#version 430
#define SORT_SIZE 512
layout(std430, row_major) buffer ParticleDistances{
  float particle_distances[];
} ;
layout(std430, row_major) buffer AliveParticles1{
  uint alive_particles_1[];
} ;
#define HALF_SIZE (SORT_SIZE/2)
#define ITERATIONS (1024 < HALF_SIZE ? HALF_SIZE/1024 : 1)
#define NUM_THREADS (HALF_SIZE/ITERATIONS)
layout(local_size_x = 256, local_size_y = 1, local_size_z = 1) in ;
uniform int elements;
shared vec2 local_storage[SORT_SIZE];
void main();

void _GLSLTK_main_1(){
  uint global_base_index = ((gl_WorkGroupID.x * SORT_SIZE) + gl_LocalInvocationID.x);
  uint local_base_index = gl_LocalInvocationIndex;
  uint elements_in_thread_group = min(SORT_SIZE, (elements - (gl_WorkGroupID.x * SORT_SIZE)));
  for(uint i = 0; (i < (2 * ITERATIONS)); ++i){
    if(((gl_LocalInvocationIndex + (i * NUM_THREADS)) < elements_in_thread_group)){
      uint load_index = (global_base_index + (i * NUM_THREADS));
      local_storage[(local_base_index + (i * NUM_THREADS))] = vec2(particle_distances[load_index], float(alive_particles_1[load_index]));
    };
  };
  groupMemoryBarrier();
  barrier();
  for(uint merge_size = 2; (merge_size <= SORT_SIZE); merge_size = (merge_size * 2)){
    for(uint sub_size = (merge_size >> 1); (0 < sub_size); sub_size = (sub_size >> 1)){
      for(uint i = 0; (i < ITERATIONS); ++i){
        uint tmp_index = (gl_LocalInvocationIndex + (NUM_THREADS * i));
        uint index_low = (tmp_index & (sub_size - 1));
        uint index_high = (2 * (tmp_index - index_low));
        uint index = (index_low + index_high);
        uint candidate = (sub_size == (merge_size >> 1))? ((index_high + ((2 * sub_size) - 1)) - index_low) :(index_high + (index_low + sub_size));
        if((candidate < elements_in_thread_group)){
          vec2 a = local_storage[index];
          vec2 b = local_storage[candidate];
          if((b.x < a.x)){
            local_storage[index] = b;
            local_storage[candidate] = a;
          };
        };
        groupMemoryBarrier();
        barrier();
      };
    };
  };
  for(uint i = 0; (i < (2 * ITERATIONS)); ++i){
    if(((gl_LocalInvocationIndex + (i * NUM_THREADS)) < elements_in_thread_group)){
      uint load_index = (local_base_index + (i * NUM_THREADS));
      uint store_index = (global_base_index + (i * NUM_THREADS));
      particle_distances[store_index] = local_storage[load_index].x;
      alive_particles_1[store_index] = uint(local_storage[load_index].y);
    };
  };
}

void main(){
  _GLSLTK_main_1();
}