Can't make applyForce do anything

Codea Craft
21

I found that even if I say body.awake = true, right before applying force, it still doesn’t move sometimes. Does awake get cleared when it thinks an object is still?

22

@RonJeffries I think the awake variable is read only. That’s used to check if the object is sleeping or awake. The sleepingAllowed variable is what gets set. Should set that variable to true then check the awake variable and see what it shows.

PS. I tried it and when I set sleepingAllowed to false, awake is false. If set to true, awake is true.

Add this to draw(), you can watch it change from true to false in a few seconds.

    if BoxBody.awake == false then
        text("awake is false",WIDTH/2,HEIGHT-50)
    else
        text("awake is true",WIDTH/2,HEIGHT-50)
    end
23

you’d think that sleepingAllowed = false would set awake = true.

Is it really backward?

I’ve seen awake change. Mostly it stays off even when the thing does respond. And nothing I do makes it respond every time. I think there’s a bug in there somewhere.

I guess awake could be just a status that is written but not read inside. If so, I’d like to know what I have to do to wake the thing up. Right now I’m afraid to document the force stuff because I can’t explain it.

24

This somewhat convoluted version uses sleepAllowed=false, which does seem to work backward. The force button applies an upward force on the next draw cycle. if you set force = n, it’ll apply force that many times, in the next n draw cycles.

The wake button sets the body.awake to true and force to 1. That usually results in the object waking up and moving. but not always.

the awake/asleep status is displayed near the bottom of the screen.

-- ApplyForce?

function setup()
    scene = craft.scene()
    --scene.physics.gravity = vec3(0,0,0)
    createFloor()
    createBox()
    scene.camera:add(OrbitViewer, vec3(0,0,0), 20, 1, 20)
    angle = 0
    parameter.action("Wake", wake)
    parameter.action("Force", applyForce)
    force = 0
end

function wake()
    BoxBody.awake = true
    force = 1
end

function applyForce()
    force = 1
end

function update(dt)
    scene:update(dt)
end

-- Called automatically by codea 
function draw()
    if force > 0 then
        print("force ", BoxBody.awake)
        --BoxBody.awake = true
        BoxBody:applyForce(vec3(00,400,00))
        force = force - 1
    end
    --print(scene.physics.paused)
    update(DeltaTime)
    scene:draw()    
    if BoxBody.awake then
        text("awake",300,100)
    else
        text("asleep", 300,100)
    end
end

function createBox()
    local box = scene:entity()
    local body = box:add(craft.rigidbody, DYNAMIC, 1) -- mass
    body.restitution = 0.8
    body.sleepingAllowed = true
    BoxBody = body
    box:add(craft.shape.box, vec3(1,1,1))
    box.model = craft. model.cube(vec3(1,1,1))
    box.material = craft.material(asset.builtin.Materials.Specular)
    box.material.map = readImage(asset.builtin.Blocks.Missing)
    return box
end

function createFloor()
    local floor = scene:entity()
    local body = floor:add(craft.rigidbody, STATIC)
    body.restitution = 0.9
    floor:add(craft.shape.box, vec3(25, 0.1, 25))
    floor.model = craft.model.cube(vec3(25, 0.1, 25))
    floor.y = -1.05
    floor.material = craft.material(asset.builtin.Materials.Specular)
    floor.material.map = readImage(asset.builtin.Blocks.Brick_Grey)
    floor.material.offsetRepeat = vec4(0,0,25,25)
    return floor
end