To summarize what you need is:

Change CC_CONTENT_SCALE_FACTOR calls to _CC_CONTENT_SCALE_FACTOR in CCParticleSystem.m

static inline CGFloat _CC_CONTENT_SCALE_FACTOR()
{
	if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
		return 2.0f;
	else
		return CC_CONTENT_SCALE_FACTOR();
}

Yep, I got it. The difference is that a normal particle drawn on the screen with GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA will cut out from the black background, whereas if that background was alpha = 0, then it wouldn't have anything to cut out of and would appear as only the coloured parts of the particle, missing all the black. You can see this in my screenshot.

The trick was to first grab this black by making a CCRenderTexture and drawing the particles on it with GL_SRC_ALPHA, GL_ZERO. This would leave just the background and remove all the alpha that the particles would take up. I made this a green texture with [rt1 beginWithClear:0 g:1 b:0 a:1]; just for fun, since it'll be used to get rid of the unused black and nothing else.

I then created another texture with [rt2 beginWithClear:0 g:0 b:0 a:0]; and drew the particles on it with the usual GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA of alpha blending.

Then I created my main texture with [rt beginWithClear:0 g:0 b:0 a:1] and drew this black texture onto it. I then drew the green one with GL_ZERO, GL_ONE_MINUS_SRC_ALPHA and I got the same result as usual.

However, I only did this because the reason behind it was bugging me. Now that I've figured that out, I can get back to making the effect I was after: an additive blend flame particle but without blending it into the background :)

Thanks a lot for your help!

No. When you render the particles, in normal blending, they blend with the underlaying image. If that image has alpha = 0, it will look different from an image with alpha = 1.
In additive blending, you just add the color + alpha of the particle system. This often causes particle systems like fire to "whiten out" because every pixel finally adds to full white, full opacity.

I sort of understand that the transparency is causing an issue, but don't I render the particles first and then add then onto a transparent surface? Wouldn't this leave the resulting texture the same as the one on the left?

I guess it is because you render particles on a surface with no alpha. I think, that if you changed particle blending to additive, that it would look more the same.
I am not sure how you can avoid that.

Even weirder than that, I can even add an Icon.png into the CCRenderTexture, and it looks fine:

So what else could cause the particle to be different when adding it to a texture :S

EDIT: reading a bit further into this, could it be a premultiplied alpha problem?

I had to use [child onEnter] to trigger the particle into rendering. I don't know why, since .active == YES. Also, I call [rt beginWithClear:0 g:0 b:0 a:0];. So I have a similar setup to what you've outlined and I've now got this:

Both are the same particle. The left one is a child of the layer. The right one is first drawn onto the CCRenderTexture and then this is added to a CCNode, which is added to the layer. For some reason, the right one differs. Both particles use the same blend function and I have also tried adding the same particle into the CCNode and it looks identically to the left particle. So something is not quite right with drawing the particle onto the CCRenderTexture. Would you have any idea what could cause it?

It isnt nearly as complicated as you think :)
The particle system will obey the coordinate system of the render texture. If you have a render texture of 100 * 100, setting the position of the particle system to 50, 50, will place it in the center.
You do not visit the render texture. To draw it, you simply add it as a child to ex your layer.
You do also not create the render texture each frame, or call visit inside a draw method. This is very bad for performance. In stead you create a single instance of the render texture, and place rendering in you scheduled frame tick.

Something like this

// init of class

rte = [ CCRenderTexture renderTextureWithWidth:200 height:300 ];
rte.position = RTE_POSITION;
[ self addChild: rte ]; 

// manually retain the particles as you dont add them to a container
particles = [ [ CCParticleSystemQuad particleWithFile:PARTICLE_FILE ] retain ];

And in update

-( void )update:( ccTime )dt {

  [ particles update:dt ];

  [ rte beginWithClear ];
  [ particles visit ];
  [ rte end ];

}

How would one go about adding a CCRenderTexture into a CCParticleSystem and draw the CCParticleSystem into the CCRenderTexture, then draw this texture instead of the CCParticleSystem. This will allow a blend function to be used between the CCParticleSystem and the CCRenderTexture. The reason being this:

http://gamedev.stackexchange.com/questions/22989/how-can-i-achieve-a-good-fire-effect-with-alpha-blending-and-particles/22990#22990

Here's what I have in the draw: of CCParticleSystem:

-(void) draw {
	CCRenderTexture *rte = [CCRenderTexture renderTextureWithWidth:200 height:300];
	[rte beginWithClear:0 g:0 b:0 a:0.5];
	[super draw];
	[rte end];
	[rte visit];
}

Whatever I'm doing is slightly wrong, because the CCParticleSystem texture drawn onto the CCRenderTexture is moving across the CCParticleSystem as the CCParticleSystem moves around. This is probably something to do with draw and how it works with positions. Is there a way to still do all this inside the CCParticleSystem (so I can still keep it all in one object), or do I have to make a second class to store both the CCRenderTexture and also the CCParticleSystem?

