if (read_buffer_ == GL_NONE)
    return 0;
  AttachmentMap::const_iterator it = attachments_.find(read_buffer_);
  if (it == attachments_.end()) {
    return 0;
  }
  const Attachment* attachment = it->second.get();
  return attachment->texture_type();
}

GLsizei Framebuffer::GetSamples() const {
  // Assume the framebuffer is complete, so return any attachment's samples.
  auto iter = attachments_.begin();
  if (iter == attachments_.end())
    return -1;
  Attachment* attachment = iter->second.get();
  DCHECK(attachment);
  return attachment->samples();
}

GLenum Framebuffer::GetDepthFormat() const {
  auto iter = attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT);
  if (iter == attachments_.end())
    iter = attachments_.find(GL_DEPTH_ATTACHMENT);
  if (iter == attachments_.end())
    return 0;
  Attachment* attachment = iter->second.get();
  DCHECK(attachment);
  return attachment->internal_format();
}

GLenum Framebuffer::GetStencilFormat() const {
  auto iter = attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT);
  if (iter == attachments_.end())
    iter = attachments_.find(GL_STENCIL_ATTACHMENT);
  if (iter == attachments_.end())
    return 0;
  Attachment* attachment = iter->second.get();
  DCHECK(attachment);
  return attachment->internal_format();
}

GLenum Framebuffer::IsPossiblyComplete(const FeatureInfo* feature_info) const {
  if (attachments_.empty()) {
    return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
  }

  GLsizei width = -1;
  GLsizei height = -1;
  GLsizei samples = -1;
  const bool kSamplesMustMatch =
      feature_info->context_type() == CONTEXT_TYPE_WEBGL1 ||
      feature_info->context_type() == CONTEXT_TYPE_WEBGL2 ||
      !feature_info->feature_flags().chromium_framebuffer_mixed_samples;

  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    GLenum attachment_type = it->first;
    Attachment* attachment = it->second.get();
    if (!attachment->ValidForAttachmentType(attachment_type,
                                            feature_info->context_type(),
                                            manager_->max_color_attachments_)) {
      return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
    }
    if (!attachment->IsLayerValid()) {
      return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
    }
    if (width < 0) {
      width = attachment->width();
      height = attachment->height();
      if (width == 0 || height == 0) {
        return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
      }
    } else if (attachment->width() != width || attachment->height() != height) {
      // Since DirectX doesn't allow attachments to be of different sizes,
      // even though ES3 allows it, it is still forbidden to ensure consistent
      // behaviors across platforms.
      return GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT;
    }

    if (kSamplesMustMatch) {
      if (samples < 0) {
        samples = attachment->samples();
      } else if (attachment->samples() != samples) {
        // It's possible that the specified samples isn't the actual samples a
        // GL implementation uses, but we always return INCOMPLETE_MULTISAMPLE
        // here to ensure consistent behaviors across platforms.
        return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE;
      }
    }
    if (!attachment->CanRenderTo(feature_info)) {
      return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
    }
  }

  // This does not mean the framebuffer is actually complete. It just means our
  // checks passed.
  return GL_FRAMEBUFFER_COMPLETE;
}

GLenum Framebuffer::GetStatus(
    TextureManager* texture_manager, GLenum target) const {
  if (!manager_->GetFramebufferComboCompleteCache()) {
    return glCheckFramebufferStatusEXT(target);
  }
  // Check if we have this combo already.
  std::string signature;

  size_t signature_size = sizeof(target);
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    Attachment* attachment = it->second.get();
    signature_size +=
        sizeof(it->first) + attachment->GetSignatureSize(texture_manager);
  }

  signature.reserve(signature_size);
  signature.append(reinterpret_cast<const char*>(&target), sizeof(target));

  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    Attachment* attachment = it->second.get();
    signature.append(reinterpret_cast<const char*>(&it->first),
                     sizeof(it->first));
    attachment->AddToSignature(texture_manager, &signature);
  }
  DCHECK(signature.size() == signature_size);

  if (manager_->GetFramebufferComboCompleteCache()->IsComplete(signature)) {
    return GL_FRAMEBUFFER_COMPLETE;
  }

