____________________

                           ISOMETRIC GRAMMARS

                              Leon Rische
                          ____________________


                            [2019-12-20 Fri]


Table of Contents
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1. Introduction
2. Transformation
3. Iteration 1
4. DONE Implement repeat function
5. DONE Bounds check be adding cuboid to grid
6. DONE Allow isize for positions
7. TODO Remove random cuboids from image
8. DONE Bounding box f list of cuboids
9. TODO bounded + randomly placed translate repeat





1 Introduction
==============

  This post extends the ideas presented in [Isometric Snowflakes] adding
  other transformations on cuboids.

  To do so, transformations are combined in (randomly generated) groups,
  then used to generate cuboids to add to the image.


[Isometric Snowflakes] <file:isometric_snowflakes.org>


2 Transformation
================

  - Swapping axes
  - Mirroring along an axis


3 Iteration 1
=============

  ,----
  | (defun plt-swap-random-both (obj)
  |   (plt-choice
  |    (plt-swap-xy-both obj)
  |    (plt-swap-xz-both obj)
  |    (plt-swap-yz-both obj)))
  |
  | (defun plt-mirror-random-both (obj)
  |   (plt-choice
  |    (plt-mirror-x-at-both obj 64)
  |    (plt-mirror-x-at-both obj 64)
  |    (plt-mirror-x-at-both obj 64)))
  |
  | (defun plt-translate-repeat-random (obj)
  |   (let ((times (plt-random-in-range 2 10))
  |         (step (plt-random-in-range 2 10)))
  |     (plt-choice
  |      (plt-translate-repeat-x obj step times)
  |      (plt-translate-repeat-y obj step times)
  |      (plt-translate-repeat-z obj step times))))
  |
  | (defun plt-ig-random (obj)
  |   (plt-choice
  |    (plt-ig-random (plt-mirror-random-both obj))
  |    (plt-ig-random (plt-swap-random-both obj))
  |    (plt-ig-random (plt-swap-random-both obj))
  |    (plt-ig-random (plt-swap-random-both obj))
  |    (plt-ig-random (plt-translate-repeat-random obj))
  |    (plt-ig-random (plt-translate-repeat-random obj))
  |    (plt-ig-random (plt-translate-repeat-random obj))
  |    obj
  |    obj
  |    obj))
  |
  | (let ((revision (format-time-string "%FT%H:%M:%S")))
  |   (dotimes (_i 100)
  |     (let* ((seed (plt-random-seed))
  |            (caption (vector (format "0x%s" seed))))
  |       (random seed)
  |       (let* ((grid-size 128)
  |              (n-cuboids (plt-random-pow2 1 4))
  |              (grid (plt-make-grid grid-size)))
  |         (dotimes (_ n-cuboids)
  |               (->
  |                (plt-random-iso-cuboid
  |                 (plt-random-pow2-size 0 6)
  |                 grid-size)
  |                (plt-ig-random)
  |                (plt-grid-add grid)))
  |         (plt-grid-to-image-bw
  |          grid
  |          (vector 32.0 32.0)
  |          (concat dir "/" revision "/" seed ".svg"))))))
  `----


4 DONE Implement repeat function
================================


5 DONE Bounds check be adding cuboid to grid
============================================


6 DONE Allow isize for positions
================================


7 TODO Remove random cuboids from image
=======================================


8 DONE Bounding box f list of cuboids
=====================================


9 TODO bounded + randomly placed translate repeat
=================================================

  generate, bb, move to origin, translate repeat, randomly place