How to take a "snapshot" of the XY coordinates to fire a bullet from an oval

[vapour99]

I am currently coding a SHUMP (spaceship shooter) game for my Grade 10 coding class and have encountered a simple problem:
When I move the ship, the bullets shot from the ship move as well.
The game is in its very early stages with simple titles and animations, but I need to solve this problem before I can continue programming the logic part of the game.

here is the code:

code:

var win, win2 : int var message : string var keyup : real var count : real var chars : array char of boolean var x1, x2, y1, y2, xb1, yb1 : int var x3, x4, y3, y4 : int var clr : int var shot : int var mx, my, button : int var boomy1, boomx1, boomy2, boomx2 : int var continue : string win := Window.Open ("position:middle,center, graphics: 640;800, Title: pauls moveoval") View.Set ("offscreenonly") x1 := 320 y1 := 20 x2 := 20 y2 := 20 clr := 2 boomx1 := 1 boomy1 := 1 process oval1     Draw.FillOval (x1, y1, x2, y2, 1) end oval1 process bullet %need to take a snapshot of the x/y cordinates of the mouse and fire a bullet straight up without (so mouse wont move bullet) ALSO NEEDS TO STOP FLASHING (viewupdate)     xb1 := mx     yb1 := my     shot := 1     for a : 1 .. 1000         drawfilloval (xb1, yb1 + a, 10, 10, brightred)         delay (1)         drawfilloval (yb1, yb1 + a, 10, 10, 0)     end for end bullet put "Welcome to Paul's Space shooter" put " " put " Mouse Rclick = shoot" put " Mouse = movment" put " " put "type y to play, n to quit" View.Update get continue if continue = "n"         then     Window.Close (win) end if loop     shot := 0     if continue = "n"             then         exit     end if     mousewhere (mx, my, button)     Draw.FillOval (mx, my, x2, y2, 1)     if button = 1 then         fork bullet     end if     if y1 >= 800             then         y1 := 800     end if     if x1 >= 640             then         x1 := 640     end if     if x1 <= 0             then         x1 := 0     end if     if y1 <= 0             then         y1 := 0     end if     View.Update     cls     Draw.FillOval (mx, my, x2, y2, 1)     if shot = 1 then         drawfilloval (xb1, yb1, 10, 10, brightred)     end if end loop win2 := Window.Open ("position:middle,center, graphics: 200;10, Title: bye!") put "thx for playing!" delay (1000) Window.Close (win2)

I also have a minor problem with View.Update on the "bullets" (flashing)

Any help given to a "newbe" programmer is much appreciated. I hope to contribute to the community as I learn.
-Regards; paul

[TheWanderer]

very good start (' ')b

looks like you're only keeping track of the bullets' x location with a single variable

solution contains many things to look into:
- you'll have to set a limit of bullets to be able to be shot from the ship
- you'll have to set a delay between firing a bullet, otherwise you'll start lagging for the next idea

- set up an array up to the limit of bullets that will keep track of bullet locations
- add to this array when the ship fires

its a little difficult for gr 10, but if you're determined, its not that hard to figure out in the end.
i think the major problem you'll encounter is going beyond array limits

another solution for you is to create just one bullet that moves very fast
keep track of its location separate from your ship position. but it'd be very boring right? XD

yes.. easy takes away from cool XD

[vapour99]

I am going to have to use the array option as a delay in the process halts the entire program and a delay in the if statements with the forks will create delays in the entire program is the key is pressed

Ill look into Arrays then.

You mention keeping track of a bullets position seperate from the ships position; how are you doing that without moving the ship as well?

[Insectoid]

INstead of a delay, use a counter. Every time the game loops, the counter goes down by one. when it reches zero, reset it and fire another bullet!

[vapour99]

it should work, but now I cannot see the bullets;

here is the code after today's class (i am trying to fixc the bullets before I try to fix the enemies)

code:

var win, win2 : int var message : string var keyup : real var count : real var chars : array char of boolean var x1, x2, y1, y2, xb1, yb1 : int var x3, x4, y3, y4 : int var clr : int var shot : int var mx, my, button : int var boomy1, boomx1, boomy2, boomx2 : int var continue : string var random, random1 : int var level : string var scnt, acnt : int win := Window.Open ("position:middle,center, graphics: 500;640, Title: Space shooter v.1") View.Set ("offscreenonly") x1 := 320 y1 := 20 x2 := 20 y2 := 20 clr := 2 boomx1 := 1 boomy1 := 1 process bullet %need to take a snapshot of the x/y cordinates of the mouse and fire a bullet straight up without (so mouse wont move bullet) ALSO NEEDS TO STOP FLASHING (viewupdate)     xb1 := mx     yb1 := my     for a : 1 .. 660         drawfilloval (xb1, yb1 + a, 10, 10, yellow)         delay (1)         drawfilloval (yb1, yb1 + a, 10, 10, 0)     end for end bullet %process randships %random1 := Rand.Int (0,50) %if random1 > 25 then %    random := Rand.Int (0, 500) %    Draw.FillOval (random, 500, 10, 10, purple) %    for a : 1 .. 801 %        drawfilloval (random, 500 - a, 10, 10, green) %        delay (1) %        drawfilloval (random, 500 - a, 10, 10, 0) %    end for %end if %end randships put "Welcome to Paul's Space shooter" put " " put " Mouse Rclick = shoot" put " Mouse = movment" put " " put "type y to play, n to quit" View.Update get continue if continue = "n"         then     Window.Close (win) end if scnt := 0 loop     loop         scnt := scnt + 1         if scnt = 10 then     if button = 1 then                 fork bullet                 View.Update             end if         end if         scnt := 0         exit     end loop     level := "y"     if continue = "n"             then         exit     end if     mousewhere (mx, my, button)     Draw.FillOval (mx, my, x2, y2, 1)     if my >= 640             then         my := 640     end if     if mx >= 500             then         mx := 500     end if     if mx <= 0             then         mx := 0     end if     if my <= 0             then         my := 0     end if     View.Update     cls     Draw.FillOval (mx, my, x2, y2, 1)     %    if button = 1 then     %        fork bullet     %    end if     %    if level = "y" then     %        fork randships     %    end if end loop win2 := Window.Open ("position:middle,center, graphics: 200;10, Title: bye!") put "thx for playing!" delay (1000) Window.Close (win2)

[vapour99]

I have implemented the correct array code; thanks for the recommendation TheWanderer