掉落弹跳：装备落地弹三下才安静

fx-lootbounce

local LootDrop = {}
local CONST = { GRAVITY = 500, ELASTIC = 0.4, MAX_BOUNCE = 3 }

function LootDrop.Spawn(x, y, itemID)
    local d = {
        x = x, y = y,
        vx = (math.random() - 0.5) * 200,
        vy = -180 - math.random() * 120,
        bounces = 0, itemID = itemID
    }
    table.insert(LootDrop._drops, d)
end

function LootDrop:Update(dt)
    for _, d in ipairs(self._drops) do
        if not d.rest then
            d.vy = d.vy + CONST.GRAVITY * dt
            d.x = d.x + d.vx * dt
            d.y = d.y + d.vy * dt
            d.vx = d.vx * 0.98
            if d.y >= GROUND_Y then
                d.y = GROUND_Y
                d.vy = -d.vy * CONST.ELASTIC
                d.bounces = d.bounces + 1
                if d.bounces >= CONST.MAX_BOUNCE or math.abs(d.vy) < 30 then
                    d.rest = true
                end
            end
        end
    end
end

return LootDrop