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jellysausage

Sat May 26, 2007 4:47 pm


Snake not appearing

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hmm... so ive been working on my snake game-thing-a-ma-bobber.... and my previous program was rather.. eh.. un-optimized so ive optimized the best i could. someone with more experience than me told me to have all the algorithms and all first, then the animating last... they also recommended using View.Update.. which i figured out how to incorperate into my program. anymway, the topic is rather self explanitory--my snake is not appearing. i havent set up all the stuff about hitting yourself and you die or hitting the wall and you die... but those are easy, im still focusing on getting the snake to:
-eat and grow eat and grow
-be able to turn multiple times without the program crashing

here's my code:

%SETSCREEN
setscreen ("graphics, nocursor,")
%DECLARING VARIABLES
var bod : array 1 .. 2, 1 .. 100 of int
%first coordinate determines if variable
%is the x or y coordinate
%"1" is x coordinate, "2" is y coordinate
%second coordinate determines how many
%x and y coordinate there are; how many
%body pieces there are
var food : array 1 .. 2 of int
var key : string (1)
var bodycount, randomdirection, speed : int
var gotfood : boolean
%ALGORITHMS
process movehead
    loop
        if hasch then
            getch (key)
            %right
            if key = KEY_RIGHT_ARROW then
                loop
                    bod (1, 1) += 1
                    bod (2, 1) := bod (2, 1)
                    exit when hasch
                end loop
                %left
            elsif key = KEY_LEFT_ARROW then
                loop
                    bod (1, 1) -= 1
                    bod (2, 1) := bod (2, 1)
                    exit when hasch
                end loop
                %up
            elsif key = KEY_UP_ARROW then
                loop
                    bod (1, 1) := bod (1, 1)
                    bod (2, 1) += 1
                    exit when hasch
                end loop
                %down
            elsif key = KEY_DOWN_ARROW then
                loop
                    bod (1, 1) := bod (1, 1)
                    bod (2, 1) -= 1
                    exit when hasch
                end loop
            end if
        end if
    end loop
end movehead
process movebody
    loop
        if bodycount > 0 then
            for j : 2 .. bodycount
                for i : 1 .. 2
                    bod (i, j) := bod (i, j - 1)
                    delay (50)
                end for
            end for
        end if
    end loop
end movebody
process foodonfield
    loop
        %putting food on field, only puts food if
        %snake has gotten food
        if (bod (1, 1) >= food (1) - 9 and food (1) + 9 >= bod (1, 1)) or (bod (2, 1) >= food (2) - 9 and food (2) + 9 >= bod (2, 1)) then
            gotfood := true
        end if
        if gotfood = true then
            randint (food (1), 15, maxx - 15)
            randint (food (2), 15, maxy - 15)
            bodycount += 1
            gotfood := false
        end if
    end loop
end foodonfield
%MAINSTREAM
%setting all beginning parameters
gotfood := false
bod (1, 1) := 300
bod (2, 1) := 200
speed := 50
bodycount := 0
food (1) := 400
food (2) := 100
%starting the snake off in a direction
randint (randomdirection, 1, 4)
if randomdirection = 1 then
    %if 1, then go right
    loop
        bod (1, 1) += 10
        bod (2, 1) := bod (2, 1)
        exit when hasch
    end loop
elsif randomdirection = 2 then
    %if 2, then go left
    loop
        bod (1, 1) -= 10
        bod (2, 1) := bod (2, 1)
        exit when hasch
    end loop
elsif randomdirection = 3 then
    %if 3, then go up
    loop
        bod (1, 1) := bod (1, 1)
        bod (2, 1) += 10
        exit when hasch
    end loop
else
    %if not 1,2,3, then down
    loop
        bod (1, 1) := bod (1, 1)
        bod (2, 1) -= 10
        exit when hasch
    end loop
end if
%Preparing all coordinates
fork movehead
fork movebody
fork foodonfield
%animating head and body
loop
    drawfilloval (bod (1, 1), bod (2, 1), 10, 10, blue)
    if bodycount > 0 then
        for j : 2 .. bodycount
            drawfilloval (bod (1, j), bod (2, j), 10, 10, blue)
        end for
    end if
    View.Update
    cls
    delay (speed)
end loop




one otherthing i was wondering about was that if i wanted my snake to wrap around onto the otherside.. well.. basically.. if i wanted the snake to come out from the opposite side if it were to pass through one of the walls.. the code would be something like...

if bod(1,1)>=635 then
bod(1,1):=0

etc etc etc with the x coordinate.. my second question is... how would i get the thing to continue moving? suggestions are much appreciated. ill update as needed


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DIIST

Sat May 26, 2007 5:27 pm


Re: Snake not appearing

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First you should probably consider creating a flexible array of record. It will make your life a lot easier. This will also help to add and delete elements easily. Perfect for a snake game. Look into it. 

type coord_2d :
    record
        x, y : int
    end record

var bod : flexible array 1 .. 0 of coord_2d
new bod,15 %makes the body size to be 15 elements

I was tracing your execution, and i found the blue line going berserk.Please refrain from using processes, they are hard to control and could result in a crash the way your using them. Just create a giant loop and use procedures. This will make our lives easier to debug. Cleaning your code might solve your problem!  :wink:


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Ultrahex

Sat May 26, 2007 5:48 pm


Re: Snake not appearing

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also using a class might help of type snake...

for example:


%% Point Record
type point :
    record
        x, y : int
    end record


%% Snake Object
class snake
    import point
    export construct, move, draw, setdir, current, grow

