Rotated coordinates

General
1

I have a sprite that rotates as it rolls around and I’m trying to add a bounce functionality that moves it up then back down but when I try to bounce it bounces in the direction it is rotated to. I am trying to get it to always bounce up, no matter how it is rotated. Anyone have any idea how to do this?

Here is some example code of what I have so far:


--# Main
-- Bounce

-- Use this function to perform your initial setup
function setup()
    debugea()
    createBallImage()
    ball = Sprite(ballImg, 0,0, ballImg.width, ballImg.height)
end

function createBallImage()
    ballImg = image(100,100)
    setContext(ballImg)
    fill(255,255,0)
    ellipse(50,50, 100, 100)
    sprite("Platformer Art:Guy Standing", 50, 50, 75)
    setContext()
end

function bounce(obj)
    height = 100
    hold = 0.1
    
    local m = obj
    local savedScale = vec2(1,1)
    local savedPos = obj.pos
    local size = obj.size
    local squash = vec2(1.5, 0.75)
    local moveDown = savedPos.y - size.y/2 * (1 - squash.y)
    
    tween(0.15, m, {scale = squash}, tween.easing.quadInOut)
    tween(0.15, m, {pos = vec2(savedPos.x, moveDown)}, tween.easing.quadInOut,
        function()
            local moveUp = savedPos.y + height * 0.9
            local unsquash = vec2(0.85, 1.25)
            
            tween(0.15, m, {scale = unsquash}, tween.easing.quadInOut)
            tween(0.2, m, {pos = vec2(savedPos.x, moveUp)}, tween.easing.quadOut,
                function()
                    -- Reached top of jump
                    
                    local holdHeight = savedPos.y + height
                    tween(hold, m, {pos = vec2(savedPos.x, holdHeight)}, tween.easing.linear,
                     function()
                        tween(0.15, m, {scale = savedScale}, tween.easing.quadInOut)
                        tween(0.15, m, {pos = savedPos}, tween.easing.quadIn)
                     end)
                end )
            
        end )
        --
end


-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(40, 40, 50)

    -- This sets the line thickness
    strokeWidth(5)

    -- Do your drawing here
    ball.angle = ball.angle + 1
    pushMatrix()
    translate(WIDTH/4, HEIGHT/2)
    rotate(ball.angle)
    ball:draw()
    popMatrix()
end

function touched(touch)
    if touch.state == ENDED then
        bounce(ball)
    end
end

--# Sprite
Sprite = class()

function Sprite:init(img, x, y, width, height)
    -- you can accept and set parameters here
    self.img = img
    self.pos = vec2(x,y)
    self.size = vec2(width, 0)
    self.size.y = height or width
    self.scale = vec2(1,1)
    self.angle = 0
    self.fill = color(255)
end

function Sprite:draw()
    pushStyle()
    pushMatrix()
    fill(self.fill) noStroke()
    sprite(self.img, self.pos.x, self.pos.y, self.size.x * self.scale.x, self.size.y * self.scale.y)
    popMatrix()
    popStyle()
end
2

When you say ‘a sprite’ do you mean a physics object?
If you post the code, it would be easier to understand why it doesnt work…

3

@Jmv38, my apologies, I have added some example code above

4

I think this does whar you want. See changes:


--# Main
-- Bounce

-- Use this function to perform your initial setup
function setup()
   -- debugea()
    createBallImage()
    ball = Sprite(ballImg, 0,0, ballImg.width, ballImg.height)
end

function createBallImage()
    ballImg = image(100,100)
    setContext(ballImg)
    fill(255,255,0)
    ellipse(50,50, 100, 100)
    sprite("Platformer Art:Guy Standing", 50, 50, 75)
    setContext()
end

function bounce(obj)
    height = 100
    hold = 0.1

    local m = obj
    local savedScale = vec2(1,1)
    local savedPos = obj.pos
    local size = obj.size
    local squash = vec2(1.5, 0.75)
    local moveDown = savedPos.y - size.y/2 * (1 - squash.y)

    tween(0.15, m, {scale = squash}, tween.easing.quadInOut)
    tween(0.15, m, {pos = vec2(savedPos.x, moveDown)}, tween.easing.quadInOut,
        function()
            local moveUp = savedPos.y + height * 0.9
            local unsquash = vec2(0.85, 1.25)

            tween(0.15, m, {scale = unsquash}, tween.easing.quadInOut)
            tween(0.2, m, {pos = vec2(savedPos.x, moveUp)}, tween.easing.quadOut,
                function()
                    -- Reached top of jump

                    local holdHeight = savedPos.y + height
                    tween(hold, m, {pos = vec2(savedPos.x, holdHeight)}, tween.easing.linear,
                     function()
                        tween(0.15, m, {scale = savedScale}, tween.easing.quadInOut)
                        tween(0.15, m, {pos = savedPos}, tween.easing.quadIn)
                     end)
                end )

        end )
        --
end


-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(40, 40, 50)

    -- This sets the line thickness
    strokeWidth(5)

    -- Do your drawing here
    ball.angle = ball.angle + 1
    pushMatrix()
    translate(WIDTH/4, HEIGHT/2)
--    rotate(ball.angle)    -- changes
    ball:draw()
    popMatrix()
end

function touched(touch)
    if touch.state == ENDED then
        bounce(ball)
    end
end

--# Sprite
Sprite = class()

function Sprite:init(img, x, y, width, height)
    -- you can accept and set parameters here
    self.img = img
    self.pos = vec2(x,y)
    self.size = vec2(width, 0)
    self.size.y = height or width
    self.scale = vec2(1,1)
    self.angle = 0
    self.fill = color(255)
end

function Sprite:draw()
    pushStyle()
    pushMatrix()
    fill(self.fill) noStroke()
    -- changes
    translate(self.pos.x, self.pos.y) 
    scale(self.scale.x, self.scale.y)
    rotate(ball.angle)
    sprite(self.img)
    -- changes
    popMatrix()
    popStyle()
end
5

ps: Replace ball by self in rotate

6

@Jmv38, Thanks!