Platformer example [using bump]

rrraptor · January 2018

Just want to share a simple platformer example

Code is not very well commented, because my english is not good enough

https://github.com/MultiPain/gideros-platformer

SinisterSoft · January 2018

Nice example.

pie · January 2018

Cool, does it use bump? I see there is bump.lua in the file list but I am on mobile right now. Bump is native since some gideros release ago

I think you can remove that file and use the plugin. also, adding bump word in this topic will make it easier to find it later

rrraptor · January 2018

SinisterSoft said:
Nice example.

Thanks.

pie said:
Cool, does it use bump?

Yeah, it is.

pie said:
Bump is native since some gideros release ago

Hmm...i missed that...

pie said:
adding bump word in this topic will make it easier to find it later

Done

Edit: have some problems with native bump. I need custom response function for one-way platforms, and it looks like this:

local slide, cross = bump.responses.slide, bump.responses.cross
local oneWay = function(world, col, x, y, w, h, goalX, goalY, filter)
	if col.normal.y < 0 and not col.overlaps then
		col.didTouch = true
		return slide(world, col, x, y, w, h, goalX, goalY, filter)
	else
		return cross(world, col, x, y, w, h, goalX, goalY, filter)
	end
end
 
self.world:addResponse("oneWay", oneWay)

But with native bump, i cant get access to cross and slide function.

jdbc · January 2018

Thanks, I was thinking about to develop a platform game and I need to create some prototype first. You save me some time.

antix · January 2018

Nice one @rrraptor, I really like your solution to the one way platform issue

Maybe @hgy29 can build this one into cBump

hgy29 · January 2018

Yes, I certainly can add your custom response to native bump, One way platforms are so common with platformers that even original bump should have included it at first. i would call it platform instead of oneway though.

totebo · January 2018

Just to say, love the way you've coded the movement. So easy. May use the good bits in my next game.

rrraptor · January 2018

@hgy29 well, this is not my implementation) I found the solution on love2d forum. But kikito (bump dev) says:

for moving one-way platforms, you will need a bit more (platforms will need to "push up" whatever is touching them when they are moving up)

So the solution is a bit more complicated.

totebo · January 2018

I downloaded the demo from Github and tried to run it with the latest Gideros 2018.1.1. Got an error:

./Stuff/bump.lua:43: x must be a number, but was nil(a nil)
stack traceback:
	./Stuff/bump.lua:43: in function 'assertType'
	./Stuff/bump.lua:54: in function 'assertIsRect'
	./Stuff/bump.lua:617: in function 'add'
	Stuff/Platformer.lua:10: in function 'init'
	[string "property.lua"]:52: in function '__new'
	[string "property.lua"]:46: in function '__new'
	[string "property.lua"]:59: in function 'new'
	Scenes/GameScene.lua:68: in function 'loadLevel'
	Scenes/GameScene.lua:15: in function 'init'
	[string "property.lua"]:52: in function '__new'
	[string "property.lua"]:59: in function 'new'
	main.lua:8: in main chunk

I tried to require "cbump" instead of the Lua Bump, and then I get this error:

Scenes/GameScene.lua:43: attempt to index field 'responses' (a nil value)
stack traceback:
	Scenes/GameScene.lua:43: in function 'setupWorld'
	Scenes/GameScene.lua:12: in function 'init'
	[string "property.lua"]:52: in function '__new'
	[string "property.lua"]:59: in function 'new'
	main.lua:8: in main chunk

Would be great to get it working out of the box, to show people new to Gideros.

rrraptor · January 2018

@totebo i fixed that already )) Order matters...
See the commit
https://github.com/MultiPain/gideros-platformer/commit/bf41948f59196a8f5790614cbeb4d0342cee2511
or screenshot:

It doesn't work with native bump, for some reason. I removed custom response function, fixed "Item ray must be added to the world before getting its rect" error, and now player just crushing...

totebo · January 2018

Ok cool, halfway there! I also got that "item needs to be added" with Bump in my own game. Maybe it's a bug in the Gideros c version of Bump?

totebo · January 2018

@rrraptor The reason I wanted to download the demo was to see if jump height can be controlled. As in, the longer you hold jump the higher you jump.

rrraptor · January 2018

totebo said:
jMaybe it's a bug in the Gideros c version of Bump?

Yeah, in my case world:project(...) works in lua version without adding item to the world, but cbump requiring to do so.

totebo said:
jump height can be controlled

Nope, it doesnt.

Btw, this example will not work with native verion, becouse of custom response function.

hgy29 · January 2018

rrraptor said:

So the solution is a bit more complicated.

Sure, I used a custom filter instead for Arthur and additional game logic for moving platforms. But collision response would be a start anyway.

antix · January 2018

I didn't use any custom response for one way platforms, I just processed it in the collision filter.

MoKaLux · November 2022

rrraptor said:

totebo said:
jMaybe it's a bug in the Gideros c version of Bump?
Yeah, in my case world:project(...) works in lua version without adding item to the world, but cbump requiring to do so.
Btw, this example will not work with native verion, because of custom response function.

I think I would need this "custom response function" ability

I implemented moving platforms, that works great on horizontal moving platforms but not if they move vertically

rrraptor · November 2022

MoKaLux said:
I think I would need this "custom response function" ability I implemented moving platforms, that works great on horizontal moving platforms but not if they move vertically

Technically it is possible (using luaL_ref/luaL_unref), but requires alot of changes.

