anchor.diff:                          &key
                             (pos (v! 0 0))
                             (centered t)
  -                          (flip-uvs-vertically nil))
  +                          (flip-uvs-vertically nil)
  +                          (color-scale (v! 1 1 1 1)))
     (let* ((size (v! (texture-base-dimensions (sampler-texture sampler))))
            (vp-size (viewport-resolution (current-viewport)))
            (ratio (v2:/ size vp-size))
  
positive.code:              :mat (m3:rotation-x (radians 90))
               :tex sampler
               :uv-mult (v! 1 -1)
               :transform (calc-trans (v! 0 1.5 0)))
        (map-g #'draw-cube-face-pipeline (get-gpu-quad)
               :mat (m3:rotation-y (radians 90))
               :tex sampler
               :uv-mult (v! -1 1)
               :transform (calc-trans (v! -1 0.5 0)))
        (map-g #'draw-cube-face-pipeline (get-gpu-quad)
               :mat (m3:rotation-y (radians -90))
               :tex sampler
               :uv-mult (v! -1 1)
               :transform (calc-trans (v! 1 0.5 0)))
        (map-g #'draw-cube-face-pipeline (get-gpu-quad)
               :mat (m3:rotation-x (radians 180))
               :tex sampler
               :uv-mult (v! 1 -1)
               :transform (calc-trans (v! 0 0.5 0)))
        (map-g #'draw-cube-face-pipeline (get-gpu-quad)
               :mat (m3:rotation-x (radians -90))
               :tex sampler
               :uv-mult (v! 1 -1)
               :transform (calc-trans (v! 0 -0.5 0)))
        (map-g #'draw-cube-face-pipeline (get-gpu-quad)
               :mat (m3:rotation-x (radians 0))
               :tex sampler
               :uv-mult (v! 1 -1)
               :transform (calc-trans (v! 0 -1.5 0))))))
  
  ;;------------------------------------------------------------
  
  (defun %draw-sampler (sampler pos-vec2 rotation scale flip-uvs-vertically)
    (let* ((tex (sampler-texture sampler))
           (tex-res (resolution tex))
           (win-res (resolution (current-viewport)))
  
negative.code:     (map-g #'draw-texture-pipeline (get-gpu-quad)
             :tex sampler
             :transform transform
             :uv-y-mult (if flip-uvs-vertically -1s0 1s0) ;; this is a bug as it samples outside of texture
             :color-scale color-scale)))
  
  (defun rotated-rect-size (size-v2 φ)
    ;; returns width & height
  