gs:key-event

[electrifiedspam]

Could anyone post something or point me to an example where this is in use?

I am trying to make a simple snake game and I can do all of it except tell when a certain key is pressed.

Thank you in advance for your help.

Chris

[cormullion]

Try here

http://www.nodep.nl/downloads/newlisp/worm.lsp

[Lutz]

unfortunately worm.lsp is broken in versions 10.0 and after but the following works:

http://www.newlisp.org/code/ybrick.lsp

with added UP/DOWN for speed change.

[electrifiedspam]

Thank you all. I have made it this far.

Those examples helped my understand what was going on.
Thank you again.

Chris
----------------------------------------------------------------------------------------------------------------------
(set 'up 38)
(set 'down 40)
(set 'left 37)
(set 'right 39)
(set 'delay 20000)

(set-locale "C")
(load (append (env "NEWLISPDIR") "/guiserver.lsp"))
(gs:init)

(define (key-action id type code modifiers) (set 'KEY code) (println "key: " KEY))


;;Define the Gui
(gs:frame 'snakeGame 100 100 600 600 "New Snake Game")
(gs:canvas 'C)
(gs:set-background 'C gs:white)
(gs:fill-rect 'r 280 280 10 10 gs:red)
(gs:key-event 'C 'key-action)

(gs:add-to 'snakeGame 'C)
(gs:set-visible 'snakeGame true)

(while (gs:check-event delay)
;;required for key event
(gs:request-focus 'C)
;;Move Red Square
(cond ((= KEY up) (gs:move-tag 'r 0 -5) (set 'KEY 0))
((= KEY down) (gs:move-tag 'r 0 5 ) (set 'KEY 0))
((= KEY right) (gs:move-tag 'r 5 0) (set 'KEY 0))
((= KEY left) (gs:move-tag 'r -5 0) (set 'KEY 0))
)
(gs:update)
)

[cormullion]

it works on my computer too! :)

[electrifiedspam]

Is there a way in GS to get the color of a point on the canvas?

I was just going to check the colors in front of the head of the snake to know if there has been a collision.

Thank you.

Chris

[cormullion]

I don't think you can read pixels from a canvas (or write to them either). You'd probably have to keep a record of which areas have been painted so that you can test against them later.

[electrifiedspam]

Well, this is as far as I have gotten so far.

Problems:
1) Snake does not detect when it has hit itself.
2) 'Apples' can instantiate on the snake causing an effective end to game play.

I just thought that you all would like to see how far I have come with your help.

Thank you
Chris
------------------------------------------------------------------------------------------------------------------------
(set 'up 38)
(set 'down 40)
(set 'left 37)
(set 'right 39)
(set 'delay 60000)
(set 'x 280 'y 280)
(set 'xBound 570 'yBound 550)
(set 'SNAKE (list (list x y)))
(set 'applState false)
(set 'SCORE 0)

(set-locale "C")
(load (append (env "NEWLISPDIR") "/guiserver.lsp"))
(gs:init)

(define (key-action id type code modifiers) (set 'DIRECTION (if (= code up) "UP" (= code down) "DOWN" (= code right) "RIGHT" (= code left) "LEFT")))

(define (apple) (set 'xCord (* 10 (rand 50)) 'yCord (* 10 (rand 50)))(gs:fill-rect 'a xCord yCord 10 10 gs:red) (setq applState true) (obstruction xCord yCord))
(define (obstruction xapp yapp) (set 'APPPOS (list (list xapp yapp))))
(define (tail xPos yPos) (gs:fill-rect 'r xpos ypos 5 5 gs:white))
(define (snake CORD)
(setq SNAKE (append CORD SNAKE)))


;;Define the Gui
(gs:frame 'snakeGame 100 100 600 600 "New Snake Game")
(gs:canvas 'C)
(gs:set-background 'C gs:white)
(gs:fill-rect 'r x y 10 10 gs:green)
(println SNAKE)
(gs:key-event 'C 'key-action)

(gs:add-to 'snakeGame 'C)
(gs:set-visible 'snakeGame true)

(while (gs:check-event delay)
;;required for key event
(gs:request-focus 'C)

;;Move Red Square
(cond ((= DIRECTION "UP") (setq y (- y 10)) (snake (list (list x y))
(gs:fill-rect 'r x y 10 10 gs:green)))
((= DIRECTION "DOWN") (setq y (+ y 10)) (snake (list (list x y))
(gs:fill-rect 'r x y 10 10 gs:green)))
((= DIRECTION "RIGHT") (setq x (+ x 10)) (snake (list (list x y))
(gs:fill-rect 'r x y 10 10 gs:green)))
((= DIRECTION "LEFT") (setq x (- x 10)) (snake (list (list x y))
(gs:fill-rect 'r x y 10 10 gs:green)))
)
;;check border
(cond ((>= (first (first SNAKE)) 575) (setq DIRECTION "UP"))
((>= (last (first SNAKE)) 555) (setq DIRECTION "RIGHT"))
((= (first (first SNAKE)) 0) (setq DIRECTION "DOWN"))
((= (last (first SNAKE)) 0) (setq DIRECTION "LEFT"))
)
;;draw new apple
(if (= applState false) (apple))
;;colission detection
(cond
((= (first SNAKE) (first APPPOS)) (set 'applState false 'SCORE (inc SCORE))(println SCORE))
)
(if (index (fn (X) (= (first SNAKE) x)) (rest SNAKE)) (exit))
;;erase end of tail
(if (and (= applState true) (> (length SNAKE) 1)) ((gs:fill-rect 'r (first (last SNAKE)) (last (last SNAKE)) 10 10 gs:white) (setq SNAKE (chop SNAKE))))
(gs:update)
)

[electrifiedspam]

I have found a fix for the aforementioned problems.

I won't post the code again until I have some major revisions.

Thank you for your help
Chris

[Lutz]

Each time you call gs:fill-rect a new rectangle object is created in Guiserver and eventually you will run out of memory, if you play long enough ;-)

You animate by using gs:xxx-tag operations on shapes created with gs:fill-yyy or gs:draw-yyy. You could do a gs:delete-tag on the old tail piece, just painting it white will not delete it.