depth_texture how to?

i'm trying

float d = texture(DEPTH_TEXTURE, UV).r;
ALBEDO.rgb = vec3(d, 0, 0);

and

float d = texture(DEPTH_TEXTURE, SCREEN_UV).r;

but everything is red. how to sample it in a right way?

It's because you are setting the albedo to only use the red channel.

If you do this it should work:

ALBEDO.rgb = vec3(d);

This will set all color channels to the same color giving you a grayscale image.

Note you will still have to transform the depth either to linear or adjust it to get a usable value.