Breakout game - GameCreators Forum

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Framester

11

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Joined: 8th Jan 2013

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Posted: 26th Feb 2013 17:39

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I've coded most of my breakout game right now, but currently have a issue with the angles. Right now i'm just using 8 directions

+ Code Snippet

MoveBall:

   if direction = 9
      direction = 1
   endif

   if direction = 1
      ballx = ballx + 3
      bally = bally - 6
   endif

    if direction = 2
       ballx = ballx + 3
       bally = bally + 6
    endif

   if direction = 3
      ballx = ballx - 3
      bally = bally - 6
   endif

   if direction = 4
      ballx = ballx - 3
      bally = bally + 6
   endif

   if direction = 5
      ballx = ballx + 2
      bally = bally - 6
   endif

   if direction = 6
      ballx = ballx + 2
      bally = bally + 6
   endif

   if direction = 7
      ballx = ballx - 2
      bally = bally - 6
   endif

   if direction = 8
      ballx = ballx - 2
      bally = bally + 6
   endif

return

I'm using a direction + 1 to alter when it hits the walls and brick. Im thinking of having angles so when the ball hits 1 half of the paddle, it will go one way, or vice versa. Any ideas where I could start with this please.

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Libervurto

17

Years of Service

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Joined: 30th Jun 2006

Location: On Toast

Posted: 26th Feb 2013 18:25 Edited at: 26th Feb 2013 18:28

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Look into using sine and cosine:

+ Code Snippet

sync on
sync rate 100

xmin = 100
xmax = 600
ymin = 100
ymax = 400
speed = 3

ballx = (xmax+xmin)/2
bally = (ymax+ymin)/2
balla# = 45

do
	gosub moveball
	
	ink 128,0
	box xmin,ymin,xmax,ymax
	ink -2,0
	box ballx-10,bally-10,ballx+10,bally+10
	sync:cls
loop


MoveBall:
	inc ballx, sin(balla#)*speed
	inc bally, cos(balla#)*speed
	if ballx < xmin or ballx > xmax or bally < ymin or bally > ymax
		balla# = balla#+90
	endif
return

This is a bodged example that will not work for all angles. Read this for useful maths: http://en.wikipedia.org/wiki/Reflection_(physics)

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Phaelax

DBPro Master

21

Years of Service

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Joined: 16th Apr 2003

Location: Metropia

Posted: 26th Feb 2013 18:48

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When the ball hits the paddle, determine the angle of reflection:

(paddle.x is the center of the paddle in this case)
n# = (ball.x - paddle.x) / (paddle.length/2)

That will return a float from -1 to +1.
If 180 degrees points straight up from the paddle:

angle = 180 + 65*n#

This will give us an angle from 115 to 245. Now store this direction as a vector

ball.vx = sin(angle)
ball.vy = cos(angle)

Move your ball like so:
ball.x = ball.x + ball.vx*ball.speed
ball.y = ball.y + ball.vy*ball.speed

Then, if you hit a side wall or the side of a brick, invert the X direction:

if ball hits side of something then ball.vx = -ball.vx

And do the same thing for ball.vy if you hit the top or bottom of something.

"You're all wrong. You're all idiots." ~Fluffy Rabbit

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