Rotating Sun In Codea

Main

-- CircleMask class courtesy of Simeon (http://twolivesleft.com/Codea/Talk/profile/3/Simeon)

-- Use this function to perform your initial setup
function setup()
    print("Hello World!")
    -- params: width, sides in mesh, texture detail, image resolution, rotation speed
    sun = Sun(WIDTH*0.5, 128, 580, 52, 0.4)
end

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

    -- Do your drawing here
    sun:draw()
end

----

CircleMask = class()

function CircleMask:init(rad, sides)
    -- you can accept and set parameters here
    self.mesh = mesh()

    local verts = {}
    local tex = {}

    for i=1,sides do
        local r1 = (i-1)/sides * math.pi * 2
        local r2 = i/sides * math.pi * 2

        local p1 = vec2( math.cos(r1), math.sin(r1) )
        local p2 = vec2( math.cos(r2), math.sin(r2) )

        -- Verts
        table.insert(verts, p1 * rad)
        table.insert(verts, p2 * rad)
        table.insert(verts, vec2(0,0)) -- center

        -- Tex Coords
        table.insert(tex, (p1 + vec2(1,1)) * 0.5)
        table.insert(tex, (p2 + vec2(1,1)) * 0.5)
        table.insert(tex, vec2(0.5,0.5))
    end

    self.mesh.vertices = verts
    self.mesh.texCoords = tex

    self.mesh:setColors( 255,255,255 )
end

function CircleMask:setDrawFunction(func, w, h)
    self.mesh.texture = image(w,h)
    self.drawFunction = func
end

function CircleMask:setTexture(tex)
    self.mesh.texture = tex
    self.drawFunction = nil
end

function CircleMask:draw()
    if self.drawFunction ~= nil then
        setContext( self.mesh.texture )
        pushMatrix()
        resetMatrix()

        self.drawFunction()

        popMatrix()
        setContext()
    end

    self.mesh:draw()
end

----

Sun = class()

function Sun:init(diameter, sides, spotDetail, resolution, speed)
    self.initialHeight = diameter
    self.sunMask = CircleMask(self.initialHeight/2, sides)
    self.numSpots = spotDetail
    self.sunImgSize = resolution -- image resolution. Also impacts rotation speed
    self.sunRot = 0 -- initial rotation
    self.sunRotSpeed = speed -- rotations speed, pixels per frame
    self.maxSunRot = self.initialHeight
    self.sunMask:setDrawFunction(function()
                                    self:drawRotatingTexture(self.sunImgSize)
                                 end, self.sunImgSize, self.sunImgSize)
    
end

function Sun:drawMasked()
    pushStyle()
    pushMatrix()
    resetMatrix()
    translate(WIDTH/2, HEIGHT/2)
    col = randomSunColour()
    tint(col)
    self.sunMask:draw()
    popMatrix()
    popStyle()
end

function Sun:draw()
    self:drawMasked()
end

function randomSunColour()
    red = math.random(10) + 240
    green = math.random(10) + 160
    col = color(red, green, 0, 255)
    return col
end

function randomGray()
    lum = math.random(30) + 220
    col = color(lum, lum, lum, 128)
    return col
end

function Sun:drawRotatingTexture(size)
    
    self:createSunImage(size*2, size)
    x = (size/2) - self.sunRot
    y = size/2
    w = size * 2
    h = size
    self.sunRot = (self.sunRot +  self.sunRotSpeed) % w
    clip(0,0,size,size)
    sprite(self.circleImg, x, y, w ,h)
    sprite(self.circleImg, x + w - 1, y, w, h)
    clip()
end

function Sun:drawSunTexture(w, h)
    
    pushStyle()
    noStroke()
    fill(32, 32, 32, 255) -- fill white, we can tint() the image
    ellipseMode(CORNERS)
    rect(0,0,w,h)
    
    for i=0, self.numSpots do
        x = math.random(w)
        y = math.random(h)
        ew = math.random(h/2)
        eh = math.random(h/2)
        fill(randomGray())
        ellipseMode(CENTER)
        ellipse(x, y, ew, eh)
        -- make repeatable horizontally
        ellipse(x+w, y, ew, eh)
        ellipse(x-w, y, ew, eh)
    end
    
    popStyle()
end

function Sun:createSunImage( w, h )
    if self.circleImg ~= nil then
        return
    end
    
    local i = image(w, h)
    setContext(i)
    self:drawSunTexture(w, h)
    setContext()
    self.circleImg = i
end