#version 450
#extension GL_EXT_mesh_shader : enable
#extension GL_KHR_compute_shader_derivatives : require

layout(local_size_x = 4) in;
layout(derivative_group_linearKHR) in;

layout(binding = 0, std430) buffer Output {
    float dx;
} outData;

void main()
{
    float value = float(gl_LocalInvocationIndex);
    float localDx = dFdx(value);
    if (gl_LocalInvocationIndex == 0u)
        outData.dx = localDx;

    barrier();
    EmitMeshTasksEXT(1u, 1u, 1u);
}