From: Mauro Aranda <maurooaranda@gmail.com>
To: 20579@debbugs.gnu.org
Subject: bug#20579: 24.4; Pong bat loses 1/3rd of its length if the ball hits it too quickly
Date: Wed, 7 Aug 2019 12:03:49 -0300 [thread overview]
Message-ID: <CABczVwfftHKzNHEiqR=akr8p5no9vXa0PWUny_Hk+OqjDraNOA@mail.gmail.com> (raw)
In-Reply-To: <5554F04D.6030200@creativecommons.org>
[-- Attachment #1.1: Type: text/plain, Size: 234 bytes --]
tags 20579 patch
quit
Hello.
I can reproduce this bug in Emacs 25.3, Emacs 26.2 and the current
master.
I attach a patch that fixes this bug, and also does some improvement in
the collision detection of pong.
Best regards,
Mauro.
[-- Attachment #1.2: Type: text/html, Size: 296 bytes --]
[-- Attachment #2: 0001-Fix-pong-collision-detection.patch --]
[-- Type: text/x-patch, Size: 4119 bytes --]
From d1b442f4371193b03af4c6e05119d87fc8512f31 Mon Sep 17 00:00:00 2001
From: Mauro Aranda <maurooaranda@gmail.com>
Date: Tue, 6 Aug 2019 21:48:41 -0300
Subject: [PATCH] Fix pong collision detection
* lisp/play/pong.el (pong-update-game): If the ball hit the bat where
bats are positioned, draw again the bat cell in the old ball
position. (Bug#20579).
Also, avoid changing the direction of the ball right after hitting the
bats, and improve the collision detection against the borders.
---
lisp/play/pong.el | 83 ++++++++++++++++++++++++++++++++-----------------------
1 file changed, 49 insertions(+), 34 deletions(-)
diff --git a/lisp/play/pong.el b/lisp/play/pong.el
index 555c193..759dbb4 100644
--- a/lisp/play/pong.el
+++ b/lisp/play/pong.el
@@ -349,46 +349,61 @@ pong-update-game
(let ((old-x pong-x)
(old-y pong-y))
-
+ ;; Erase the last ball position.
+ (when (and (> old-y 0)
+ (< old-y (- pong-height 1)))
+ ;; If the ball hit the bat in the column where bats are positioned,
+ ;; and therefore changed its x direction, draw again the bat cell.
+ (if (or (and (= old-x 2) (< 0 pong-xx))
+ (and (= old-x (- pong-width 3)) (> 0 pong-xx)))
+ (gamegrid-set-cell old-x old-y pong-bat)
+ (gamegrid-set-cell old-x old-y pong-blank)))
+
+ ;; Update the ball position.
(setq pong-x (+ pong-x pong-xx))
- (setq pong-y (+ pong-y pong-yy))
-
- (if (and (> old-y 0)
- (< old-y (- pong-height 1)))
- (gamegrid-set-cell old-x old-y pong-blank))
-
+ ;; If the ball would go out of bounds, put it against the border.
+ (cond
+ ((<= (+ pong-y pong-yy) 0)
+ (setq pong-yy (- pong-yy))
+ (setq pong-y 1))
+ ((>= (+ pong-y pong-yy) (- pong-height 1))
+ (setq pong-yy (- pong-yy))
+ (setq pong-y (- pong-height 2)))
+ (t
+ (setq pong-y (+ pong-y pong-yy))
+ ;; Check if the ball is against the border now,
+ ;; and change the y direction if it is.
+ (when (or (<= pong-y 1) (>= pong-y (- pong-height 2)))
+ (setq pong-yy (- pong-yy)))))
+
+ ;; Draw the ball in its new position.
(if (and (> pong-y 0)
(< pong-y (- pong-height 1)))
(gamegrid-set-cell pong-x pong-y pong-ball))
+ ;; Hit bat, score a goal, or nothing.
(cond
- ((or (= pong-x 3) (= pong-x 2))
- (if (and (>= pong-y pong-bat-player1)
- (< pong-y (+ pong-bat-player1 pong-bat-width)))
- (and
- (setq pong-yy (+ pong-yy
- (cond
- ((= pong-y pong-bat-player1) -1)
- ((= pong-y (1+ pong-bat-player1)) 0)
- (t 1))))
- (setq pong-xx (- pong-xx)))))
-
- ((or (= pong-x (- pong-width 4)) (= pong-x (- pong-width 3)))
- (if (and (>= pong-y pong-bat-player2)
- (< pong-y (+ pong-bat-player2 pong-bat-width)))
- (and
- (setq pong-yy (+ pong-yy
- (cond
- ((= pong-y pong-bat-player2) -1)
- ((= pong-y (1+ pong-bat-player2)) 0)
- (t 1))))
- (setq pong-xx (- pong-xx)))))
-
- ((<= pong-y 1)
- (setq pong-yy (- pong-yy)))
-
- ((>= pong-y (- pong-height 2))
- (setq pong-yy (- pong-yy)))
+ ((and (or (= pong-x 3) (= pong-x 2))
+ (> 0 pong-xx) ; Collide with the bat if headed towards it.
+ (>= pong-y pong-bat-player1)
+ (< pong-y (+ pong-bat-player1 pong-bat-width)))
+ (setq pong-yy (+ pong-yy
+ (cond
+ ((= pong-y pong-bat-player1) -1)
+ ((= pong-y (1+ pong-bat-player1)) 0)
+ (t 1))))
+ (setq pong-xx (- pong-xx)))
+
+ ((and (or (= pong-x (- pong-width 4)) (= pong-x (- pong-width 3)))
+ (< 0 pong-xx) ; Collide with the bat if headed towards it.
+ (>= pong-y pong-bat-player2)
+ (< pong-y (+ pong-bat-player2 pong-bat-width)))
+ (setq pong-yy (+ pong-yy
+ (cond
+ ((= pong-y pong-bat-player2) -1)
+ ((= pong-y (1+ pong-bat-player2)) 0)
+ (t 1))))
+ (setq pong-xx (- pong-xx)))
((< pong-x 1)
(setq pong-score-player2 (1+ pong-score-player2))
--
2.7.4
next prev parent reply other threads:[~2019-08-07 15:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-14 18:58 bug#20579: 24.4; Pong bat loses 1/3rd of its length if the ball hits it too quickly Matt Lee
2019-08-07 15:03 ` Mauro Aranda [this message]
2019-08-10 8:52 ` Eli Zaretskii
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CABczVwfftHKzNHEiqR=akr8p5no9vXa0PWUny_Hk+OqjDraNOA@mail.gmail.com' \
--to=maurooaranda@gmail.com \
--cc=20579@debbugs.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.