    %% Variables
    var dir : int
    var clr : int
    var current : point
    var tail : flexible array 1 .. 1 of point

    %% Creates Snake
    procedure construct (x : int, y : int, clr2 : int)
        dir := 0
        current.x := x;
        current.y := y;
        clr := clr2;
    end construct

    %% Moves Snake in Current Direction
    procedure move ()
        % dir = 0, means RIGHT
        % dir = 1, means UP
        % dir = 2, means LEFT
        % dir = 3, means DOWN
        if (dir = 0) then
            current.x += 1
        elsif (dir = 1) then
            current.y += 1
        elsif (dir = 2) then
            current.x -= 1
        elsif (dir = 3) then
            current.y -= 1
        end if

        % Move Tail Element Down One, Overwriting End Tail Peice
        for i : 2 .. upper (tail)
            tail (i - 1) := tail (i)
        end for
        tail (upper (tail)) := current
    end move

    %% Makes Snake Grow
    procedure grow ()
        new tail, upper (tail) + 1
        for i : 1 .. upper (tail)-1
            tail (i + 1) := tail (i)
        end for
    end grow

    %% Sets Snakes Direction
    procedure setdir (n : int)
        dir := n mod 4
    end setdir

    %% Draws Snake and its Tail
    procedure draw ()
        for i : 1 .. upper (tail)
            drawfilloval (tail (i).x * 10, tail (i).y * 10, 5, 5, clr)
        end for
    end draw

end snake

var mainSnake : ^snake
new mainSnake
mainSnake -> construct (10, 10, brightgreen)

var chars : array char of boolean
setscreen ("offscreenonly")
loop
    % DRAW BLACK BACKGROUND
    drawfillbox(0,0,800,600,black)

    % MOVE AND DRAW SNAKE
    mainSnake -> move ()
    mainSnake -> draw ()

    % DRAW APPLE AND CHECK IF PLAY HIT IT
    drawfilloval (15 * 10, 15 * 10, 5, 5, brightred)
    if (mainSnake -> current.x = 15 and mainSnake -> current.y = 15) then
        mainSnake -> grow ()
    end if

    % PLAYER INPUT
    Input.KeyDown (chars)
    if (chars ('a')) then
        mainSnake -> setdir (2)
    elsif (chars ('d')) then
        mainSnake -> setdir (0)
    elsif (chars ('w')) then
        mainSnake -> setdir (1)
    elsif (chars ('s')) then
        mainSnake -> setdir (3)
    end if

    % UPDATE SCREEN
    delay (50)
    View.Update
    cls
end loop



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jellysausage

Thu May 31, 2007 9:51 pm


Re: Snake not appearing

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AHA! it works!


setscreen ("graphics, nocursor,offscreenonly")
%DECLARING VARIABLES
var bodyx, bodyy : flexible array 1 .. 0 of int
var curx, cury : int := 0
var bodyspeed : int := 10
var food : array 1 .. 2 of int
var key, snakemenu : string (1)
var bodycount, randomdirection, speed, t : int
var direction : string
var death : boolean
proc right
    direction := "right"
    bodyx (1) += bodyspeed
    bodyy (1) := bodyy (1)
end right
proc left
    direction := "left"
    bodyx (1) -= bodyspeed
    bodyy (1) := bodyy (1)
end left
proc up
    direction := "up"
    bodyx (1) := bodyx (1)
    bodyy (1) += bodyspeed
end up
proc down
    direction := "down"
    bodyx (1) := bodyx (1)
    bodyy (1) -= bodyspeed
end down
proc foodonfield
    %putting food on field, only puts food if
    %snake has gotten food
    if bodyx (1) >= food (1) - 20 and bodyx (1) = food (2) - 20 and food (2) + 20 >= bodyy (1) then
        randint (food (1), 50, maxx - 50)
        randint (food (2), 50, maxy - 50)
        new bodyx, bodycount + 1
        new bodyy, bodycount + 1
        bodycount += 1
        bodyx (bodycount) := curx
        bodyy (bodycount) := cury
    end if
end foodonfield
%ALGORITHMS
proc movehead
    if hasch then
        getch (key)
        %right
        if key = KEY_RIGHT_ARROW and direction ~= "left" then
            right
            %left
        elsif key = KEY_LEFT_ARROW and direction ~= "right" then
            left
            %up
        elsif key = KEY_UP_ARROW and direction ~= "down" then
            up
            %down
        elsif key = KEY_DOWN_ARROW and direction ~= "up" then
            down
        end if
    else
        if direction = "up" then
            up
        elsif direction = "down" then
            down
        elsif direction = "right" then
            right
        elsif direction = "left" then
            left
        end if
    end if
end movehead
proc movebody
    curx := bodyx (bodycount)
    cury := bodyy (bodycount)
    if bodycount > 1 then
        for decreasing j : bodycount .. 2
            bodyx (j) := bodyx (j - 1)
            bodyy (j) := bodyy (j - 1)
        end for
    end if
end movebody
%player lost
proc lose
    if bodyx (1) >= maxx - 10 or bodyx (1) = maxy - 10 or bodyy (1)  1 then
        for j : 2 .. bodycount
            drawfilloval (bodyx (j), bodyy (j), 10, 10, blue)
        end for
    end if
    %Drawing food
    drawfilloval (food (1), food (2), 5, 5, red)
    View.Update
    delay (speed)
    cls
    if bodyx (1) >= maxx - 10 or bodyx (1) = maxy - 10 or bodyy (1)