(bloom:define-shader-function world2/v ((pos :vec3)
                                        &uniform
                                        (model :mat4)
                                        (view :mat4)
                                        (proj :mat4)
                                        (cell-type :int)
                                        (world world-data :ssbo :std-430))
  (with-slots (width height) world
    (let* ((map-size (vec2 width height))
           (coords (get-cell-coords world cell-type))
           (offset (vec3 (- (* coords 2) map-size) 0))
           (model-pos (vec3 (* model (vec4 (+ offset pos) 1)))))
      (values (* proj view (vec4 model-pos 1))
              model-pos))))

(bloom:define-shader-function generate-texture/wall ((frag-pos :vec3))
  (let* ((cracks-noise (umbra.noise:perlin (vec3 (* frag-pos 0.011))))
         (cracks (umbra.noise:cellular-fast (vec3 (* frag-pos 0.09))))
         (cracks (vec3 (- 1 (clamp (* 2.75 (pow cracks (* cracks-noise 5.5))) 0 1))))
         (stone-noise-1 (umbra.noise:perlin (vec3 (* frag-pos 0.38))))
         (stone-noise-2 (umbra.noise:simplex-perlin (vec3 (* frag-pos 0.18))))
         (stone-noise-3 (umbra.noise:cellular-fast (vec3 (* frag-pos 0.044))))
         (stone-noise-4 (umbra.noise:cellular-fast (vec3 (* frag-pos 0.054))))
         (stone (mix (vec3 (+ (* 0.28 stone-noise-1)
                              (* 0.35 stone-noise-2)
                              (* 0.45 stone-noise-3)))
                     (vec3 stone-noise-4)
                     0.35)))
    (values stone cracks)))

(bloom:define-shader-function world2/f ((frag-pos :vec3)
                                        &uniform
                                        (cell-type :int)
                                        (opacity :float))
  (umbra:mvlet* ((stone cracks (generate-texture/wall frag-pos)))
    (values (vec4 stone opacity)
            (vec4 cracks opacity))))