  GLenum result = glCheckFramebufferStatusEXT(target);

  if (result == GL_FRAMEBUFFER_COMPLETE) {
    manager_->GetFramebufferComboCompleteCache()->SetComplete(signature);
  }

  return result;
}

bool Framebuffer::IsCleared() const {
  // are all the attachments cleaared?
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    Attachment* attachment = it->second.get();
    if (!attachment->cleared()) {
      return false;
    }
  }
  return true;
}

GLenum Framebuffer::GetDrawBuffer(GLenum draw_buffer) const {
  GLsizei index = static_cast<GLsizei>(
      draw_buffer - GL_DRAW_BUFFER0_ARB);
  CHECK(index >= 0 &&
        index < static_cast<GLsizei>(manager_->max_draw_buffers_));
  return draw_buffers_[index];
}

void Framebuffer::SetDrawBuffers(GLsizei n, const GLenum* bufs) {
  DCHECK(n <= static_cast<GLsizei>(manager_->max_draw_buffers_));
  for (GLsizei i = 0; i < n; ++i)
    draw_buffers_[i] = bufs[i];
}

bool Framebuffer::HasAlphaMRT() const {
  for (uint32_t i = 0; i < manager_->max_draw_buffers_; ++i) {
    if (draw_buffers_[i] != GL_NONE) {
      const Attachment* attachment = GetAttachment(draw_buffers_[i]);
      if (!attachment)
        continue;
      if ((GLES2Util::GetChannelsForFormat(
               attachment->internal_format()) & 0x0008) != 0)
        return true;
    }
  }
  return false;
}

bool Framebuffer::HasSameInternalFormatsMRT() const {
  GLenum internal_format = 0;
  for (uint32_t i = 0; i < manager_->max_draw_buffers_; ++i) {
    if (draw_buffers_[i] != GL_NONE) {
      const Attachment* attachment = GetAttachment(draw_buffers_[i]);
      if (!attachment)
        continue;
      if (!internal_format) {
        internal_format = attachment->internal_format();
      } else if (internal_format != attachment->internal_format()) {
        return false;
      }
    }
  }
  return true;
}

void Framebuffer::UnbindRenderbuffer(
    GLenum target, Renderbuffer* renderbuffer) {
  bool done;
  do {
    done = true;
    for (AttachmentMap::const_iterator it = attachments_.begin();
         it != attachments_.end(); ++it) {
      Attachment* attachment = it->second.get();
      if (attachment->IsRenderbuffer(renderbuffer)) {
        // TODO(gman): manually detach renderbuffer.
        // glFramebufferRenderbufferEXT(target, it->first, GL_RENDERBUFFER, 0);
        AttachRenderbuffer(it->first, NULL);
        done = false;
        break;
      }
    }
  } while (!done);
}

void Framebuffer::UnbindTexture(
    GLenum target, TextureRef* texture_ref) {
  bool done;
  do {
    done = true;
    for (AttachmentMap::const_iterator it = attachments_.begin();
         it != attachments_.end(); ++it) {
      Attachment* attachment = it->second.get();
      if (attachment->IsTexture(texture_ref)) {
        // TODO(gman): manually detach texture.
        // glFramebufferTexture2DEXT(target, it->first, GL_TEXTURE_2D, 0, 0);
        AttachTexture(it->first, NULL, GL_TEXTURE_2D, 0, 0);
        done = false;
        break;
      }
    }
  } while (!done);
}

