matrix – Remodeling 3d level for depth testing

I’ve a ray and its course is (o,d). Multiply it by the mannequin matrix to rotate the mannequin.

o = uCamera.xyz, d = GenRay();
o = vec3(uModel * vec4(o,1));
d = vec3(uModel * vec4(d,0));

Then beam, RayMarchLeaf(o, d, t, coloration, regular); the place get the place vec3 t of the collision of the beam. (in mannequin coordinates).
Then traslate t to world coordinates :

t = vec3(inverse(uModel) * vec4(t,1)); // map to world pos;

okay, we have now a 3d digital camera coordinate and a degree. For Depth worth, we will use size(uCamera.xyz - t), however this isn’t correct. My digital camera is transferring and rotating in 3d area.
How you can correct calculate depth worth to retailer in texture?