// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
 * @class   vtkOpenXRManagerGraphics

 * @brief   OpenXR manager graphics implementation
 *
 * Abstract class that defines the rendering backend used by vtkOpenXRManager.
 * It handles creation and management of the OpenXR rendering resources,
 * based on the rendering backend implemented by subclasses.
 *
 * @sa
 * vtkOpenXRManagerOpenGLGraphics vtkOpenXRManagerD3DGraphics
 */

#ifndef vtkOpenXRManagerGraphics_h
#define vtkOpenXRManagerGraphics_h

#include "vtkObject.h"
#include "vtkRenderingOpenXRModule.h" // For export macro

#include "vtkOpenXR.h" // For OpenXR types
#include <vector>      // For std::vector
VTK_ABI_NAMESPACE_BEGIN

class vtkOpenGLRenderWindow;

class VTKRENDERINGOPENXR_EXPORT vtkOpenXRManagerGraphics : public vtkObject
{
public:
  vtkTypeMacro(vtkOpenXRManagerGraphics, vtkObject);

  /**
   * Resize the internal vectors storing the color and depth swapchains.
   */
  virtual void SetNumberOfSwapchains(uint32_t viewCount) = 0;

  ///@{
  /**
   * Fill \p texture with the swapchain image for the specified eye. The image index should be
   * obtained beforehand using xrAcquireSwapchainImage.
   */
  virtual void GetColorSwapchainImage(uint32_t eyeIndex, uint32_t imgIndex, void* texture) = 0;
  virtual void GetDepthSwapchainImage(uint32_t eyeIndex, uint32_t imgIndex, void* texture) = 0;
  ///@}

  ///@{
  /**
   * Acquire swapchain images using xrEnumerateSwapchainImages and store them at the specified eye
   * index.
   */
  virtual void EnumerateColorSwapchainImages(XrSwapchain swapchain, uint32_t eyeIndex) = 0;
  virtual void EnumerateDepthSwapchainImages(XrSwapchain swapchain, uint32_t eyeIndex) = 0;
  ///@}

  /**
   * Acquire the number of images in the specified swapchain.
   */
  uint32_t GetChainLength(XrSwapchain swapchain);

  ///@{
  /**
   * Return the list of pixel formats supported by VTK. The first pixel format
   * in the list that is also supported by the runtime will be picked for rendering.
   */
  virtual const std::vector<int64_t>& GetSupportedColorFormats() = 0;
  virtual const std::vector<int64_t>& GetSupportedDepthFormats() = 0;
  ///@}

  /**
   * Create the graphics binding and store it in GraphicsBindings ptr.
   * It points to a XrGraphicsBindingXXX structure, depending on the
   * desired rendering backend.
   * \pre \p helperWindow must be initialized
   */
  virtual bool CreateGraphicsBinding(vtkOpenGLRenderWindow* helperWindow) = 0;

  /**
   * Return pointer to the backend-specific XrGraphicsBindingXXX structure
   * that is required to create the OpenXR session.
   */
  virtual const void* GetGraphicsBinding() = 0;

  /**
   * OpenXR requires checking graphics requirements before creating a session.
   * This uses a function pointer loaded with the selected graphics API extension.
   * /pre The XR instance and system id must be initialized
   */
  virtual bool CheckGraphicsRequirements(XrInstance instance, XrSystemId id) = 0;

  /**
   * Return the extension name to enable a specific rendering backend
   */
  virtual const char* GetBackendExtensionName() = 0;

protected:
  vtkOpenXRManagerGraphics() = default;
  ~vtkOpenXRManagerGraphics() override = default;

private:
  vtkOpenXRManagerGraphics(const vtkOpenXRManagerGraphics&) = delete;
  void operator=(const vtkOpenXRManagerGraphics&) = delete;
};

VTK_ABI_NAMESPACE_END
#endif