Framebuffer* FramebufferManager::GetFramebuffer(
    GLuint client_id) {
  FramebufferMap::iterator it = framebuffers_.find(client_id);
  return it != framebuffers_.end() ? it->second.get() : NULL;
}

void FramebufferManager::RemoveFramebuffer(GLuint client_id) {
  FramebufferMap::iterator it = framebuffers_.find(client_id);
  if (it != framebuffers_.end()) {
    it->second->MarkAsDeleted();
    framebuffers_.erase(it);
  }
}

void Framebuffer::DoUnbindGLAttachmentsForWorkaround(GLenum target) {
  // Replace all attachments with the default Renderbuffer.
  for (AttachmentMap::const_iterator it = attachments_.begin();
       it != attachments_.end(); ++it) {
    glFramebufferRenderbufferEXT(target, it->first, GL_RENDERBUFFER, 0);
  }
}

void Framebuffer::AttachRenderbuffer(
    GLenum attachment, Renderbuffer* renderbuffer) {
  const Attachment* a = GetAttachment(attachment);
  if (a)
    a->DetachFromFramebuffer(this);
  if (renderbuffer) {
    attachments_[attachment] = scoped_refptr<Attachment>(
        new RenderbufferAttachment(renderbuffer));
  } else {
    attachments_.erase(attachment);
  }
  framebuffer_complete_state_count_id_ = 0;
}

void Framebuffer::AttachTexture(
    GLenum attachment, TextureRef* texture_ref, GLenum target,
    GLint level, GLsizei samples) {
  const Attachment* a = GetAttachment(attachment);
  if (a)
    a->DetachFromFramebuffer(this);
  if (texture_ref) {
    attachments_[attachment] = scoped_refptr<Attachment>(
        new TextureAttachment(texture_ref, target, level, samples, 0));
    texture_ref->texture()->AttachToFramebuffer();
  } else {
    attachments_.erase(attachment);
  }
  framebuffer_complete_state_count_id_ = 0;
}

void Framebuffer::AttachTextureLayer(
    GLenum attachment, TextureRef* texture_ref, GLenum target,
    GLint level, GLint layer) {
  const Attachment* a = GetAttachment(attachment);
  if (a)
    a->DetachFromFramebuffer(this);
  if (texture_ref) {
    attachments_[attachment] = scoped_refptr<Attachment>(
        new TextureAttachment(texture_ref, target, level, 0, layer));
    texture_ref->texture()->AttachToFramebuffer();
  } else {
    attachments_.erase(attachment);
  }
  framebuffer_complete_state_count_id_ = 0;
}

const Framebuffer::Attachment*
    Framebuffer::GetAttachment(
        GLenum attachment) const {
  AttachmentMap::const_iterator it = attachments_.find(attachment);
  if (it != attachments_.end()) {
    return it->second.get();
  }
  return NULL;
}

const Framebuffer::Attachment* Framebuffer::GetReadBufferAttachment() const {
  if (read_buffer_ == GL_NONE)
    return nullptr;
  return GetAttachment(read_buffer_);
}

bool FramebufferManager::GetClientId(
    GLuint service_id, GLuint* client_id) const {
  // This doesn't need to be fast. It's only used during slow queries.
  for (FramebufferMap::const_iterator it = framebuffers_.begin();
       it != framebuffers_.end(); ++it) {
    if (it->second->service_id() == service_id) {
      *client_id = it->first;
      return true;
    }
  }
  return false;
}

void FramebufferManager::MarkAttachmentsAsCleared(
    Framebuffer* framebuffer,
    RenderbufferManager* renderbuffer_manager,
    TextureManager* texture_manager) {
  DCHECK(framebuffer);
  framebuffer->MarkAttachmentsAsCleared(renderbuffer_manager,
                                        texture_manager,
                                        true);
  MarkAsComplete(framebuffer);
}

void FramebufferManager::MarkAsComplete(
    Framebuffer* framebuffer) {
  DCHECK(framebuffer);
  framebuffer->MarkAsComplete(framebuffer_state_change_count_);
}

bool FramebufferManager::IsComplete(
    Framebuffer* framebuffer) {
  DCHECK(framebuffer);
  return framebuffer->framebuffer_complete_state_count_id() ==
      framebuffer_state_change_count_;
}

}  // namespace gles2
}  // namespace gpu