WaterBob

Main.lua

-- Water Bob

-- Use this function to perform your initial setup
local water
local box

function setup()
    print("alright let's do this!")
    debugDraw = PhysicsDebugDraw()
    
    createGround()
    box = createBox(WIDTH/2, 100, 30, 30)
    -- createCircle(WIDTH/2 + 50, 110, 30)
    -- createRandPoly(WIDTH/2 + 150, 120)
    water = Water(createBox(WIDTH/2, 50, WIDTH, 100))
    camera = 0
end

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

    -- Do your drawing here
    pushMatrix() 
    
    camera = -box.x + WIDTH*0.5
    translate(camera, 0)
    
    water:draw()
    debugDraw:draw()
    
    popMatrix()
    
    
end

function createCircle(x,y,r)
    local circle = physics.body(CIRCLE, r)
    -- enable smooth motion
    circle.interpolate = true
    circle.x = x
    circle.y = y
    circle.restitution = 0.25
    circle.sleepingAllowed = false
    debugDraw:addBody(circle)
    return circle
end

function createBox(x,y,w,h)
    -- polygons are defined by a series of points in counter-clockwise order
    local box = physics.body(POLYGON, vec2(-w/2,h/2), vec2(-w/2,-h/2), vec2(w/2,-h/2), vec2(w/2,h/2))
    box.interpolate = true
    box.x = x
    box.y = y
    box.restitutions = 0.25
    box.sleepingAllowed = false
    debugDraw:addBody(box)
    return box
end

function createGround()
    local ground = physics.body(POLYGON, vec2(0,20), vec2(0,0), vec2(WIDTH,0), vec2(WIDTH,20))
    ground.type = STATIC
    debugDraw:addBody(ground)
    return ground
end

function createRandPoly(x,y)
    local count = math.random(3,10)
    local r = math.random(25,75)
    local a = 0
    local d = 2 * math.pi / count
    local points = {}
    
    for i = 1,count do
        local v = vec2(r,0):rotate(a) + vec2(math.random(-10,10), math.random(-10,10))
        a = a + d
        table.insert(points, v)
    end
    
    local poly = physics.body(POLYGON, unpack(points))
    poly.x = x
    poly.y = y
    poly.sleepingAllowed = false
    poly.restitution = 0.25
    debugDraw:addBody(poly)
    return poly
end

function touched(touch)
    if debugDraw:touched(touch) == false then
        -- currentTest:touched(touch)
    end
end

function collide(contact)
    if debugDraw then
        if contact.bodyA.sensor or contact.bodyB.sensor then
            water:collide(contact)
        end
    end
end

PhysicsDebugDraw.lua

PhysicsDebugDraw = class()

function PhysicsDebugDraw:init()
    self.bodies = {}
    self.joints = {}
    self.touchMap = {}
    self.contacts = {}
end

function PhysicsDebugDraw:addBody(body)
    table.insert(self.bodies,body)
end

function PhysicsDebugDraw:addJoint(joint)
    table.insert(self.joints,joint)
end

function PhysicsDebugDraw:clear()
    -- deactivate all bodies
    
    for i,body in ipairs(self.bodies) do
        body:destroy()
    end
  
    for i,joint in ipairs(self.joints) do
        joint:destroy()
    end      
    
    self.bodies = {}
    self.joints = {}
    self.contacts = {}
    self.touchMap = {}
end

function PhysicsDebugDraw:draw()
    
    pushStyle()
    smooth()
    strokeWidth(5)
    stroke(128,0,128)
    
    local gain = 2.0
    local damp = 0.5
    for k,v in pairs(self.touchMap) do
        local worldAnchor = v.body:getWorldPoint(v.anchor)
        local touchPoint = v.tp
        local diff = touchPoint - worldAnchor
        local vel = v.body:getLinearVelocityFromWorldPoint(worldAnchor)
        v.body:applyForce( (1/1) * diff * gain - vel * damp, worldAnchor)
        
