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In this tutorial should give you a basic idea how to use the particle system.
Step 1: Getting the tutorial resources
[tutorial7_resources.zip]
contains the particle sprite we are going to use in this tutorial.
Step 2: Extracting the tutorials resources
The tutorial resource package contains a folder called resources.
Copy and paste that folder to the folder where you have your
CorEngine Developmet Kit.
Step 3: Simple particle system
For this tutorials base init.lua, we will start with a simple
script that loads a level and runs the engine.
scene1 = Engine.LoadScene( "level1.pak" )
while ( Engine.Run() == true ) do
end
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All good so far. Now we will create a simple particle system.
scene1 = Engine.LoadScene( "level1.pak" )
particle1 = Create.Particles( "MyParticles", 1000 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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Try running the engine now. You should see some particles spawning above
the ground.
So what happened there? We created a particle system with the name
"MyParticles" and with the particle cap of 1000 particles. The
second argument of Create.Particles is the maximum amount of
particles which the particle system will allow to be created. The bigger
the value, the more memory it takes. You can later on change the value with
Particles.SetMaxCount if you want.
Next me set the position of the particle system, and finally we add the
particle system to the scene. Simple enough, isn't it?
Step 4: Texture, Color, Size
Next we will set a texture for the particles.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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Now you should see some round particles. Lets add some variable color next.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Particles.SetColorMin( particle1, 0.5, 0.5, 0.5, 1.0 )
Particles.SetColorMax( particle1, 1.0, 1.0, 1.0, 1.0 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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Nice, now we have some colored particles. Lets set a variable size next.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Particles.SetColorMin( particle1, 0.5, 0.5, 0.5, 1.0 )
Particles.SetColorMax( particle1, 1.0, 1.0, 1.0, 1.0 )
Particles.SetSize( particle1, 0.25, 1.0 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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You probably noticed that the size doesn't have two functions, one for
min and one for max. Instead the size has only one function which sets
both, the min and the max of the variable size.
Step 5: Velocity, Gravity, Spawn Delay
Lets say we wan't to make a fountain. First thing would be to set the
variable velocity to spread the particles upwards.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Particles.SetColorMin( particle1, 0.5, 0.5, 0.5, 1.0 )
Particles.SetColorMax( particle1, 1.0, 1.0, 1.0, 1.0 )
Particles.SetSize( particle1, 0.25, 1.0 )
Particles.SetVelocityMin( particle1, -3, -3, 1.0 )
Particles.SetVelocityMax( particle1, 3, 3, 7.0 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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Nice, now they are spreading upwards. Next we add some gravity to them.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Particles.SetColorMin( particle1, 0.5, 0.5, 0.5, 1.0 )
Particles.SetColorMax( particle1, 1.0, 1.0, 1.0, 1.0 )
Particles.SetSize( particle1, 0.25, 1.0 )
Particles.SetVelocityMin( particle1, -3, -3, 1.0 )
Particles.SetVelocityMax( particle1, 3, 3, 7.0 )
Particles.SetGravity( particle1, 0, 0, -20.0 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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Assuming that at this point, we wan't more particles, we just set the
spawn delay smaller. The amount of particles in existance at once can be
counted with life_span/spawn_delay. Lifespan can be set with
Particles.SetLifeSpan. Both the life span, spawn delay (and fade
speed) are set in seconds.
scene1 = Engine.LoadScene( "level1.pak" )
partex = Create.TextureFromFile( "ParticleTex", "resources/particle.png" )
particle1 = Create.Particles( "MyParticles", 1000 )
Particles.SetTexture( particle1, partex )
Particles.SetColorMin( particle1, 0.5, 0.5, 0.5, 1.0 )
Particles.SetColorMax( particle1, 1.0, 1.0, 1.0, 1.0 )
Particles.SetSize( particle1, 0.25, 1.0 )
Particles.SetVelocityMin( particle1, -3, -3, 1.0 )
Particles.SetVelocityMax( particle1, 3, 3, 7.0 )
Particles.SetGravity( particle1, 0, 0, -20.0 )
Particles.SetSpawnDelay( particle1, 0.01 )
Particles.SetLifeSpan( particle1, 1.5, 2.0 )
Actor.SetPosition( particle1, 0.0, 0.0, 3.0 )
Scene.AddParticles( scene1, particle1 )
while ( Engine.Run() == true ) do
end
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That should give you a REALLY shiny fountain...
In addition to the particle parameters introducet in this tutorial, there
are some more of them, like fade speed and variable position. Also you can
set a mesh for the particle system and the particles with be spawned
according to the vertices of the mesh. Check the API documentation for more
information.
Thats it! I hope you enjoyed the tutorial, and if you have any comments
about it, please post to the
forums.
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