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class Peg
def initialize(x, y, block_size)
@x = x # x cordinate of the LEFT side of the peg
@y = y # y cordinate of the RIGHT side of the peg
@block_size = block_size # diameter of the peg
@radius = @block_size/2.0 # radius of the peg
@center = { # cordinatees of the CENTER of the peg
x: @x+@block_size/2.0,
y: @y+@block_size/2.0
}
@r = 255 # color of the peg
@g = 0
@b = 0
@velocity = {x: 2, y: 0}
end
def draw args
args.outputs.sprites << [ # draw the peg according to the @x, @y, @radius, and the RGB
@x,
@y,
@radius*2.0,
@radius*2.0,
"sprites/circle-white.png",
0,
255,
@r, #r
@g, #g
@b #b
]
end
def calc args
if collisionWithBounce? args # if the is a collision with the bouncing ball
collide args
@r = 0
@b = 0
@g = 255
else
end
end
# do two circles (the ball and this peg) intersect
def collisionWithBounce? args
squareDistance = ( # the squared distance between the ball's center and this peg's center
(args.state.ball.center.x - @center.x) ** 2.0 +
(args.state.ball.center.y - @center.y) ** 2.0
)
radiusSum = ( # the sum of the radius squared of the this peg and the ball
(args.state.ball.radius + @radius) ** 2.0
)
# if the squareDistance is less or equal to radiusSum, then there is a radial intersection between the ball and this peg
return (squareDistance <= radiusSum)
end
# ! The following links explain the getRepelMagnitude function !
# https://raw.githubusercontent.com/DragonRuby/dragonruby-game-toolkit-physics/master/docs/docImages/LinearCollider_4.png
# https://raw.githubusercontent.com/DragonRuby/dragonruby-game-toolkit-physics/master/docs/docImages/LinearCollider_5.png
# https://github.com/DragonRuby/dragonruby-game-toolkit-physics/blob/master/docs/LinearCollider.md
def getRepelMagnitude (args, fbx, fby, vrx, vry, ballMag)
a = fbx ; b = vrx ; c = fby
d = vry ; e = ballMag
if b**2 + d**2 == 0
#unexpected
end
x1 = (-a*b+-c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 + d**2 - a**2 * d**2)**0.5)/(b**2 + d**2)
x2 = -((a*b + c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 * d**2 - a**2 * d**2)**0.5)/(b**2 + d**2))
err = 0.00001
o = ((fbx + x1*vrx)**2 + (fby + x1*vry)**2 ) ** 0.5
p = ((fbx + x2*vrx)**2 + (fby + x2*vry)**2 ) ** 0.5
r = 0
if (ballMag >= o-err and ballMag <= o+err)
r = x1
elsif (ballMag >= p-err and ballMag <= p+err)
r = x2
else
#unexpected
end
if (args.state.ball.center.x > @center.x)
return x2*-1
end
return x2
#return r
end
#this sets the new velocity of the ball once it has collided with this peg
def collide args
normalOfRCCollision = [ #this is the normal of the collision in COMPONENT FORM
{x: @center.x, y: @center.y}, #see https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.mathscard.co.uk%2Fonline%2Fcircle-coordinate-geometry%2F&psig=AOvVaw2GcD-e2-nJR_IUKpw3hO98&ust=1605731315521000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCMjBo7e1iu0CFQAAAAAdAAAAABAD
{x: args.state.ball.center.x, y: args.state.ball.center.y},
]
normalSlope = ( #normalSlope is the slope of normalOfRCCollision
(normalOfRCCollision[1].y - normalOfRCCollision[0].y) /
(normalOfRCCollision[1].x - normalOfRCCollision[0].x)
)
slope = normalSlope**-1.0 * -1 # slope is the slope of the tangent
# args.state.display_value = slope
pointA = { # pointA and pointB are using the var slope to tangent in COMPONENT FORM
x: args.state.ball.center.x-1,
y: -(slope-args.state.ball.center.y)
}
pointB = {
x: args.state.ball.center.x+1,
y: slope+args.state.ball.center.y
}
perpVect = {x: pointB.x - pointA.x, y:pointB.y - pointA.y} # perpVect is to be VECTOR of the perpendicular tangent
mag = (perpVect.x**2 + perpVect.y**2)**0.5 # find the magniude of the perpVect
perpVect = {x: perpVect.x/(mag), y: perpVect.y/(mag)} # divide the perpVect by the magniude to make it a unit vector
perpVect = {x: -perpVect.y, y: perpVect.x} # swap the x and y and multiply by -1 to make the vector perpendicular
args.state.display_value = perpVect
if perpVect.y > 0 #ensure perpVect points upward
perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
end
previousPosition = { # calculate an ESTIMATE of the previousPosition of the ball
x:args.state.ball.center.x-args.state.ball.velocity.x,
y:args.state.ball.center.y-args.state.ball.velocity.y
}
yInterc = pointA.y + -slope*pointA.x
if slope == INFINITY # the perpVect presently either points in the correct dirrection or it is 180 degrees off we need to correct this
if previousPosition.x < pointA.x
perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
yInterc = -INFINITY
end
elsif previousPosition.y < slope*previousPosition.x + yInterc # check if ball is bellow or above the collider to determine if perpVect is - or +
perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
end
velocityMag = # the current velocity magnitude of the ball
(args.state.ball.velocity.x**2 + args.state.ball.velocity.y**2)**0.5
theta_ball=
Math.atan2(args.state.ball.velocity.y,args.state.ball.velocity.x) #the angle of the ball's velocity
theta_repel=
Math.atan2(args.state.ball.center.y,args.state.ball.center.x) #the angle of the repelling force(perpVect)
fbx = velocityMag * Math.cos(theta_ball) #the x component of the ball's velocity
fby = velocityMag * Math.sin(theta_ball) #the y component of the ball's velocity
repelMag = getRepelMagnitude( # the magniude of the collision vector
args,
fbx,
fby,
perpVect.x,
perpVect.y,
(args.state.ball.velocity.x**2 + args.state.ball.velocity.y**2)**0.5
)
frx = repelMag* Math.cos(theta_repel) #the x component of the repel's velocity | magnitude is set to twice of fbx
fry = repelMag* Math.sin(theta_repel) #the y component of the repel's velocity | magnitude is set to twice of fby
fsumx = fbx+frx # sum of x forces
fsumy = fby+fry # sum of y forces
fr = velocityMag # fr is the resulting magnitude
thetaNew = Math.atan2(fsumy, fsumx) # thetaNew is the resulting angle
xnew = fr*Math.cos(thetaNew) # resulting x velocity
ynew = fr*Math.sin(thetaNew) # resulting y velocity
if (args.state.ball.center.x >= @center.x) # this is necessary for the ball colliding on the right side of the peg
xnew=xnew.abs
end
args.state.ball.velocity.x = xnew # set the x-velocity to the new velocity
if args.state.ball.center.y > @center.y # if the ball is above the middle of the peg we need to temporarily ignore some of the gravity
args.state.ball.velocity.y = ynew + GRAVITY * 0.01
else
args.state.ball.velocity.y = ynew - GRAVITY * 0.01 # if the ball is bellow the middle of the peg we need to temporarily increase the power of the gravity
end
args.state.ball.center.x+= args.state.ball.velocity.x # update the position of the ball so it never looks like the ball is intersecting the circle
args.state.ball.center.y+= args.state.ball.velocity.y
end
end
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