Log / Linear Z-Buffer shadow map - c++

Question

The problem is that artifacts appear in the shadows at a great distance. I want to try to make a logarithmic depth buffer, but I don’t understand where it should be done and how ... I use point light method for omnidirectional shadow maps
Vertex shader:
#version 460 core
layout (location = 0) in vec3 aPos;
uniform mat4 model;
uniform float zCoef;
//out vec4 pos;
void main() {
gl_Position = model * vec4(aPos, 1.0f);
// gl_Position.z = log2(max(1e-6, gl_Position.w + 1.0)) * zCoef - 1.0;
// gl_Position.z *= gl_Position.w;
}
Geometry shader:
#version 460 core
layout (triangles) in;
layout (triangle_strip, max_vertices = 18) out;
uniform mat4 shadowMatrices[6];
uniform float zCoef;
out vec4 FragPos; // FragPos from GS (output per emitvertex)
void main()
{
for(int face = 0; face < 6; ++face)
{
gl_Layer = face; // встроенная переменная, указывающая на то, какую грань мы рендерим
for(int i = 0; i < 3; ++i) // для каждой вершины треугольника
{
FragPos = gl_in[i].gl_Position;
gl_Position = shadowMatrices[face] * FragPos;
// gl_Position.z = log2(max(1e-6, gl_Position.w + 1.0)) * zCoef - 1.0;
// gl_Position.z *= gl_Position.w;
EmitVertex();
}
EndPrimitive();
}
}
Fragment shader:
#version 460 core
in vec4 FragPos;
uniform vec3 lightPos;
uniform float farPlane;
uniform float zCoef;
void main() {
float lightDistance = length(FragPos.xyz - lightPos);
lightDistance = lightDistance / farPlane;
gl_FragDepth = lightDistance;
}
Guys, pls help me,i tried to use the linearization depth, it didn't work too..