Check out Alice Chess, our featured variant for June, 2024.

Enter Your Reply

The Comment You're Replying To
H. G. Muller wrote on Thu, Jan 14, 2021 09:22 AM UTC in reply to Aurelian Florea from 06:57 AM:

I must admit that this would currently also not work in presets generated by the Play-Testing Applet. At least for highlighting purposes: it also fails to update the 'last moved piece' when it tenttatively makes the move that might have to be highlighted in order to test if it exposes the King to capture. But if you decide to use the Applet-generated code, I can fix that.

To speed up fully-legal highlighting, I use a short-cut: Instead of trying all possible opponent moves to see if they capture the King, I only try those that might have been affected by the move of which we want to judge the legality. To that end it first marks all squares attaced by the opponent in the original position with its own King removed, and for every piece it makes a list of moves (origin and direction) that they obstruct. It also makes a list of pre-existing checking moves. After trying a move, it then only reruns the pre-existing checks in the resulting position (to see whether these are now resolved), plus the moves that were blocked by the moved piece (to check whether that piece was pinned). And for King moves it tests whether these go to a square that was marked as being under attack.

I suppose it would have to rerun all moves of an imitator too, because these are also affected by the preceding move. (And do the attacked-squares test in the initial position while imitating a King.)


Edit Form
Conduct Guidelines
This is a Chess variants website, not a general forum.
Please limit your comments to Chess variants or the operation of this site.
Keep this website a safe space for Chess variant hobbyists of all stripes.
Because we want people to feel comfortable here no matter what their political or religious beliefs might be, we ask you to avoid discussing politics, religion, or other controversial subjects here. No matter how passionately you feel about any of these subjects, just take it someplace else.
Avoid Inflammatory Comments
If you are feeling anger, keep it to yourself until you calm down. Avoid insulting, blaming, or attacking someone you are angry with. Focus criticisms on ideas rather than people, and understand that criticisms of your ideas are not personal attacks and do not justify an inflammatory response.
Quick Markdown Guide

By default, new comments may be entered as Markdown, simple markup syntax designed to be readable and not look like markup. Comments stored as Markdown will be converted to HTML by Parsedown before displaying them. This follows the Github Flavored Markdown Spec with support for Markdown Extra. For a good overview of Markdown in general, check out the Markdown Guide. Here is a quick comparison of some commonly used Markdown with the rendered result:

Top level header: <H1>

Block quote

Second paragraph in block quote

First Paragraph of response. Italics, bold, and bold italics.

Second Paragraph after blank line. Here is some HTML code mixed in with the Markdown, and here is the same <U>HTML code</U> enclosed by backticks.

Secondary Header: <H2>

  • Unordered list item
  • Second unordered list item
  • New unordered list
    • Nested list item

Third Level header <H3>

  1. An ordered list item.
  2. A second ordered list item with the same number.
  3. A third ordered list item.
Here is some preformatted text.
  This line begins with some indentation.
    This begins with even more indentation.
And this line has no indentation.

Alt text for a graphic image

A definition list
A list of terms, each with one or more definitions following it.
An HTML construct using the tags <DL>, <DT> and <DD>.
A term
Its definition after a colon.
A second definition.
A third definition.
Another term following a blank line
The definition of that term.