MoKaLux · November 2022

(at) rrraptor bump.lua you are using (which I have included in my test platformer) and gideros cbump are not behaving the same at all

I have two sample cases:
- bump.lua, when I am on a vertical moving platform I can jump when the platform is either going up or down which is super cool

- gideros cbump, when I am on a vertical moving platform I can only jump when the platform is going down

- bump.lua collisionfilter doesn't work as expected, that is the last elseif statement is always executed even if it doesn't collide at all

- gideros cbump collisionfilter works as expected

It is a shame because I would need a mix of bump.lua and cbump

I am investigating and trying to find where guderos cbump and bump.lua differ. I will also try to make a sample project to show exactly what I mean.

Here is my collisionfilter function (pass through platforms work out of the box without custom collisions)

self.collisionfilter = function(item, other)
	-- "touch", "cross", "slide", "bounce"
	if item.isplayer1 then
		if other.isnme then return "bounce" -- NOT TESTED
		elseif other.isground then return "slide" -- TESTS OK
		elseif other.isladder then return "cross" -- TESTS OK
		elseif other.isptpf then -- TESTS OK
			if item.isdown then return "cross" end -- go down on key down pressed
			if item.body.vy > 0 then -- going down
				local itembottom = item.y + item.h
				local otherbottom = other.y + 8 -- treshold magik XXX +2
				if itembottom <= otherbottom then return "slide" end
			end
		elseif other.ismvpf then  -- TEST OK WITH BUMP.LUA
			if item.body.vy > 0 then -- going down
				local itembottom = item.y + item.h
				local otherbottom = other.y + 8 -- treshold magik XXX
				if itembottom <= otherbottom then return "slide" end
			else
				return "cross"
			end
		elseif other.isspring then -- TESTS OK WITH GIDEROS CBUMP
			if item.body.vy >= 0 then -- going down
				print("xxx", item.body.vy) -- IN BUMP.LUA THIS CODE IS ALWAYS EXECUTED!!!
				return "bounce"
			end
		end
	end
end

PEACE

MoKaLux · November 2022

I thought I found it

!
bump.lua

function World:check(item, goalX, goalY, filter)
	filter = filter or defaultFilter
 
	local visited = {[item] = true}
--	local visitedFilter = function(itm, other) -- TYPO itm?
	local visitedFilter = function(item, other)
		if visited[other] then return false end
--		return filter(itm, other) -- TYPO itm?
		return filter(item, other)
	end
...
end

but no

to be continued

MoKaLux · November 2022

cbump Gideros is not the same as bump.lua

I don't know how to fix

but with Gideros there is always a way

MoKaLux · November 2022

rrraptor said:
Just want to share a simple platformer example
Code is not very well commented, because my english is not good enough

https://github.com/MultiPain/gideros-platformer

following Mister rrraptor's path I am proposing my bump (cbump) platformer

Let me share with you a screenshot, github should follow soon God's willing

I will also post on itch.io to see how it behaves and hopefully have some of you guys feedback

Viva Gideros Studio c++ luau

PS: sorry I couldn't work on c++ Qt lately (I hate them

)

MoKaLux · November 2022

first html5 test https://mokatunprod.itch.io/gideros-tests

E1e5en · December 2022

I am very interested in the ECS template and I have tried to use it and plan to do more. But I can't always decide for myself how correctly to break everything, how small. Here is an example of my splitting into character management systems (made on a different engine and with its own ECS implementation library).

Here I have divided each state into a separate system, the movement is also divided into systems for acceleration, braking and movement. I proceeded from the rule: divide everything. On using a separate system for the state, I read here: https://www.richardlord.net/blog/ecs/finite-state-machines-with-ash.html .
As a result, there are a lot of small pieces and it's probably better to combine some pieces anyway. Otherwise, it becomes difficult to control such a quantity.

MoKaLux · December 2022

@E1e5en I am new to ECS, I have examined rrraptor's ECS project https://github.com/MultiPain/Gideros-tiny-ECS, I watched many videos explaining ECS plus read some articles about it. The way I do it right now:
- entities have unique id
- entities can have components
- systems act on components (thus entities)

Will try to post my take on ECS asap

I don't use state machine yet because it seems I don't need it so far and that would complicate my code?!

E1e5en · December 2022

There is nothing complicated in the template itself. This can be called functional programming, where independent functions (installed in a certain sequence) simply change data (components), depending on other data (components). And the systems (functions) that relate to the engine simply use data from the components and api of the engine. The very essence is simple, but a good organization of these components and the system is a headache.
Therefore, it will be interesting to look at your solution. And the right decision will come only with experience, you need to practice using this template more.

E1e5en · December 2022

MoKaLux said:

I don't use state machine yet because it seems I don't need it so far and that would complicate my code?!

Perhaps it will not complicate it, but simply increase it. More precisely, it will increase the number of files/systems.

MoKaLux · December 2022

E1e5en said:
There is nothing complicated but a good organization of these components and the system is a headache.
And the right decision will come only with experience

That is exactly right, I try to find the right balance between all these myself and it much depends really on the type of project you have.
Right now I am implementing the shooting part and I am figuring out whether to create an entity, a component and a system for it or none at all

MoKaLux · December 2022

new html5 test https://mokatunprod.itch.io/gideros-tests
GH https://github.com/mokalux/PLATFORMER_CBUMP_TECS_20221101_wodt

Please note: this is still WIP, my code may not please everybody

, I tried to make it easy to "decrypt"

should be working:
- jump run walk shoot
- nmes platforms
- animations

not implemented:
- sounds
- other type of nmes
- the code can be simplified (merging the AIs)
- no score, no player die
- no optimisations
- no delta time

- no, no, no ...

Let's see how far I can take it, I will create a new thread to not spam rrraptor's mailbox

E1e5en · December 2022

MoKaLux said:
new html5 test https://mokatunprod.itch.io/gideros-tests
GH https://github.com/mokalux/PLATFORMER_CBUMP_TECS_20221101_wodt

It's funny that on a moving platform he can only walk, not run. I understand that it was done on purpose, an interesting decision.

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