HUMP - yet another set of helpers

[vrld]

Minor tweak in hump.timer:

You can now stop the execution of periodic timers by returning false from the function, e.g.

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-- spawn a new enemy every 5 seconds or until the hive is destroyed
Timer.addPeriodic(5, function()
    if not hive or hive.life <= 0 then return false end
    hive:spawnZombieClown()
end)

[Gnx]

Minor tweak in hump.timer:

You can now stop the execution of periodic timers by returning false from the function, e.g.

Code: Select all

-- spawn a new enemy every 5 seconds or until the hive is destroyed
Timer.addPeriodic(5, function()
    if not hive or hive.life <= 0 then return false end
    hive:spawnZombieClown()
end)

Thats actually very useful

[Patooty]

Apologies if I missed it, but I wasn't able to find any talk on the camera module in this thread. Do you know of a working example somewhere? I'm having some problems getting it to work, and not sure if I'm just doing something stupid / overlooking something.

I'm able to create a camera object by doing like so:

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Vector = require 'library/hump/vector.lua'
Camera = require 'library/hump/camera.lua'

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mainCamera = Camera:new()

But when I try to call mainCamera:attach() I get the following error:

http://imgur.com/a5eOz


But if I instead initialize the camera like so:

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mainCamera = Camera:new(Vector(100,100), 2, math.pi/2)

then the error I get is:

http://imgur.com/fNhID


Edit: I had initially assumed that the vector was being incorrectly read as not-a-vector, but upon further investigation... In the camera class I decided to check why exactly the assert was failing:

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local typeStr = string.format("zoom is of type: %s", type(self.zoom))
	assert(type(self.zoom) == "number", typeStr)

yields:

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zoom is of type: table

It seems that the camera's fields are incorrect, though I'm still unsure what correct solution would be.

[tentus]

Have you seen the documentation at http://vrld.github.com/hump/#Camera?

[Patooty]

Yeah, my second attempt to initialize the camera actually came directly from that page. I have no other camera code besides initializing it (in an init function) and trying to attach/detach the camera (within a draw function). I feel like I'm having problems because of my inexperience with Lua. I don't see how the camera.zoom could be reporting that it's a table type. Here's the init function for the camera in camera.lua for easy reference:

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local function new(pos, zoom, rot)
	local pos  = pos or vector(love.graphics.getWidth(), love.graphics.getHeight()) / 2
	local zoom = zoom or 1
	local rot  = rot or 0
	return setmetatable({pos = pos, zoom = zoom, rot = rot}, camera)
end

[vrld]

You need to replace the ":" with a "."
The : is a lua shortcut to set the first function argument to the thing before colon, so this

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Camera:new(Vector(100,100), 2, math.pi/2)

is equivalent to:

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Camera.new(Camera, Vector(100,100), 2, math.pi/2)

Calling it like so will work:

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Camera.new(Vector(100,100), 2, math.pi/2)

Or use the preferred way:

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Camera(Vector(100,100), 2, math.pi/2)

You can see a working camera example here, especially in this file and in this file. Note that this uses an outdated hump version, where attach()/detach() were named predraw()/postdraw().

[Patooty]

Seems like I had a pretty warped understanding (or misunderstanding) of how the ':' worked.

Thanks very much for your help

[Nixola]

I didn't know it at all '

[MarekkPie]

The : operator is simply syntactic sugar.

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obj:foo(x)
-- is equivalent to
obj.foo(self, x)

So that can be a way of helping you understand when you use the . operator and when you use the : operator. If you haven't created an object of that classes type, then use the . operator, since you have no self yet. If you are operating on an already created object, then you use the : operator, so that you can use any variables stored within that object.

[kikito]

The : operator is simply syntactic sugar.

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obj:foo(x)
-- is equivalent to
obj.foo(self, x)

MarekkPie means this:

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obj:foo(x)
-- is equivalent to
obj.foo(obj, x)