Wheel spinning with physics

[kkaaoss]

Hi Everybody,

I’m a Beginner with Corona sdk and Lua, i’m tryng to create a sort of wheel of fortune game, but i’m having trouble with the rotation physics. My wheel rotate when i touch it but stops immediatly after. I would like to give to the wheel a spin effect that slowly decrease the speed just like in the wheel of fortune. Here is my code:

---

–

– main.lua

–

---

– 

local physics = require(“physics”)

physics.start()

physics.setGravity(0,8)

physics.setDrawMode(“hybrid”)

local background = display.newImage(“background.png”)

background.x = display.contentCenterX

background.y = display.contentCenterY

local arms = display.newImage(“arms1.png”, true)

arms.x = display.contentWidth - 134

arms.y = display.contentHeight - 290

local wheel = display.newImage(“wheel.png”, true)

wheel.x = display.contentWidth - 195

wheel.y = display.contentHeight - 268

physics.addBody(wheel,“static”,{bounce=0, friction=0.2, radius=98})

wheel:applyTorque(3.8)

local skull = display.newImage(“skull1.png”, true)

skull.x = display.contentWidth - 190

skull.y = display.contentHeight - 379

function getAngle(x1,y1,x2,y2)

    local PI = 3.14159265358

    local deltaY = y2 - y1

    local deltaX = x2 - x1

    local angleInDegrees = (math.atan2( deltaY, deltaX) * 180 / PI)*-1

    local mult = 10^0

    return math.floor(angleInDegrees * mult + 0.5) / mult

end

wheel.touch = function(self, event)

    print(event.phase)

    if event.phase == “moved” then

        --If your image is originally pointing to the north use +90

        --If your image is originally pointing to the east use +180

        --If your image is originally pointing to the south use +270

        --If your image is originally pointing to the west use +360 or +0

        --My wheel.png is point to the east so I use +180

        --You can use this formula

        wheel.rotation = (getAngle(wheel.x,wheel.y,event.x,event.y)+180)*-1

    end

end

Runtime:addEventListener(“touch”,wheel)

---

Thanks and i’m sorry for my bad english.

[bjsorrentino]

Hi @kkaaoss,
First and most importantly, make the wheel a “dynamic” physics body, not “static”.

Next, apply the torque just as you are now, however, to make the wheel slow down gradually, set an angular damping value on it:

https://docs.coronalabs.com/api/type/Body/angularDamping.html

Best regards,
Brent

[kkaaoss]

Hi Brent!

Thanks for your reply, i just applied changes to my code as you suggested, but the wheel still stops immediatly and now the wheel falls down here is my new code:

 -----------------------------------------------------------------------------------------

–

– main.lua

–

---

– 

local physics = require(“physics”)

physics.start()

physics.setGravity(0,1)

physics.setDrawMode(“hybrid”)

local background = display.newImage(“background.png”)

background.x = display.contentCenterX

background.y = display.contentCenterY

local arms = display.newImage(“arms1.png”, true)

arms.x = display.contentWidth - 134

arms.y = display.contentHeight - 290

local wheel = display.newImage(“wheel.png”, true)

wheel.x = display.contentWidth - 195

wheel.y = display.contentHeight - 268

physics.addBody(wheel,“dynamic”,{bounce=0, friction=0.2, radius=98})

wheel.angularDamping = 5

wheel:applyTorque(3.8)

local skull = display.newImage(“skull1.png”, true)

skull.x = display.contentWidth - 190

skull.y = display.contentHeight - 379

function getAngle(x1,y1,x2,y2)

    local PI = 3.14159265358

    local deltaY = y2 - y1

    local deltaX = x2 - x1

    local angleInDegrees = (math.atan2( deltaY, deltaX) * 180 / PI)*-1

    local mult = 10^0

    return math.floor(angleInDegrees * mult + 0.5) / mult

end

wheel.touch = function(self, event)

    print(event.phase)

    if event.phase == “moved” then

        --If your image is originally pointing to the north use +90

        --If your image is originally pointing to the east use +180

        --If your image is originally pointing to the south use +270

        --If your image is originally pointing to the west use +360 or +0

        --My wheel.png is point to the east so I use +180

        --You can use this formula

        wheel.rotation = (getAngle(wheel.x,wheel.y,event.x,event.y)+180)*-1

    end

end

Runtime:addEventListener(“touch”,wheel)

---

[rob]

Please post your code using the <> button in the forum editor’s formatting bar (with Bold, Italic, etc.).

