The Flickering Mystery

[ziggy2shoes]

Hello!

Note: I am an inexperienced programmer.

Thank you for taking the time to read this post good sir/ma'am.
I am making a game for school. (Aren't we all?)

Everything was going fine until somewhere during the throes of coding I seem to have done something to cause the avatar (a .bmp of a zoid) in the game to flicker oddly.

Now, not wanting to trouble for help immediately I looked for a case such as mine. I soon discovered an apparantly useful command called View.Update!

Great, however, I am not sure where to put this command to stop the flickering, I have tried many positions but to no avail. Alas, I turn to you great heroes of compsci.ca in hope that you might be able to help me, as time permits naturally.

Thank you once again and enjoy the rest of your exsistence.

Yours enigmatically,
Pepito, Supreme Commander of the 18th Homing Pigeon Surveillance Unit

THE CODE:

Quote:

%***********************************
%* *
%* Z O I D S : N E M E S I S *
%* *
%***********************************

%[ Our greatest enemy is often, ]
%[ ourselves. ]

/*
Purpose: An entertaining game based around the fictional world of ZOIDS,
a popular line of toys in Japan as well as an animated series.
The game is a 2D battle game in which one player fights another play with
a ZOID. If you are unfamiliar with ZOIDS and the ZOIDS universe I suggest
you search it @ www.wikipedia.org. Thank you.
*/

/*
Created by Joshua Williams (c) 2006
Thank you www.compsci.ca for all your
helpful tutorials and info..........
*/
%*******************************
%* *
%* SCREEN SETTINGS *
%* *
%*******************************

% graphic setting and background
setscreen ("graphics:max;max,nocursor,title:-= Z O I D S : N E M E S I S =-")

%*******************************
%* *
%* MENU / INTERFACE *
%* *
%*******************************

% font variables
var font1 : int
var font2 : int
var font3 : int
var font4 : int
var font5 : int

% black background
colorback (black)
cls

% ZiggyGames title screen
font2 := Font.New ("arial:36")
Font.Draw ("ZiggyGames", 350, 325, font2, brightred)
delay (500)
cls

% Enigmatically Presents... title screen
delay (500)
font1 := Font.New ("arial:36")
Font.Draw ("Enigmatically Presents...", 250, 325, font1, brightred)
delay (500)
cls
delay (500)

% title logo variables
var title1 := Pic.FileNew ("logo1.bmp")
var title2 := Pic.FileNew ("logo2.bmp")
var title3 := Pic.FileNew ("logo3.bmp")
var title4 := Pic.FileNew ("logo4.bmp")

% title logo 1
colorback (black)
cls
delay (1000)
for pan1 : -400..375
Pic.Draw (title1, pan1, 250, picMerge)
delay (1)
end for

% title logo 2
for decreasing pan2 : 1000..375
Pic.Draw (title2, pan2, 250, picMerge)
delay (1)
end for

% title logo 3
for pan3 : -400..250
Pic.Draw (title3, 375, pan3, picMerge)
delay (1)
end for

% title logo 4
for decreasing pan4 : 700..250
Pic.Draw (title4, 375, pan4, picMerge)
delay (1)
end for

% top title box line
for bar1 : 350..675
drawline (bar1, 420, bar1, 420, brightred)
delay (5)
end for

% right title box line
for decreasing bar2 : 420..230
drawline (675, bar2, 675, bar2, brightred)
delay (5)
end for

% bottom title box line
for decreasing bar3 : 675..350
drawline (bar3, 230, bar3, 230, brightred)
delay (5)
end for

% left title box line
for bar4 : 230..420
drawline (350, bar4, 350, bar4, brightred)
delay (5)
end for
delay (5000)
cls

