// Copyright(c) 2019, NVIDIA CORPORATION. All rights reserved.
//
// 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.
//

#include "math.hpp"

namespace vk
{
  namespace su
  {
    glm::mat4x4 createModelViewProjectionClipMatrix(vk::Extent2D const& extent)
    {
      float fov = glm::radians(45.0f);
      if (extent.width > extent.height)
      {
        fov *= static_cast<float>(extent.height) / static_cast<float>(extent.width);
      }

      glm::mat4x4 model = glm::mat4x4(1.0f);
      glm::mat4x4 view = glm::lookAt(glm::vec3(-5.0f, 3.0f, -10.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, -1.0f, 0.0f));
      glm::mat4x4 projection = glm::perspective(fov, static_cast<float>(extent.width) / static_cast<float>(extent.height), 0.1f, 100.0f);
      glm::mat4x4 clip = glm::mat4x4(1.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 0.5f, 1.0f);   // vulkan clip space has inverted y and half z !
      return clip * projection * view * model;
    }
  }
}