#version 410 core
out vec4 FragColor;

in vec3 TexCoords;

uniform samplerCube skybox;

float near = 0.02f;
float far = 100.0f;

float linearizeDepth(float depth)
{
    return (2.0 * near * far) / (far + near - (depth * 2.0 - 1.0) * (far - near));
}

float logisticDepth(float depth, float steepness, float offset)
{
    float zVal = linearizeDepth(depth);
    return (1 / (1 + exp(-steepness * (zVal - offset))));
}

void main()
{    
    float depth = logisticDepth(gl_FragCoord.z, 0.1f, 3.0f);
    FragColor = texture(skybox, TexCoords)* (1.0f - depth) + vec4(depth * vec3(0.0f, 0.109f, 0.447f), 1.0f);
}