How to get rotation of an object with respect to x axis

Comments

• petec Member

  May 2014

  To keep the rotation of object1 in the 360 degree range you could do something like:

  if object1:getRotation()>360 then object1:setRotation(object1:getRotation()-360) end

  If object2 is your character and if that is always upright then its rotation will be 0. I guess you must have an angle value for where the character is around your ellipse in the equation you are using to make it follow that path.

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• simran Member

  May 2014

  @petec : Yes, Right. I have used eclipse equation translate the character along the eclipse, its angle is always 0, but how do I get the angle value for the character?

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• petec Member

  May 2014

  Presumably you are using an angle that keeps increasing to move the character around the ellipse. If so, don't you already have an angle value for where the character is around the ellipse?

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• HubertRonald Member

  May 2014 edited May 2014

  Hi @simran
  I was reading your case and found it interesting (I love the clock problems).
  so I have developed a code which I hope will help you better manage Gideros

  --------------------------------------------- -- COLOR: RGB TO HEX --------------------------------------------- function rgb(r, g, b) return ((r*256)+g)*256+b end   --------------------------------------------- -- SET BACKGROUND --------------------------------------------- application:setBackgroundColor(rgb(0, 0, 0))     ---------------------------------------- -- LOCK ORIENTATION ---------------------------------------- stage:setOrientation(Stage.PORTRAIT)     ---------------------------------------- -- FIX DIMENSION DEVICE ---------------------------------------- _W, _H = application:getContentWidth(), application:getContentHeight() Wdx = application:getLogicalTranslateX() / application:getLogicalScaleX() Hdy = application:getLogicalTranslateY() / application:getLogicalScaleY()     --[[ ---------------------------------------- -- CLASS DRAW ARC ---------------------------------------- -- thanks to <a href="http://forum.giderosmobile.com/profile/ndoss" rel="nofollow">@ndoss</a> -- <a href="http://giderosmobile.com/forum/discussion/346/snippet-arccircleellipse#Item_1" rel="nofollow">http://giderosmobile.com/forum/discussion/346/snippet-arccircleellipse#Item_1</a> ]] Arc = gideros.class(Shape) function Arc:init(t) local x = t.x or t.y or 0 local y = t.y or t.x or 0 local fillStyle = t.fillStyle or { Shape.SOLID, 0x000000, 0.5 } local lineStyle = t.lineStyle or { 2, 0xffffff, 0.5 } local xradius = t.xradius or t.radius or 100 local yradius = t.yradius or t.radius or 100 local sides = t.sides or (xradius + yradius)/2 local startAngle = t.startAngle or 0 local arcAngle = t.arcAngle or 1   self:setFillStyle(unpack(fillStyle)) self:setLineStyle(unpack(lineStyle))   local angleStep = arcAngle / sides   self:setPosition(x,y) local xx = math.cos(startAngle*2*math.pi) * xradius local yy = math.sin(startAngle*2*math.pi) * yradius   self:beginPath() self:moveTo(xx, yy) for i = 1,sides do local angle = startAngle + i * angleStep self:lineTo(math.cos(angle*2*math.pi) * xradius, math.sin(angle*2*math.pi) * yradius) end self:endPath()   if t.alpha then self:setAlpha(t.alpha) end if t.parent then t.parent:addChild(self) end   return self end     ---------------------------------------- -- DRAW ELLIPSE ---------------------------------------- local radiusY = 300 -- y local radiusX = 74 -- x Arc.new{x=_W/2+2*radiusX,y=_H/2+radiusY,xradius=radiusX, yradius=radiusY, sides=sides, fillStyle = { Shape.SOLID, rgb(200, 200, 200), 0.3 }, lineStyle = { 0, rgb(200, 200, 200), 0.3 }, parent = stage}       ---------------------------------------- -- CLASS DRAW SEGMENT ---------------------------------------- Segment = Core.class(Shape)   function Segment:init(config) -- Settings to control the line self.conf = { Width = 1.5, Color = rgb(255, 255, 255), Alpha = 1, }   if config then --copying configuration for key,value in pairs(config) do self.conf[key]= value end end   self:setVisible(false) end   -- Draw line function Segment:draw(dots) self:beginPath() self:setLineStyle(self.conf.Width, self.conf.Color, self.conf.Alpha) self:moveTo(dots.x[1],dots.y[1]) self:lineTo(dots.x[2],dots.y[2]) self:endPath() self:setVisible(true) end   -- hide line function Segment:hide() self:clear() self:setVisible(false) end     ---------------------------------------- -- DRAW NEEDLE ---------------------------------------- local needle = Segment.new() stage:addChild(needle) needle:draw({x={_W/2+2*radiusX, _W/2+2*radiusX},y={_H/2+radiusY, _H/2}})     ---------------------------------------- -- FRAME CLOCK CONFIG ---------------------------------------- local cos = math.cos local sin = math.sin local rad = math.rad countFPS = 0 -- 60 ~= 1 sec theta = 270 -- Reference of axes in mobile is different   stage:addEventListener(Event.ENTER_FRAME, function() countFPS = countFPS + 1 if countFPS == 10 then -- change 10 if you need more or less velocity needle:hide() theta = theta + 1   needle:draw({ x={_W/2+2*radiusX, _W/2+2*radiusX+radiusX*cos(rad(theta))}, y={_H/2+radiusY, _H/2+radiusY+radiusY*sin(rad(theta))} }) countFPS = 0 end   end)

  
  you can download this source from here too
  https://github.com/HubertRonald/Clock_Ellipse/blob/master/main.lua
  
  Bye >-

  
  [-] Liasoft

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• simran Member

  May 2014

  Hey, thanks a ton for that but what I am really stuck at is detecting collision of needle with a character that is translating around an ellipse all the time, and I am totally stuck at it

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