Cut the fruit

gistfile1.txt

    
function setup()
    ReadImages()
    tp={} --this will store our swipe points so we can draw a line 
    fruit={} --the items we will cut
    AddFruit() --add the first fruit
    FPS=60 --speed checker
end

--read in all the images we will use
function ReadImages()
    images={readImage("SpaceCute:Health Heart"),readImage("Tyrian Remastered:Space Ice 5"),
        readImage("Small World:House White"),readImage("Small World:Store Extra Large"),
        readImage("Planet Cute:Gem Orange"),readImage("Planet Cute:Gem Blue"),readImage("Planet Cute:Enemy Bug")}
end

--drops a new piece of fruit
function AddFruit()
    local i=math.random(1,#images)
    local img=images[i]
    local w,h=img.width,img.height
    local pos=vec2((0.2+0.6*math.random())*WIDTH,HEIGHT+100)
    --create a rectangle mesh for the image
    local m=mesh()
    m.vertices={vec2(-w/2,-h/2),vec2(w/2,-h/2),vec2(w/2,h/2),vec2(w/2,h/2),vec2(-w/2,h/2),vec2(-w/2,-h/2)}
    m.texCoords={vec2(0,0),vec2(1,0),vec2(1,1),vec2(1,1),vec2(0,1),vec2(0,0)}
    m.texture=img
    m:setColors(color(255))
    --add to our objects table
    --replace tells Codea if the object is replaced when it goes off the screen
    --it is true except where objects have been split, when only one of the two new objects
    --has this set to true
    table.insert(fruit,{m=m,pos=pos,w=w,h=h,img=img,angle=0,rot=1,speed=vec2(0,-2),replace=true})
end
    
function draw()
    background(123, 186, 210, 255)
    --add a new fruit every three seconds until we have 5 in total
    if #fruit<5 and ElapsedTime/7>#fruit then AddFruit() end
    FPS=FPS*0.9+0.1/DeltaTime --speed check
    text(math.floor(FPS),50,50)
    --update and draw the objects
    for i,f in pairs(fruit) do
        f.angle=f.angle+f.rot --rotation
        f.pos=f.pos+f.speed  --position
        if f.pos.y<-50 then --it's fallen off the screen
            if f.replace then AddFruit() end --replace it if necessary
            table.remove(fruit,i) --delete it
        else --draw it
            pushMatrix()
            translate(f.pos.x,f.pos.y)
            rotate(f.angle)
            f.m:draw()
            popMatrix()  
        end    
    end  
    -- draw the swipe line, if there is one 
    stroke(255,255,0)
    strokeWidth(4)
    for j=1,#tp-1 do line(tp[j].x,tp[j].y,tp[j+1].x,tp[j+1].y) end
end

function touched(t)
    if t.state==BEGAN then 
        tp={vec2(t.x,t.y)} --first swipe point
        for i,f in pairs(fruit) do --clear enter,exit values for all objects
            f.enter,f.exit=nil,nil
        end
    elseif t.state==MOVING then 
        local v=vec2(t.x,t.y)
        table.insert(tp,v) --add point to swipe list
        for i,f in pairs(fruit) do
            local tv=Transform(f,v) --rotate point
            if IsInsideFruit(f,tv) then --if inside, set enter or exit point
                f.enter = f.enter or tv
            elseif f.enter and not f.exit then --we've exited, split the object
                f.exit=tv
                BreakFruit(i)
            end
        end
    elseif t.state==ENDED then 
        tp={}
    end
end

function IsInsideFruit(f,p)
    if f.broken then return end --we can't swipe on split objects, so they have a "broken" property = true
    --this prevents them ever returning true for this function, ie they get ignored
    if math.abs(p.x-f.pos.x)<f.w/2 and math.abs(p.y-f.pos.y)<f.h/2 then return true end
end

--rotates a point by the negative of the object's angle
function Transform(f,p)
    local r=math.rad(-f.angle)
    local s,c=math.sin(r),math.cos(r)
    local pp=p-f.pos --rotate around the object's centre
    return vec2(pp.x*c-pp.y*s,pp.x*s+pp.y*c)+f.pos
end

--used below
function Angle(v)
    return math.atan2(v.y,v.x)
end

function BreakFruit(id)
    local f=fruit[id]
    local p1,p2=f.enter,f.exit
    local w,h,w2,h2=f.w,f.h,f.w/2,f.h/2
    local c={vec2(-w2,-h2),vec2(w2,-h2),vec2(w2,h2),vec2(-w2,h2)} --corners of image
    local p,pp1,pp2=(p1+p2)/2-f.pos,p1-f.pos,p2-f.pos --localised midpoint and ends of cut line
    local a1=Angle(pp1-p) --angle of line from p to pp1
    local a2=Angle(pp2-p) --angle of line from p to pp2
    local v1,v2={{pp1,a1},{pp2,a2}},{{pp1,a1},{pp2,a2}} --add cut points to both tables
    if a1>a2 then a1,a2=a2,a1 end --swap them if a2>a1
    for i=1,#c do 
        local a=Angle(c[i]-p) --angle of line from p to c[i]
        --if angle is between a1 and a2, add point to first list, else second list
        if a>a1 and a<a2 then v1[#v1+1]={c[i],a} else v2[#v2+1]={c[i],a} end
    end
    --sort both tables by angle
    table.sort(v1,function(a,b) return a[2]<b[2] end)
    table.sort(v2,function(a,b) return a[2]<b[2] end)
    --create two meshes
    local m1,m2=mesh(),mesh()
    local j
    local v,t={},{}
    --create triangles
    for i=1,#v1 do
        v[#v+1]=v1[i][1]  
        v[#v+1]=p
        j=i+1 if j>#v1 then j=1 end
        v[#v+1]=v1[j][1]
    end
    m1.vertices=v
    local u=vec2(0,0)
    --create texture mappings
    for i=1,#v do 
        t[i]=vec2((v[i].x+w2)/w,(v[i].y+h2)/h)
        t[i].x=math.max(0,math.min(1,t[i].x)) 
        t[i].y=math.max(0,math.min(1,t[i].y)) 
        u=u+v[i]
    end
    --calculate average of vertex positions, this will be the position of this object
    local pos=f.pos+u/#v
    m1.texCoords=t
    m1.texture=f.img
    m1:setColors(color(255))
    table.insert(fruit,{m=m1,pos=pos,img=img,angle=f.angle,rot=f.rot,speed=vec2(-1,-3),broken=true,replace=true})
    
    --now do it all again for the second object
    local v,t={},{}
    for i=1,#v2 do
        v[#v+1]=v2[i][1]
        v[#v+1]=p
        j=i+1 if j>#v2 then j=1 end
        v[#v+1]=v2[j][1]
    end
    m2.vertices=v
    local u=vec2(0,0)
    for i=1,#v do 
        t[i]=vec2((v[i].x+w2)/w,(v[i].y+h2)/h) 
        t[i].x=math.max(0,math.min(1,t[i].x)) 
        t[i].y=math.max(0,math.min(1,t[i].y)) 
        u=u+v[i]
    end
    local pos=f.pos+u/#v
    m2.texCoords=t
    m2.texture=f.img
    m2:setColors(color(255))
    table.insert(fruit,{m=m2,pos=pos,img=img,angle=f.angle,rot=-f.rot,speed=vec2(1,-3),broken=true})
    --delete the old object
    table.remove(fruit,id)
end