Playing with walking turtle

turtle.red

Red [
  Date: 2018-10-21
]
tick: steps: 0
move: func [dir][
	set [rotation step] switch dir [
		left [[180 -32x0]] 
		up [[-90 0x-32]] 
		right [[0 32x0]] 
		down [[90 0x32]]
	] 
	if turn/2 <> rotation [
		;print ["turn/2:" turn/2 "rotation:" rotation]
		rot: switch/default turn/2 [
			180 [switch rotation [90 [-90] 0 [-180] -90 [turn/2: -180 90]]]
			-90 [either rotation = 180 [turn/2: 270 -90][negate -90 - rotation]]
			 90 [rotation - 90]
		][rotation]
	]

	;turn/2: rotation 
	;turtle/offset: turtle/offset + step
]
view/tight [
	size 320x320 
	on-key [move direction: event/key steps: steps + 1 turtle/rate: 8] 
	turtle: box 32x32 draw [
		turn: rotate 0 16x16 [
			pen gray 
			line-width 5 
			line-cap round 
			_head: line 20x15 26x15 
			_front-right: rotate 0 20x20 [line 20x20 21x24]
			_front-left: rotate 0 20x10 [line 20x10 21x6]
			_rear-right: rotate 0 9x20 [line 9x20 8x23] 
			_rear-left: rotate 0 9x10 [line 9x10 8x7]
			pen off 
			fill-pen brown 
			_shell: rotate 0 16x16 [ellipse 5x7 20x16]
		]
	] on-time [
		either turn/2 <> rotation [
			turn/2: turn/2 + (rot / 9)
		][
			tick: tick + 1
			either steps > 0 [
				if tick - 1 % 32 + 1 = 32 [steps: steps - 1]
				case [
					any [tick - 1 % 32 + 1 > 25 tick - 1 % 32 + 1 <= 9] [
						_front-right/2: _front-right/2 + 6
						_rear-right/2: _rear-right/2 - 6
						_front-left/2: _front-left/2 + 6
						_rear-left/2: _rear-left/2 - 6
					]
					tick - 1 % 32 + 1 > 9 [
						_front-right/2: _front-right/2 - 6
						_rear-right/2: _rear-right/2 + 6
						_front-left/2: _front-left/2 - 6
						_rear-left/2: _rear-left/2 + 6
					]
				]
				face/offset: face/offset + switch direction [
					left [-1x0] up [0x-1] right [1x0] down [0x1]
				]
			][
				face/rate: none
				tick: 0
			]
		]
	]
]