I built a triva game once that uses a wheel of fortune type spinning well to select categories. You can spin it and take where it lands, but you can also use it a dial to pick the category.  Here is the relevant code:

local function gameLoop() angle = wheel.rotation if wheel.angularVelocity == 0 and angle ~= startingAngle then --print(angle % 360) local wedge = math.floor(((angle + 45) % 360) /45) + 1 --print(wedge .. " " .. wedgeName[wedge]) startingAngle = angle mydata.gameCategory = wedge if movementEnded then timer.performWithDelay(1000,playRound); end end end local function spinWheel(event) local t = event.target local phase = event.phase --print("Phase: " .. phase) if (phase == "began") then display.getCurrentStage():setFocus( t ) t.isFocus = true -- Store initial position of finger t.x1 = event.x t.y1 = event.y startTime = event.time --print("start time " .. startTime) elseif t.isFocus then if (phase == "moved") then t.x2 = event.x t.y2 = event.y angle1 = 180/math.pi \* math.atan2(t.y1 - t.y , t.x1 - t.x) angle2 = 180/math.pi \* math.atan2(t.y2 - t.y , t.x2 - t.x) --print("angle1 = "..angle1) rotationAmt = angle1 - angle2 --rotate it t.rotation = t.rotation - rotationAmt --print ("t.rotation = "..t.rotation) t.x1 = t.x2 t.y1 = t.y2 elseif (phase == "ended") or (phase == "cancelled") then local deltaTime = event.time - startTime if deltaTime \< 500 then wheel:applyAngularImpulse( 100000 + rand(33000)) wheel:removeEventListener("touch", spinWheel) else --print("delta time " .. (event.time - startTime)) -- wheel:removeEventListener("touch", spinWheel) timer.performWithDelay(500,playRound); end movementEnded = true display.getCurrentStage():setFocus( nil ) t.isFocus = false end end -- Stop further propagation of touch event return true end function scene:createScene( event ) local group = self.view physics.start() physics.setGravity(0,0) -- app doesn't need gravity physics.pause() local background = display.newImageRect("images/menu\_background.jpg", 756, 504) background.x = display.contentWidth / 2 background.y = display.contentHeight / 2 group:insert(background) --\> This sets the background wheel = display.newImageRect("images/wheel.png", 250, 250) startingAngle = wheel.rotation print("Starting Angle: " .. startingAngle) wheel.x = 140 wheel.y = display.contentHeight / 2 + 20 group:insert(wheel) physics.addBody(wheel, {density=0.5, friction=0.8, bounce=0.0, radius=125 } ) wheel.angularDamping = 0.7 wheel:addEventListener("touch", spinWheel) local pointer = display.newImageRect("images/pointer.png", 32, 16) pointer.x = 15 pointer.y = display.contentHeight / 2 + 20 group:insert(pointer) -- more code end function scene:enterScene( event ) local group = self.view storyboard.removeScene("loading") Runtime:addEventListener("enterFrame", gameLoop) physics.start() end

As I said, this is an older app that was using storyboard, but this should adapt to Composer quite easily.

Rob

[kkaaoss]

^{Hello Rob,}

^{First of all thank you for the code! I resolved the “falling wheel” issue setting the gravity to zero, but i still have the touch event issue.}

^{I need to spin the wheel with the finger, now it follows my finger on the screen but when i remove the finger it stops instead of continue spinning.}

^{Thank you guys for the help.}

[rob]

My touch handler works. Take some time and study it. It also uses an Runtime “enterFrame” listener too. 

