// Copyright (c) 2011 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/vertex_attrib_manager.h"

#include <list>

#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "build/build_config.h"
#define GLES2_GPU_SERVICE 1
#include "gpu/command_buffer/common/gles2_cmd_format.h"
#include "gpu/command_buffer/common/gles2_cmd_utils.h"
#include "gpu/command_buffer/service/gl_utils.h"

namespace gpu {
namespace gles2 {

VertexAttribManager::VertexAttribInfo::VertexAttribInfo()
    : index_(0),
      enabled_(false),
      size_(4),
      type_(GL_FLOAT),
      offset_(0),
      normalized_(GL_FALSE),
      gl_stride_(0),
      real_stride_(16),
      list_(NULL) {
  value_.v[0] = 0.0f;
  value_.v[1] = 0.0f;
  value_.v[2] = 0.0f;
  value_.v[3] = 1.0f;
}

VertexAttribManager::VertexAttribInfo::~VertexAttribInfo() {
}

bool VertexAttribManager::VertexAttribInfo::CanAccess(GLuint index) const {
  if (!enabled_) {
    return true;
  }

  if (!buffer_ || buffer_->IsDeleted()) {
    return false;
  }

  // The number of elements that can be accessed.
  GLsizeiptr buffer_size = buffer_->size();
  if (offset_ > buffer_size || real_stride_ == 0) {
    return false;
  }

  uint32 usable_size = buffer_size - offset_;
  GLuint num_elements = usable_size / real_stride_ +
      ((usable_size % real_stride_) >=
       (GLES2Util::GetGLTypeSizeForTexturesAndBuffers(type_) * size_) ? 1 : 0);
  return index < num_elements;
}

VertexAttribManager::VertexAttribManager()
    : max_vertex_attribs_(0),
      num_fixed_attribs_(0) {
}

VertexAttribManager::~VertexAttribManager() {
}

void VertexAttribManager::Initialize(uint32 max_vertex_attribs) {
  max_vertex_attribs_ = max_vertex_attribs;
  vertex_attrib_infos_.reset(
      new VertexAttribInfo[max_vertex_attribs]);
  for (uint32 vv = 0; vv < max_vertex_attribs; ++vv) {
    vertex_attrib_infos_[vv].set_index(vv);
    vertex_attrib_infos_[vv].SetList(&disabled_vertex_attribs_);
  }
}

bool VertexAttribManager::Enable(GLuint index, bool enable) {
  if (index >= max_vertex_attribs_) {
    return false;
  }
  VertexAttribInfo& info = vertex_attrib_infos_[index];
  if (info.enabled() != enable) {
    info.set_enabled(enable);
    info.SetList(enable ? &enabled_vertex_attribs_ : &disabled_vertex_attribs_);
  }
  return true;
}


}  // namespace gles2
}  // namespace gpu