work in progress on z-buffer depth linerization shader

depth_linearization.glsl

float Znear = 1.0;
float Zfar = 20.0;
float Q = Zfar / ( Zfar - Znear );
float inv_Zfar = 1.0 / Zfar;
uniform sampler2D bgl_DepthTexture;

void main()
{
    // Sampling
    float depth = texture2D(bgl_DepthTexture,  gl_TexCoord[0].xy).r;
    // Linearization
    float z_e = inv_Zfar / (Q - depth);

    gl_FragColor = vec4(vec3(z_e), 1.0);
}