/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree.
 */

#version 450 core

#define PRECISION ${PRECISION}

layout(std430) buffer;

#include "indexing_utils.h"

layout(set = 0, binding = 0, ${IMAGE_FORMAT[DTYPE]}) uniform PRECISION restrict writeonly ${IMAGE_T[NDIM][DTYPE]} image_out;
layout(set = 0, binding = 1) uniform PRECISION sampler3D image_in;

layout(set = 0, binding = 2) uniform PRECISION restrict OutLimits {
  ivec3 out_limits;
};

layout(set = 0, binding = 3) uniform PRECISION restrict Sizes {
  ivec4 sizes;
};

layout(set = 0, binding = 4) uniform PRECISION restrict SelectVal {
  // data.x: index along batch dim to select
  // data.y: number of batches
  // data.z: number of texels per batch
  // data.w: unused
  ivec4 select_info;
};

layout(local_size_x_id = 0, local_size_y_id = 1, local_size_z_id = 2) in;

void main() {
  const int num_batches = select_info.y;
  const int num_texel_per_batch = select_info.z;
  const int index = select_info.x;

  const ivec3 pos = ivec3(gl_GlobalInvocationID);

  if (any(greaterThanEqual(pos, out_limits))) {
    return;
  }

  const uint src_pos_z = (num_texel_per_batch * index) + pos.z;
  imageStore(
      image_out, pos, texelFetch(image_in, ivec3(pos.x, pos.y, src_pos_z), 0));
}