8. Classes

Classes

--# Main
-- class

-- Use this function to perform your initial setup
function setup()
    b={}
    for i=1,5 do
        b[i]=Ball()
    end
    r={}
    for i=1,5 do
        r[i]=Rect()
    end    
    CreateWalls()
end

-- This function gets called once every frame
function draw()
    background(195, 195, 201, 255)
    for i=1,#b do
        b[i]:draw()
    end
    for i=1,#r do
        r[i]:draw()
   end
end

function CreateWalls()
    leftWall = CreateWall(1,1,1,HEIGHT-1,1.0) 
    rightWall = CreateWall(WIDTH-1,0,WIDTH-1,HEIGHT-1,0.9) 
    bottomWall = CreateWall(1,1,WIDTH-1,1,0.2) 
    topWall = CreateWall(1,HEIGHT-1,WIDTH-1,HEIGHT-1,0.7)
end

--this function creates one wall (actually just a line)
function CreateWall(x,y,x1,y1,r)
    local w = physics.body(EDGE,vec2(x,y),vec2(x1,y1)) -- vec2
    w.restitution=r --see comment above
    return w
end

--# Ball
Ball = class()

function Ball:init(x,y,d,c)
    self.x=x or math.random(0,WIDTH)
    self.y=y or math.random(0,HEIGHT)
    self.diameter=d or math.random(50,200)
    self.colr=c or color(math.random(0,255),math.random(0,255),math.random(0,255))
    self.p=Physics(CIRCLE,{self.diameter/2},self.x,self.y) --physics uses radius
end

function Ball:draw()
    pushStyle() -- store style settings
    fill(self.colr) --set color
    pushMatrix()
    local x,y,a=self.p:currentPosition()
    translate(x,y)
    rotate(a)
    ellipse(0,0,self.diameter)
    popMatrix()
    popStyle() -- put back style settings
end



--# Rect
Rect = class()

function Rect:init(x,y,w,h,c)
    self.x=x or math.random(0,WIDTH)
    self.y=y or math.random(0,HEIGHT)
    self.width=w or math.random(60,150)
    self.height=h or math.random(30,100)
    self.colr=c or color(math.random(0,255),math.random(0,255),math.random(0,255))
    local data={}
    table.insert(data,vec2(-self.width/2,-self.height/2))
    table.insert(data,vec2(-self.width/2,self.height/2))
    table.insert(data,vec2(self.width/2,self.height/2))
    table.insert(data,vec2(self.width/2,-self.height/2))
    self.p=Physics(POLYGON,data,self.x,self.y)
end

function Rect:draw()
    pushStyle() -- store style settings
    fill(self.colr) --set color
    pushMatrix()
    local x,y,a=self.p:currentPosition()
    translate(x,y)
    rotate(a)
    rect(-self.width/2,-self.height/2,self.width,self.height)
    popMatrix()
    popStyle() -- put back style settings
end



--# Physics
Physics = class()

--type=CIRCLE or POLYGON
--data is a table. For circles it is one value, the radius, while for a polygon it is a set of vec2
--x,y is the initial position of the centre
--a is the initial angle
--g is the gravity value, 0=tabletop, 1=normal (things fall down)
--r is the restitution, ie springiness
--f is friction
--lv is linear velocity
--i is any info you want to store to identify this object, eg a name
function Physics:init(type,data,x,y,a,g,r,f,lv,i)  
    if type==CIRCLE then
        self.body=physics.body(CIRCLE,data[1]) 
    elseif type==POLYGON then
        self.body=physics.body(POLYGON,unpack(data))
    end
    self.body.x=x
    self.body.y=y
    self.body.angle=a or 0
    if g then self.body.gravityScale=1 else self.body.gravityScale=0 end
    self.body.restitution=r or 1
    self.body.friction=f or 0.1
    if lv==nil then lv=vec2(100+math.random(400),100+math.random(400)) end
    self.body.linearVelocity=lv
    self.body.info=i
end

function Physics:currentPosition()
    return self.body.x, self.body.y,self.body.angle
end