Difference between revisions of "Tuto tiny-ecs demo Part 10 Conclusion"

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(Created page with "__TOC__ In this chapter we will make the player1 able to "shoot" and "hurt" enemies. This will be done in two parts: first enabling the player1 "shoot" action, then hurting...")
 
 
(3 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
__TOC__
 
__TOC__
  
−
In this chapter we will make the player1 able to "shoot" and "hurt" enemies.
+
So this is the last chapter.
  
−
This will be done in two parts: first enabling the player1 "shoot" action, then hurting the enemies with some fx and make them "die".
+
== Adding Buildings ==
 +
Let's finish the '''tiny-ecs demo''' by adding some buildings to our level1.
  
−
== Player1 can Shoot ==
+
In the entities folder "_E", let's add a file called "''eBuilding.lua''" for example.
−
We implement player1 can shoot in the '''SDynamicBodies''' system.
 
  
−
Please go to the "''sDynamicBodies.lua''" file to add some code.
+
This is the code for an '''EBuilding''' entity:
 
<syntaxhighlight lang="lua">
 
<syntaxhighlight lang="lua">
−
SDynamicBodies = Core.class()
+
EBuilding = Core.class()
  
−
function SDynamicBodies:init(xtiny, xnmes) -- tiny function
+
function EBuilding:init(xspritelayer, x, y, w, h)
−
self.tiny = xtiny -- ref so we can remove entities from tiny system
+
-- sprite
−
self.tiny.processingSystem(self) -- called once on init and every update
+
self.spritelayer = xspritelayer
−
self.nmes = xnmes -- a list of nmes we can hurt
+
self.sprite = Pixel.new(math.random(0xffffff), 1, w, h)
 +
self.sprite:setAnchorPoint(0.5, 1)
 +
-- params
 +
self.x = x
 +
self.y = y
 
end
 
end
−
-- ...
 
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
In the '''init''' function we add the list of enemies to the function signature and we make that list available to the other functions.
+
The only thing here is to change the anchor point of the '''EBuilding''' entity.
  
−
Then in the '''process''' function, we check if the player presses the ''action1'' button (the spacebar) and we set a random enemy in the '''nmes''' list to be hurt.
+
Now in the "''LevelX.lua''" file we add some buildings to tiny-ecs world:
 
<syntaxhighlight lang="lua">
 
<syntaxhighlight lang="lua">
−
function SDynamicBodies:process(ent, dt) -- tiny function
 
 
-- ...
 
-- ...
−
-- actions (player1)
+
-- tiny-ecs
−
if ent.isplayer1 and ent.isaction1 then
+
if self.tiny == nil then
−
ent.isaction1 = false
+
self.tiny = require "classes/tiny-ecs"
−
if #self.nmes > 0 then -- check nmes list is not empty
 
−
self.nmes[math.random(#self.nmes)].isdirty = true
 
−
else -- nmes list is empty
 
−
print("you killed everybody!")
 
−
end
 
 
end
 
end
−
-- move
+
self.tiny.tworld = self.tiny.world()
−
ent.x += ent.body.vx * dt
+
-- some deco (xspritelayer, x, y, w, h)
−
ent.sprite:setPosition(ent.x, ent.y)
+
for i = 1, 8 do -- 8 random buildings
−
end
+
self.tiny.tworld:addEntity(
 +
EBuilding.new(self.camera,
 +
math.random(myappwidth), 14*16,
 +
math.random(4*16, myappwidth/4), math.random(8, 12)*16
 +
)
 +
)
 +
end
 +
-- some enemies (xspritelayer, x, y, dx, dy)
 +
local nmes = {}
 +
for i = 1, 10 do -- we create 10 enemies
 +
-- ...
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
I set the ''hurt'' behavior as being the flag ''isdirty'' (some of my Box2D leftovers).
+
We add 8 randomly positionned and sized EBuilding entities.
−
 
 
−
So every time the player presses the spacebar, a random enemy from the nmes list will get hurt.
 
−
 
 
−
== Enemies can die ==
 
−
In order to hurt an enemy we need to add a new System. The system will decrease an enemy ''health'' which will eventually "die".
 
−
 
 
−
In the systems folder "_S", create a file called "''sNme1.lua''" for example, and copy the following code:
 
−
<syntaxhighlight lang="lua">
 
−
SNme1 = Core.class()
 
−
 
 
−
function SNme1:init(xtiny, xnmes) -- tiny function
 
−
self.tiny = xtiny -- ref so we can remove entities from tiny system
 
−
self.tiny.processingSystem(self) -- called once on init and every update
 
−
self.nmes = xnmes
 
−
end
 
−
 
 
−
function SNme1:filter(ent) -- tiny function
 
−
return ent.isnme
 
−
end
 
−
 
 
−
function SNme1:onAdd(ent) -- tiny function
 
−
end
 
−
 
 
−
function SNme1:onRemove(ent) -- tiny function
 
−
print("SNme1:onRemove")
 
−
end
 
−
 
 
−
function SNme1:process(ent, dt) -- tiny function
 
−
for i = #self.nmes, 1, -1 do -- scan in reverse
 
−
if self.nmes[i].isdirty then -- hit
 
−
self.nmes[i].health -= 1
 
−
self.nmes[i].washurt = 5 -- timer for a flash effect
 
−
self.nmes[i].sprite:setColorTransform(2, 0, 0, 3) -- the flash effect (a bright red color)
 
−
self.nmes[i].isdirty = false
 
−
if self.nmes[i].health <= 0 then -- dead :-(
 
−
self.tiny.tworld:removeEntity(self.nmes[i]) -- sprite removed from sprite layer in SDrawable
 
−
self.nmes[i] = nil -- remove from table
 
−
table.remove(self.nmes, i) -- remove from table
 
−
end
 
−
end
 
−
end
 
−
end
 
−
</syntaxhighlight>
 
  
−
In this system, when an entity is dirty (hurt), we decrease its health, set a timer for a flashing effect and if it dies, we remove it from tiny-ecs world and the '''nmes''' list.
+
'''I hope you like the demo'''!
  