% loading screen
font4 := Font.New ("arial:16")
Font.Draw ("Loading...", 460, 450, font4, yellow)
drawbox (359, 399, 651, 426, yellow)
for horz : 360 .. 650
drawfillbox (horz, 400, horz, 425, brightred)
delay (10)
end for
delay (500)
cls
% menu
color (white)
% button text
locatexy (500, 350)
put "PLAY"
locatexy (300, 200)
put "HELP"
locatexy (700, 200)
put "EXIT"
drawbox (maxx - 75, maxy - 75, 0 + 75, 0 + 75, brightred)
drawbox (maxx - 125, maxy - 125, 0 + 125, 0 + 125, brightred)
drawfill (maxx - 110, maxy - 110, red, brightred)
% play button box
drawbox (480, 340, 545, 370, brightred)
% help button box
drawbox (280, 180, 345, 220, yellow)
% exit button box
drawbox (680, 180, 745, 220, yellow)
% menu title
var titlefont := Font.New ("system:44")
Font.Draw ("Z O I D S : N E M E S I S", 200, maxy - 200, titlefont, yellow)


delay (1000)
cls

%*******************************
%* *
%* GAMEPLAY *
%* *
%*******************************

% liger variables
var rght := Pic.FileNew ("ligerleft.bmp")
var lft := Pic.FileNew ("ligerright.bmp")

var x, y, spd, check : int
% var for input.keydown (key)
var key : array char of boolean
%sets variables x and y
x := 10
y := 50
% boolean movement variables
var right : boolean := false
var left : boolean := false


%zoid
procedure draw
% zoid left and right movement pics

Pic.Draw (rght, x, y - 40, 2)

% if's for pic.draw
if right = true then
Pic.Draw (rght, x, y - 40, 2)
end if
if left = true then
Pic.Draw (lft, x, y - 40, 2)
end if

%bottom of screen line
drawfillbox (0, 0, maxx, 18, grey)

end draw
%draw procedure (zoid + bottom line)
draw
View.Update
%var check = how high the zoid can go (0)
check := 0
%var spd = gravity force (0)
spd := 0
loop
View.Update

%sets key as var for key pressed
Input.KeyDown (key)

%check is preset to 0
if check = 0 then

%if w is pressed (Input.KeyDown), spd = 32 and check = 0
if key (' ') then

%var spd = 32
spd := 32

%var check = 0
check := 0

end if

end if

%Moves Horizontally

%d is pressed
if key ('d') then
left := true
right := false

%moves figure 5 to the right
x := x + 5

%a is pressed
elsif key ('a') then
right := true
left := false

%moves figure 5 to the left
x := x - 5

end if

%height of jump
%once y= more then 51 check = 1
if y >= 51 then

check := 1

% if y = 50 then check = 0
elsif y = 50 then

check := 0

end if

%controls the rate of fall (gravity)
%divides spd by 2 if greater than 0
if spd > 0 then
spd := spd div 2

elsif spd < 0 then


spd := spd * 2
end if

% if spd = 1 then it is = to -1
if spd = 1 then
spd := -1
end if

% adds gravity to var y
y := y + spd

%sets gravity (spd) to 0 when y = less than 50.
%if y is more than 50, then y always increases (keeping the figure afloat)
if y <= 50 then
spd := 0
y := 50
end if




%delay
delay (50)

%clear screen
cls

%procedure draw
draw


end loop

If necessary I can attach to you a .zip of the whole schidoodle, pictures and all.

[richcash]

In order to use View.Update you need to use this :

code:

View.Set ("offscreenonly")

View.Set is the same command as setscreen, so you could just add the "offscreenonly" part into your existing setscreen statement.

[DemonZ]

yes u must use the offscreenonly when using View.Set or setscreen, but that will only make a blank page, because everything that was drawn to the screen was copied off the screen and is waiting to paste what was drawn. This is known as animation buffering, so when you call the setscreen or View.Set and are using offscreenonly, make sure you add a View.Update or View.UpdateArea in your main loop followed by a cls to stop all the flickering, like so:

code:

%variables, procedures, processes, whatever on top setscreen ("offscreenonly") % Main loop loop % All the game logic View.Update cls end loop

This way it will copy what was drawn to the screen and buffer the animation, making it not flicker.
Hope this helps

[ziggy2shoes]

Excellent show chaps, it worked!
Thank you very much.
I'd give you some bits but alas, I don't have many.
Oh well. Thank you!