Rob

[kkaaoss]

Hi Everybody,

Rob I switched your code with mine but my wheel still stops :-((((( please help i’m losing my head.

here is my new code:

[lua]         --print(wedge … " " … wedgeName[wedge])

        startingAngle = angle

        if movementEnded then timer.performWithDelay(1000,playRound); end

    end

end

local function spinObject(event)

    local t = event.target

    local phase = event.phase

    --print("Phase: " … phase)

    if (phase == “began”) then

            display.getCurrentStage():setFocus( t )

            t.isFocus = true

            – Store initial position of finger

            t.x1 = event.x

            t.y1 = event.y

    elseif t.isFocus then

            if (phase == “moved”) then

                    t.x2 = event.x

                    t.y2 = event.y

                    local angle1 = 180/math.pi * math.atan2(t.y1 - t.y , t.x1 - t.x)

                    local angle2 = 180/math.pi * math.atan2(t.y2 - t.y , t.x2 - t.x)

                    local rotationAmt = angle1 - angle2

                    t.rotation = t.rotation - rotationAmt

                    t.x1 = t.x2

                    t.y1 = t.y2

                    

            elseif (phase == “ended”) or (phase == “cancelled”) then

                display.getCurrentStage():setFocus( nil )

                t.isFocus = false

            end

    end

    

    – Stop further propagation of touch event

    return true

end

wheel:addEventListener(“touch”, spinObject)

Runtime:addEventListener(“enterFrame”, gameLoop)

    physics.start() [/lua]

[kkaaoss]

Ok we can close the topic as ‘Solved’ i found a solution to my issue using the “touch joint”.

Thanks everybody for the precious help.

[bjsorrentino]

Hi @kkaaoss,
First and most importantly, make the wheel a “dynamic” physics body, not “static”.

Next, apply the torque just as you are now, however, to make the wheel slow down gradually, set an angular damping value on it:

https://docs.coronalabs.com/api/type/Body/angularDamping.html

Best regards,
Brent

[kkaaoss]

Hi Brent!

Thanks for your reply, i just applied changes to my code as you suggested, but the wheel still stops immediatly and now the wheel falls down here is my new code:

 -----------------------------------------------------------------------------------------

–

– main.lua

–

---

– 

local physics = require(“physics”)

physics.start()

physics.setGravity(0,1)

physics.setDrawMode(“hybrid”)

local background = display.newImage(“background.png”)

background.x = display.contentCenterX

background.y = display.contentCenterY

local arms = display.newImage(“arms1.png”, true)

arms.x = display.contentWidth - 134

arms.y = display.contentHeight - 290

local wheel = display.newImage(“wheel.png”, true)

wheel.x = display.contentWidth - 195

wheel.y = display.contentHeight - 268

physics.addBody(wheel,“dynamic”,{bounce=0, friction=0.2, radius=98})

wheel.angularDamping = 5

wheel:applyTorque(3.8)

local skull = display.newImage(“skull1.png”, true)

skull.x = display.contentWidth - 190

skull.y = display.contentHeight - 379

function getAngle(x1,y1,x2,y2)

    local PI = 3.14159265358

    local deltaY = y2 - y1

    local deltaX = x2 - x1

    local angleInDegrees = (math.atan2( deltaY, deltaX) * 180 / PI)*-1

    local mult = 10^0

    return math.floor(angleInDegrees * mult + 0.5) / mult

end

wheel.touch = function(self, event)

    print(event.phase)

    if event.phase == “moved” then

        --If your image is originally pointing to the north use +90

        --If your image is originally pointing to the east use +180

        --If your image is originally pointing to the south use +270

        --If your image is originally pointing to the west use +360 or +0

        --My wheel.png is point to the east so I use +180

        --You can use this formula

        wheel.rotation = (getAngle(wheel.x,wheel.y,event.x,event.y)+180)*-1

    end

end

Runtime:addEventListener(“touch”,wheel)

---

[rob]

Please post your code using the <> button in the forum editor’s formatting bar (with Bold, Italic, etc.).

I built a triva game once that uses a wheel of fortune type spinning well to select categories. You can spin it and take where it lands, but you can also use it a dial to pick the category.  Here is the relevant code:

