Bug with the (clean) function about clojure-turtle HOT 4 CLOSED

So I actually have a fix to this but involved me adjusting some code that I don't know how it works so I'm not sure if I should submit it yet. My initial attempt was to simply add a (setxy) command in (clean), storing the x and y positions at the time (clean) was called and using those. This did remove the disjoint behavior, but caused the turtles triangle sprite to remain behind whenever a move command was called. While investigating I found that there was an invocation of (clean) in the (draw-turt-state) function. When this (clean) was removed the program immediately worked as intended with no problems. I do not know why this fixed it or if I broke something else in the process, but if a more elegant solution can not be found this one is available.

from clojure-turtle.

Good catch! I've been able to follow your commands easily and verify the behavior. It is a regression -- in other words, I don't recall happening previously. (Although, I can't seem to find a clean call inside a fn named similar to draw-turt-state.) The change in behavior is due to the way the turtle commands are drawn. Before, each command issued to the turtle would (or wouldn't) create a new line (segment) to be drawn from one point to another. We would store all lines to be drawn in a state container, and clean would empty the collection stored in that state container. Lines were correctly made to handle the statefulness of the turtle because they were created by wherever the turtle was and where it was going.

The work related to issue #2 prompted re-thinking how lines are defined (so as to handle shape fills, and color more generally), which triggered a re-thinking of how stateful info related to turtles are stored, displayed at the REPL, and rendered to the screen.

My current thought about what it would take to fix this issue is to add another field to the Turtle record, maybe :start-from, indicating from which point that the rendering of turtle's currently stored commands should start. In the draw-turtle-commands fn, there is an implicit assumption that all rendering must start at (0,0) because the loop state uses @(new-turtle) as-is. Meanwhile, rendering of the turtle sprite is correct because get-turtle-sprite ignores the turtle commands and just uses the turtle for its current position, and starts from there using (setxy (:x turt) (:y turt)) before creating the rest of the commands for drawing the turtle sprite. So I think clean should reset :start-from for the turtle it's dealing with, draw-turtle-commands should incorporate an initial setxy somehow (perhaps refactoring the (:commands turt) into a function that does so), and then the setxy call from get-turtle-sprite could be removed.

from clojure-turtle.

Hi, two things. One, I misspoke, the function is called get-turtle-sprite
"A helper function that draws the triangle that represents the turtle onto
the screen" and it occurs right before the second block of comments.
Second, using my hacked together version I have some samples of animation
using the wait function and would like to know if and where I should put
them.

On Wed, Mar 30, 2016 at 8:46 AM, Elango [email protected] wrote:

Good catch! I've been able to follow your commands easily and verify the
behavior. It is a regression -- in other words, I don't recall happening
previously. (Although, I can't seem to find a clean call inside a fn
named similar to draw-turt-state.) The change in behavior is due to the
way the turtle commands are drawn. Before, each command issued to the
turtle would (or wouldn't) create a new line (segment) to be drawn from one
point to another. We would store all lines to be drawn in a state
container, and clean would empty the collection stored in that state
container. Lines were correctly made to handle the statefulness of the
turtle because they were created by wherever the turtle was and where it
was going.

The work related to issue #2
#2 prompted re-thinking
how lines are defined (so as to handle shape fills, and color more
generally), which triggered a re-thinking of how stateful info related to
turtles are stored, displayed at the REPL, and rendered to the screen.

My current thought about what it would take to fix this issue is to add
another field to the Turtle record, maybe :start-from, indicating from
which point that the rendering of turtle's currently stored commands should
start. In the draw-turtle-commands fn, there is an implicit assumption
that all rendering must start at (0,0) because the loop state uses
@(new-turtle) as-is. Meanwhile, rendering of the turtle sprite is correct
because get-turtle-sprite ignores the turtle commands and just uses the
turtle for its current position, and starts from there using (setxy (:x
turt) (:y turt)) before creating the rest of the commands for drawing the
turtle sprite. So I think clean should reset :start-from for the turtle
it's dealing with, draw-turtle-commands should incorporate an initial
setxy somehow (perhaps refactoring the (:commands turt) into a function
that does so ), and then the setxy call from get-turtle-sprite could be
removed.

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#20 (comment)

from clojure-turtle.

The fix was implemented similar to what was discussed above. See PR #21 for details.

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