−
Please note the sprite is removed from the sprite layer in the '''SDrawable''' system:
+
== Gideros Project ==
−
<syntaxhighlight lang="lua">
+
In the project I added an '''SDebugDraw''' system.
−
function SDrawable:onRemove(ent) -- tiny function
 
−
ent.spritelayer:removeChild(ent.sprite)
 
−
end
 
−
</syntaxhighlight>
 
  
−
Let's add the flashing effect to the '''SDynamicBodies''' system like so:
+
'''[[Media:tiny-ecs_demo.zip]]''' '''(tip: right click and save link as)'''
−
<syntaxhighlight lang="lua">
 
−
function SDynamicBodies:process(ent, dt) -- tiny function
 
−
-- hurt fx
 
−
if ent.washurt and ent.washurt > 0 then
 
−
ent.washurt -= 1
 
−
if ent.washurt <= 0 then
 
−
ent.sprite:setColorTransform(1, 1, 1, 1)
 
−
end
 
−
end
 
−
-- movement
 
−
if ent.isleft and not ent.isright then -- LEFT
 
−
ent.body.vx = -ent.body.speed
 
−
elseif ent.isright and not ent.isleft then -- RIGHT
 
−
ent.body.vx = ent.body.speed
 
−
-- ...
 
−
</syntaxhighlight>
 
  
−
If an entity counter ''washurt'' is greater than 0, we decrease it. When the counter reaches zero we set the entity sprite color back to normal.
+
== Conclusion ==
 +
This was my take on using '''tiny-ecs'''. To sum up:
 +
* tiny-ecs has a world
 +
* a world is made of entities and systems
 +
* entities have ids
 +
* entities can have components
 +
* components can serve as ids
 +
* a system filters the entities to act upon based on entities ids
 +
* a system can run once or every update
  
−
== Action ==
+
'''I really enjoy making games using the ECS paradigm. I hope to have given you the keys to experiment with it'''!
−
To see the result of our work, we need to add the '''SNme1''' system to tiny-ecs world.
 
  
−
In the "''levelX.lua''" file add the '''SNme1''' system:
 
−
<syntaxhighlight lang="lua">
 
−
-- ...
 
−
-- add systems to tiny-ecs
 
−
self.tiny.tworld:add(
 
−
SDrawable.new(self.tiny),
 
−
SDynamicBodies.new(self.tiny, nmes), -- add the nmes list here too!
 
−
SPlayer1Control.new(self.tiny),
 
−
SAI.new(self.tiny),
 
−
SNme1.new(self.tiny, nmes)
 
−
)
 
−
-- ...
 
−
</syntaxhighlight>
 
  
−
'''Remember we changed the ''SDynamicBodies'' init function signature, so you need to add the new parameter to the System here too'''!
+
'''Thanks for reading'''!
  
−
That's it!
+
== Further reading ==
 +
One last link if you want to know more about ECS:
  
−
'''You can run the demo and press the spacebar. A random enemy should get hit and eventually die, until you kill everyone'''.
+
'''[https://github.com/SanderMertens/ecs-faq#what-is-ecs github SanderMertens what is ecs]'''
  
  

Latest revision as of 15:29, 22 December 2023

So this is the last chapter.

Adding Buildings

Let's finish the tiny-ecs demo by adding some buildings to our level1.

In the entities folder "_E", let's add a file called "eBuilding.lua" for example.

This is the code for an EBuilding entity: 

EBuilding = Core.class()

function EBuilding:init(xspritelayer, x, y, w, h)
	-- sprite
	self.spritelayer = xspritelayer
	self.sprite = Pixel.new(math.random(0xffffff), 1, w, h)
	self.sprite:setAnchorPoint(0.5, 1)
	-- params
	self.x = x
	self.y = y
end

The only thing here is to change the anchor point of the EBuilding entity.

Now in the "LevelX.lua" file we add some buildings to tiny-ecs world: 

	-- ...
	-- tiny-ecs
	if self.tiny == nil then
		self.tiny = require "classes/tiny-ecs"
	end
	self.tiny.tworld = self.tiny.world()
	-- some deco (xspritelayer, x, y, w, h)
	for i = 1, 8 do -- 8 random buildings
		self.tiny.tworld:addEntity(
			EBuilding.new(self.camera,
				math.random(myappwidth), 14*16,
				math.random(4*16, myappwidth/4), math.random(8, 12)*16
			)
		)
	end
	-- some enemies (xspritelayer, x, y, dx, dy)
	local nmes = {}
	for i = 1, 10 do -- we create 10 enemies
	-- ...

We add 8 randomly positionned and sized EBuilding entities.

I hope you like the demo!

Gideros Project

In the project I added an SDebugDraw system.

Media:tiny-ecs_demo.zip (tip: right click and save link as)

Conclusion

This was my take on using tiny-ecs. To sum up:

  • tiny-ecs has a world
  • a world is made of entities and systems
  • entities have ids
  • entities can have components
  • components can serve as ids
  • a system filters the entities to act upon based on entities ids
  • a system can run once or every update

I really enjoy making games using the ECS paradigm. I hope to have given you the keys to experiment with it!


Thanks for reading!

Further reading

One last link if you want to know more about ECS:

github SanderMertens what is ecs


Prev.: Tuto tiny-ecs demo Part 9 Player Shoots Enemies Die
END


Tutorial - tiny-ecs demo

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