local function gameLoop() angle = wheel.rotation if wheel.angularVelocity == 0 and angle ~= startingAngle then --print(angle % 360) local wedge = math.floor(((angle + 45) % 360) /45) + 1 --print(wedge .. " " .. wedgeName[wedge]) startingAngle = angle mydata.gameCategory = wedge if movementEnded then timer.performWithDelay(1000,playRound); end end end local function spinWheel(event) local t = event.target local phase = event.phase --print("Phase: " .. phase) if (phase == "began") then display.getCurrentStage():setFocus( t ) t.isFocus = true -- Store initial position of finger t.x1 = event.x t.y1 = event.y startTime = event.time --print("start time " .. startTime) elseif t.isFocus then if (phase == "moved") then t.x2 = event.x t.y2 = event.y angle1 = 180/math.pi \* math.atan2(t.y1 - t.y , t.x1 - t.x) angle2 = 180/math.pi \* math.atan2(t.y2 - t.y , t.x2 - t.x) --print("angle1 = "..angle1) rotationAmt = angle1 - angle2 --rotate it t.rotation = t.rotation - rotationAmt --print ("t.rotation = "..t.rotation) t.x1 = t.x2 t.y1 = t.y2 elseif (phase == "ended") or (phase == "cancelled") then local deltaTime = event.time - startTime if deltaTime \< 500 then wheel:applyAngularImpulse( 100000 + rand(33000)) wheel:removeEventListener("touch", spinWheel) else --print("delta time " .. (event.time - startTime)) -- wheel:removeEventListener("touch", spinWheel) timer.performWithDelay(500,playRound); end movementEnded = true display.getCurrentStage():setFocus( nil ) t.isFocus = false end end -- Stop further propagation of touch event return true end function scene:createScene( event ) local group = self.view physics.start() physics.setGravity(0,0) -- app doesn't need gravity physics.pause() local background = display.newImageRect("images/menu\_background.jpg", 756, 504) background.x = display.contentWidth / 2 background.y = display.contentHeight / 2 group:insert(background) --\> This sets the background wheel = display.newImageRect("images/wheel.png", 250, 250) startingAngle = wheel.rotation print("Starting Angle: " .. startingAngle) wheel.x = 140 wheel.y = display.contentHeight / 2 + 20 group:insert(wheel) physics.addBody(wheel, {density=0.5, friction=0.8, bounce=0.0, radius=125 } ) wheel.angularDamping = 0.7 wheel:addEventListener("touch", spinWheel) local pointer = display.newImageRect("images/pointer.png", 32, 16) pointer.x = 15 pointer.y = display.contentHeight / 2 + 20 group:insert(pointer) -- more code end function scene:enterScene( event ) local group = self.view storyboard.removeScene("loading") Runtime:addEventListener("enterFrame", gameLoop) physics.start() end

As I said, this is an older app that was using storyboard, but this should adapt to Composer quite easily.

Rob

[kkaaoss]

^{Hello Rob,}

^{First of all thank you for the code! I resolved the “falling wheel” issue setting the gravity to zero, but i still have the touch event issue.}

^{I need to spin the wheel with the finger, now it follows my finger on the screen but when i remove the finger it stops instead of continue spinning.}

^{Thank you guys for the help.}

[rob]

My touch handler works. Take some time and study it. It also uses an Runtime “enterFrame” listener too. 

Rob

[kkaaoss]

Hi Everybody,

Rob I switched your code with mine but my wheel still stops :-((((( please help i’m losing my head.

here is my new code:

[lua]         --print(wedge … " " … wedgeName[wedge])

        startingAngle = angle

        if movementEnded then timer.performWithDelay(1000,playRound); end

    end

end

local function spinObject(event)

    local t = event.target

    local phase = event.phase

    --print("Phase: " … phase)

    if (phase == “began”) then

            display.getCurrentStage():setFocus( t )

            t.isFocus = true

            – Store initial position of finger

            t.x1 = event.x

            t.y1 = event.y

    elseif t.isFocus then

            if (phase == “moved”) then

                    t.x2 = event.x

                    t.y2 = event.y

                    local angle1 = 180/math.pi * math.atan2(t.y1 - t.y , t.x1 - t.x)

                    local angle2 = 180/math.pi * math.atan2(t.y2 - t.y , t.x2 - t.x)

                    local rotationAmt = angle1 - angle2

                    t.rotation = t.rotation - rotationAmt

                    t.x1 = t.x2

                    t.y1 = t.y2

                    

            elseif (phase == “ended”) or (phase == “cancelled”) then

                display.getCurrentStage():setFocus( nil )

                t.isFocus = false

            end

    end

    

    – Stop further propagation of touch event

    return true

end

wheel:addEventListener(“touch”, spinObject)

Runtime:addEventListener(“enterFrame”, gameLoop)

    physics.start() [/lua]

[kkaaoss]

Ok we can close the topic as ‘Solved’ i found a solution to my issue using the “touch joint”.

Thanks everybody for the precious help.