zoom

gistfile1.txt

-- Main

function setup()
    numtouches=0 --number of current touches
    aim={id=0,x=0,y=0} --details for touch which is aiming
    createScope() 
    CreateBackground()
    shots={} --table for shots fired
    shotSize=7 --size of shot mark
    parameter.integer("Zoom",1,5,2)
    shotColour=color(255)
    print("Hold and move one finger on the screen to aim")
    print("Tap with a second finger to shoot")
end

function CreateBackground()
    backdrop=image(WIDTH,HEIGHT)
    setContext(backdrop)
        img=readImage("Small World:Church")
        sprite(img,400,300)
        img=readImage("Small World:House White")
        sprite(img,250,550)
        img=readImage("Small World:Mine Large")
        sprite(img,300,150)
        img=readImage("Small World:Windmill")
        sprite(img,600,400)
    setContext()
end

function createScope()
    scopeBuffer=90 --draw scope this many pixels above finger (so user can see scope!)
    scopeOuterRing=120 --pixels
    scopeInnerRing=60
    crossHairExtends=20 --crosshairs extend this far outside rings
    local s=scopeOuterRing+crossHairExtends*2 --total width
    --since we're drawing the same scope a lot, we create an image
    imgScope=image(s,s)
    setContext(imgScope) --start drawing on the image instead of the screen
        ellipseMode(CENTER) 
        strokeWidth(.5)  --lines one pixel wide
        stroke(94, 89, 89, 255) --dark colour
        fill(0,0,0,0) --transparent fill (the last item, alpha, is nil)
        ellipse(s/2,s/2,scopeOuterRing)  --draw rings
        ellipse(s/2,s/2,scopeInnerRing)
        line(s/2,0,s/2,s) --draw crosshairs
        line(0,s/2,s,s/2)
    setContext() --stop drawing on image
end

function touched(touch)
    if touch.state==BEGAN then --user has just touched, hasn't let go yet
        numtouches=numtouches+1 --keep count
        if numtouches==1 then  --if first touch, it is aiming, store details
            aim.id=touch.id --so we know which touch is which when we shoot
            aim.x=touch.x
            aim.y=touch.y
        end
    elseif touch.state==MOVING then --finger is moving
        if touch.id==aim.id then --if the aiming finger, store new x,y
            aim.x=touch.x
            aim.y=touch.y
        end
    elseif touch.state==ENDED then 
        if touch.id==aim.id then aim.id=0 --if aiming finger lifted, remove scope
        elseif numtouches>1 then --if more than one finger, bang bang!
            shots[#shots+1]={x=aim.x,y=aim.y+scopeBuffer} --add shot to table
        end
        numtouches=numtouches-1 --adjust touch count  
    end
end

function draw()
    background(195, 211, 215, 255)
    pushStyle()
    --make copy of background
    imgBack=backdrop:copy(0,0,backdrop.width,backdrop.height)
    setContext(imgBack)
    --draw past shots on screen
    for i,v in pairs(shots) do
        fill(shotColour)
        strokeWidth(0)
        ellipse(v.x,v.y,shotSize)
    end
    
    if aim.id>0 then --if aiming, draw scope and zoom
        local x,y=aim.x, aim.y+scopeBuffer --aiming point
        --zoom first
        --create new image to contain zoomed image and scope
        img=image(imgScope.width,imgScope.height)
        s=imgScope.width
        setContext(img)
        spriteMode(CORNER)
        --draw backdrop on our little image so it shows the bit we want
        --note zoom factor
        sprite(imgBack,-x*Zoom+s/2,-y*Zoom+s/2,Zoom*backdrop.width)
        --overlay the scope
        sprite(imgScope,0,0)
        setContext() --this is needed for some reason before we set it to a different image
        setContext(imgBack) --now draw our zoom image onto the background copy
        spriteMode(CENTER)
        sprite(img,x,y)
    end
    setContext()
    spriteMode(CORNER)
    sprite(imgBack,0,0)  --draw the background copy with everything on it
    popStyle()  
end