        line(touchPoint.x, touchPoint.y, worldAnchor.x, worldAnchor.y)
    end
    
    stroke(0,255,0,255)
    strokeWidth(5)
    for k,joint in pairs(self.joints) do
        local a = joint.anchorA
        local b = joint.anchorB
        line(a.x,a.y,b.x,b.y)
    end
    
    stroke(255,255,255,255)
    noFill()
    
    
    for i,body in ipairs(self.bodies) do
        pushMatrix()
        translate(body.x, body.y)
        rotate(body.angle)
    
        if body.type == STATIC then
            stroke(255,255,255,255)
        elseif body.type == DYNAMIC then
            stroke(150,255,150,255)
        elseif body.type == KINEMATIC then
            stroke(150,150,255,255)
        end
    
        if body.shapeType == POLYGON then
            strokeWidth(3.0)
            local points = body.points
            for j = 1,#points do
                a = points[j]
                b = points[(j % #points)+1]
                line(a.x, a.y, b.x, b.y)
            end
        elseif body.shapeType == CHAIN or body.shapeType == EDGE then
            strokeWidth(3.0)
            local points = body.points
            for j = 1,#points-1 do
                a = points[j]
                b = points[j+1]
                line(a.x, a.y, b.x, b.y)
            end      
        elseif body.shapeType == CIRCLE then
            strokeWidth(3.0)
            line(0,0,body.radius-3,0)            
            ellipse(0,0,body.radius*2)
        end
        
        popMatrix()
    end 
    
    stroke(255, 0, 0, 255)
    fill(255, 0, 0, 255)

    for k,v in pairs(self.contacts) do
        for m,n in ipairs(v.points) do
            ellipse(n.x, n.y, 10, 10)
        end
    end
    
    popStyle()
end

function PhysicsDebugDraw:touched(touch)
    local touchPoint = vec2(touch.x, touch.y)
    if touch.state == BEGAN then
        for i,body in ipairs(self.bodies) do
            if body.type == DYNAMIC and body:testPoint(touchPoint) then
                self.touchMap[touch.id] = {tp = touchPoint, body = body, anchor = body:getLocalPoint(touchPoint)} 
                return true
            end
        end
    elseif touch.state == MOVING and self.touchMap[touch.id] then
        self.touchMap[touch.id].tp = touchPoint
        return true
    elseif touch.state == ENDED and self.touchMap[touch.id] then
        self.touchMap[touch.id] = nil
        return true;
    end
    return false
end

function PhysicsDebugDraw:collide(contact)
    if contact.state == BEGAN then
        self.contacts[contact.id] = contact
        sound(SOUND_HIT, 2643)
    elseif contact.state == MOVING then
        self.contacts[contact.id] = contact
    elseif contact.state == ENDED then
        self.contacts[contact.id] = nil
    end
end

Water.lua

Water = class()

function Water:init(body)
    -- you can accept and set parameters here
    self.body = body
    self.body.sensor = true
    self.body.type = STATIC
    -- self.body.restitution = -7
    self.bodies = {}
end

function Water:draw()
    -- Codea does not automatically call this method
    for k,body in ipairs(self.bodies) do
        body:applyForce(vec2(0,20))
        
        print(body.linearVelocity)
    end
end

function Water:touched(touch)
    -- Codea does not automatically call this method
end

function Water:add(body)
    table.insert(self.bodies, body)
    body.linearDamping = 3
    body.angularDamping = 5
end

function Water:remove(body)
    for k, b in ipairs(self.bodies) do
        if b == body then
            table.remove(self.bodies, k)
            break
        end
    end
    body.linearDamping = 0
    body.angularDamping = 0
end

function Water:collide(contact)
    if debugDraw then
        local body
       
        if contact.bodyA.sensor then
            body = contact.bodyB
        elseif contact.bodyB.sensor then
            body = contact.bodyA
        end
        
        if contact.state == BEGAN then
            self:add(body)
        elseif contact.state == ENDED then
            self:remove(body)
        end
        
        --[[
            if contact.state == BEGAN then
                print("Sensor BEGAN")
            elseif contact.state == MOVING then
                print("Sensor MOVING")
            else
                print("Sensor ENDED")
            end
        end
      ]]
    end
end