lua - Corona SDK 自定义物理体

Question

我对电晕中的自定义形状有一些麻烦。

这是我的代码，它的作用是我在场景中添加了一些球体，以便它们落入篮子内，这个篮子是我在 newBasket() 函数中定义的自定义形状对象，问题是篮子确实与地面物体碰撞，但不与球体碰撞，我不知道为什么，请在这里帮助我，我在其他地方找不到解决方案，提前致谢。

_W = display.contentWidth
_H = display.contentHeight

--Physics
local physics = require("physics")
physics.start()
physics.setDrawMode("debug")

-- iOS
display.setStatusBar(display.HiddenStatusBar)

-- screen boundaries
local ground = display.newRect(0, _H, _W, 5)
local leftWall = display.newRect(0,0,1,_H)
local rightWall = display.newRect(_W,0,1,_H)
physics.addBody(ground, "static", {friction = .2, bounce = .1})
physics.addBody(leftWall, "static", {friction = .2, bounce = .1})
physics.addBody(rightWall, "static", {friction = .2, bounce = .1})

local function newBasket()
    local body = display.newImage("assets/basket.png")
    body.x = 0 body.y = 0

    local physics_body = {}
    physics_body["basket"] = {
        {
            --LeftArm
            density = 10, friction = 10, bounce = 0.15, 
            shape = {-126, 40, -110, 40, -140, -64, -156, -64}

        },

        {
            --Bottom
            density = 10, friction = 1, bounce = 0, 
            shape = {-121, 60, 125, 60, 128, 40, -126, 40}

        },
        {
            --RightArm
            density = 10, friction = 10, bounce = 0.15, 
            shape = {113, 40, 129, 40, 158, -64, 143, -64}

        }

    }
    physics.addBody(body, unpack(physics_body["basket"]) )

    return body
end

local basket = newBasket()
basket.x = _W * .5 basket.y = _H - 100

local function newPlanet()

    local planets = {
        {img = "bigBall.png", radius = 45},
        {img = "mediumBall.png", radius = 30}, 
        {img = "smallBall.png", radius = 20}
    }

    local n = math.random(1,3)

    local img = "assets/" .. planets[n].img
    local ball = display.newImage(img)
    ball.x = math.random((_W * 0.5) -100, (_W * 0.5) + 100) ball.y = 0

    physics.addBody(ball, {bounce = 0.3, radius = planets[n].radius})
end

local function spawnPlanets(number)

    local function spawn(e)
        newPlanet()

        if(e.count == number) then
            timer.cancel(tmr)
            tmr = nil
        end
    end

    tmr = timer.performWithDelay(500, spawn, number)
end

spawnPlanets(20)

Answer 1

根据manual :

If a shape is specified, then the body boundaries will follow the polygon provided by the shape. Note that the maximum number of sides per shape is eight, and all angles must be convex. [...] The shape coordinates must be defined in clockwise order, and the resulting shape must be convex-only.

所以你有两个问题对你不利。首先，必须按顺时针顺序定义形状，就像我在下面的示例中所做的那样。其次，所有的形状都必须是凸面的(即使是复杂的体型)，所以你不能做任何像新月或篮子一样自行转动的东西。

不幸的是，这意味着您必须将篮子做成 3 个独立的形状。此外，由于它们现在是独立的形状，它们在掉落时不会粘在一起(除非您使用 joints )。我刚刚制作了篮子 3 个静态物体并将其放在正确的位置开始:

local function newBasket()
    local physics_body = {}
    physics_body["basket"] = {
        {
            --LeftArm
            density = 10, friction = 10, bounce = 0.15,
            shape = {-126, 40, -156, -64, -140, -64, -110, 40 }

        },

        {
            --Bottom
            density = 10, friction = 1, bounce = 0,
            shape = {-121, 60,-126, 40, 128, 40, 125, 60 }

        },
        {
            --RightArm
            density = 10, friction = 10, bounce = 0.15,
            shape = {113, 40, 143, -64, 158, -64, 129, 40 }

        }

    }
    for k,shape in pairs(physics_body["basket"]) do
        local body = display.newRect(0, 0, 200, 100)
        body.x = display.contentCenterX
        body.y = display.contentHeight - 60

        physics.addBody(body, 'static', shape )
    end
end

newBasket()