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TheXploder

Mon Jan 19, 2004 11:06 pm


Moving Ball, Flicker Reduction

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There are many ways to update the position of a ball one of which is
'cls' which stands for 'clear screen' I'll give you a simple tutorial on how to reduce that flicker.

The code using cls:


var x : int := 0 % creates a new variable of integer type and sets the
                       % value to 0

proc objBall (x, y, ballSize, clr : int) % starts a procedure with the
% variable name 'objBall' and containing 'x, y, ballsize, clr' variables, 
% which  are considered to be local variables

drawfilloval (x + ballSize, y + ballSize, ballSize, ballSize, clr) 
% draws an oval

end objBall 
% ends the 'objBall' procedure

loop
    objBall (x, 0, 10, 1) % "objBall's" variables that are contained can be 
% called and given a value by using subscripts

    delay (10)

    x += 1 % increases x value by one each loop cycle

    cls %clears the screen
end loop

%%%%And now using a better technigue:%%%%

var x : int := 0

proc objBall (x, y, ballSize, clr : int)
      drawfilloval (x + ballSize, y + ballSize, ballSize, ballSize, clr) 
end objBall 

loop

    objBall (x, 0, 10, 1)
% The colour of the ball here is represented by the last number...

    delay (10)

    x += 1

% Instead of using cls this time I'll just change the colour of the ball to 0 
% or white

    objBall (x, 0, 10, 0)

end loop


As you can see this reduces the fickering to a minimum. Because the screen is not redrawn completely, only were the ball previously was.

Hope this tutorial helps..  :P
-=TheXploder=-


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Tony

Mon Jan 19, 2004 11:27 pm



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or you could just use View.Update (or now that 4.0.5 is out, View.UpdateArea) :lol:

good job for trying though+Bits


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Skizzarz

Tue Jan 20, 2004 6:54 pm



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thx for the great tutorial, i used some of the code in my "hockey puck" program for school and all my classmates wonder how its so smooth :lol:


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Mazer

Tue Jan 20, 2004 7:51 pm


Re: Moving Ball, Flicker Reduction

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    objBall (x, 0, 10, 1)
% The colour of the ball here is represented by the last number...
    delay (10)
    x += 1
% Instead of using cls this time I'll just change the colour of the ball to 0 
% or white
    objBall (x, 0, 10, 0)


You should have blanked out the ball before increasing the x coordinate, otherwise you get this blue streak.

    objBall (x, 0, 10, 1)
% The colour of the ball here is represented by the last number...
    delay (10)

% Instead of using cls this time I'll just change the colour of the ball to 0 
% or white
    objBall (x, 0, 10, 0)
    x += 1



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LiquidDragon

Wed Feb 18, 2004 8:16 pm



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well couldnt your just do something like this?


View.Set ("offscreenonly")

var x : int := 0 

proc objBall (x, y, ballSize, clr : int) 
      drawfilloval (x + ballSize, y + ballSize, ballSize, ballSize, clr) 
end objBall 

loop 

    objBall (x, 0, 10, 1) 
        View.Update
% The colour of the ball here is represented by the last number... 
    delay (10) 

% Instead of using cls this time I'll just change the colour of the ball to 0 
% or white 
    objBall (x, 0, 10, 0) 
    x += 1 

end loop 



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Kamikagushi

Thu Jun 10, 2004 4:34 pm



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~a question~after you use View.Update~how would you turn it off~


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Delos

Thu Jun 10, 2004 5:18 pm



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Repost your question in the Help forum, you'll get better answers...


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nerdie

Mon Jun 21, 2004 3:06 pm



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does View.Set ("nooffscreenonly") exist?
and if it does did i spell it correctly?


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GlobeTrotter

Mon Jun 21, 2004 3:37 pm



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It does exist, you spelled it right.


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naoki

Fri Jun 25, 2004 4:36 pm



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View.Update is merely a one time thing, like cls. It acts by basically showing you anything drawn on the screen before View.Update was called.

Thus, you may need to call View.Update in several places of your program in order to see different things.

As well, isn't Turing set by default to nooffscreenonly? So why bother unless you set to offscreen in the first place