/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup gpu
 */

#pragma once

/**
 * Describes the load operation of a frame-buffer attachment at the start of a render pass.
 */
enum eGPULoadOp {
  /**
   * Clear the frame-buffer attachment using the clear value.
   */
  GPU_LOADACTION_CLEAR = 0,
  /**
   * Load the value from the attached texture.
   * Cannot be used with memoryless attachments.
   * Slower than `GPU_LOADACTION_CLEAR` or `GPU_LOADACTION_DONT_CARE`.
   */
  GPU_LOADACTION_LOAD,
  /**
   * Do not care about the content of the attachment when the render pass starts.
   * Useful if only the values being written are important.
   * Faster than `GPU_LOADACTION_CLEAR`.
   */
  GPU_LOADACTION_DONT_CARE,
};

/**
 * Describes the store operation of a frame-buffer attachment at the end of a render pass.
 */
enum eGPUStoreOp {
  /**
   * Do not care about the content of the attachment when the render pass ends.
   * Useful if only the values being written are important.
   * Cannot be used with memoryless attachments.
   */
  GPU_STOREACTION_STORE = 0,
  /**
   * The result of the rendering for this attachment will be discarded.
   * No writes to the texture memory will be done which makes it faster than
   * `GPU_STOREACTION_STORE`.
   * IMPORTANT: The actual values of the attachment is to be considered undefined.
   * Only to be used on transient attachment that are only used within the boundaries of
   * a render pass (ex.: Unneeded depth buffer result).
   */
  GPU_STOREACTION_DONT_CARE,
};

/**
 * Describes the state of a frame-buffer attachment during a sub-pass.
 *
 * NOTE: Until this is correctly implemented in all backend, reading and writing from the
 * same attachment will not work. Although there is no case where it would currently be useful.
 */
enum GPUAttachmentState {
  /** Attachment will not be written during rendering. */
  GPU_ATTACHEMENT_IGNORE = 0,
  /** Attachment will be written during render sub-pass. This also works with blending. */
  GPU_ATTACHEMENT_WRITE,
  /** Attachment is used as input in the fragment shader. Incompatible with depth on Metal. */
  GPU_ATTACHEMENT_READ,
};

enum eGPUFrontFace {
  GPU_CLOCKWISE,
  GPU_COUNTERCLOCKWISE,
};