Check out Atomic Chess, our featured variant for November, 2024.

Enter Your Reply

The Comment You're Replying To
H. G. Muller wrote on Thu, Apr 18 04:16 PM UTC in reply to Jean-Louis Cazaux from 02:46 PM:

Sorry, I was out of town for a few days, and had no time to figure out the answer on this one.

The presets you compare with were not automated through the PTA, so there is no reason why these should behave the same.

Are you sure the game ends when the King moves out of check? Normally an illegal move should not terminate the game; it should just be refused (in this case with the message you quote), and then through using the browser 'back' button you should be able to retry another move. This is also what happens if you insist moving a piece to a non-highlighted destination.

If this is the case the only thing that isn't working exactly as it should is the highlighting: the King jumps get highlighted even if they are forbidden because of check. But there is no way to exploit this; in the end legality is enforced by refusing the move.

The way the PTA-generated GAME code enforces 'not out of check' rules is by having the potentially forbidden moves generate e.p. rights on the square of origin. Using such a move then would allow the opponent to capture the moved piece (i.e. the King) en passant, making the move illegal.

Unfortunately the 'accelerated check test' used for determining the legality of the moves to highlight (in order to prevent this from becoming excruciatingly slow for large games) doesn't detect this: it generates all opponent moves from the current position to mark squares that are under attack on the board. And then only rejects King moves that go to such an attacked square. And in this case the problem is not that the destination is attacked, but that the origin is attacked.

I suppose I could solve this in the accelerated check test by suppressing the virginity of a King that is in check during the generation of the highlights.

[Edit] I now changed the move generator to suppress initial moves of a piece that should not move out of check, when it is in check during the accelerated check test. Please test if this solves the problem.


Edit Form

Comment on the page Bigorra

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.