I found a Tutorial that teaches how to do this:

http://mobile.tutsplus.com/series/build-a-caterpillar-game-with-cocos2d/

Anyone have any suggestions for getting CoCos2d to do the button effects on the free amazing breaker game? I really like how when you hit the play button the particles flash across the screen but I am not exactly sure how to implement the effect. Thanks

Hi Everyone!

I am really excited to announce the release of Particle Alchemist! It's a particle system prototyping utility that persons can use to simulate and test particle system settings for their apps. You can save plists and access them in the iTunes File Sharing or send them to your email. You have 30 built-in particle system templates to start you off with. In addition, you can also open up existing plist files that you made from Particle Designer and change them to your liking, then create a new tweaked plist file. it is for the iPad only, though.

It is FREE to use! Please try it out and review it. Thanks!

Check it out at the App Store Link

To have a sprite behind another one, it must be added before. the draw are done in the "addchild" order, so first add, first display and the last are the top most.

you can create sprite, without "addchild" it and do all addchild at the end of the method, that way, you can manage who are on top and who are on bottom.

i think the best way for you to learn "game programming", is to buy some books, on cocos 2D programming or on "general" game programming.

@JC I need more help figuring out how to apply your method to my code above. The only thing I could think of (being so new to this), is to duplicate my code to create a "myBox1" to follow "myBox".

'CCSprite *myBox = [CCSprite node];
[myBox setTextureRect:CGRectMake(0, 20, 8, 8)];
[myBox setPosition:ccp(160, 340)];
[myBox setAnchorPoint:ccp(.5,10)];

[myBox setColor:ccGREEN];
[self addChild:myBox];

id rotate1 = [CCRotateBy actionWithDuration:0 angle:15];
id delay = [CCDelayTime actionWithDuration:.1];

[myBox runAction:[CCRepeatForever actionWithAction:[CCSequence actions:rotate1, delay, nil]]];

CCSprite *myBox1 = [CCSprite node];
[myBox1 setTextureRect:CGRectMake(0, 20, 8, 8)];
[myBox1 setPosition:ccp(160, 340)];
[myBox1 setAnchorPoint:ccp(.5,10)];

[myBox1 setColor:ccc3(0, 255, 255)];
[self addChild:myBox1];

id rotate2 = [CCRotateBy actionWithDuration:0 angle:15];
id delay2 = [CCDelayTime actionWithDuration:.1];

[myBox1 runAction:[CCRepeatForever actionWithAction:[CCSequence actions:rotate2, delay2, nil]]];'

Now how do I get it so "myBox1" is not on top of "myBox", but one step behind.

Having no background in programming, even this simple task is hard to figure out for me. Even though there are a lot of tutorials on YouTube, its hard to find one that discusses my specific situation. I have also been searching (without success) for a school nearby that teaches cocos2d. If I had a professor that could show me how to do the specific things I want to do, my progress would be much accelerated. I want to know, how others, like yourself, learned when you were just starting out. Any advice I can get, from more experienced programmers, is much appreciated.

Thank You.

whats even strange that the distribution copy played on an iPad is different also in the fact that the particle effects appear after a single death then are always there from then on, very strange

yep just tried release build and just like distribution build the particles show up occasionally sometimes yes some times no even when the same code to call them is used.

so i wonder what differs form debug mode on device and sim to release and distribution builds on sim and device.

no i did not i can do this but even if the results are the same as the distribution build i still have the same problem why does it happen, will try a release build in a few mins

ermm just curious did you test it in the simulator and on the device for release mode?

hi tone yes i will def consider perhaps a 2 hit or 3 hit rule that perhaps could be selected by setting game difficulty to easy to super easy,thus scores under these conditions would be entered on easy and super easy leader boards. will start coding and submit an update.

as far as menu animations go i know the screens sliding in and out all the time take time but i feel they are paramount to the look of the game but i will consider putting in an instant play button that takes you back to the last level you died on, how does that sound. thanks colyn

p.s just checking that you realise that you can slow the ship right down by pushing back on the joystick thus making the caves easy to navigate.

Yes, I really do like the game too.

May I make one suggestion? Can you have it so the player doesn't die right away if they bump the top of the Rock? Have some forgiveness for certain situations?

I like the end bosses!

On and another thing. The menu animations seem slow to me. I seem to get impatient waiting for them sometimes.

Hi tone thanks for your response no I did not relise this at all , now stupid do I feel right now, very strange it keeps crashing will investigate, do you see the problem I have about particles occur not every time I have n instance of the ship class.very strange.

Yes I'm very proud of the graphics , my favourite are the ice level and lava level which you won't have reached yet due to crashing.

Only trouble, have not accomplished very many downloads at all since release which is worrying since it took me A year to code.
I feel it's a good game with replay value with good graphics but just not getting any exposure.

Anyway back on topic if anybody could point in any way why particles are inconsistent I would be very great full .

Tone I tested on iPhone 3G and 3GS and iPhone 4 did not do any iPod testing so that might have been my problem like I say I will investigate.

Ok I finally saw the ship trail at the end of level 2 but the game crashed going into level three. I closed down everything like you said but it still crashed.

Also, you know that apps that are not in the foreground don't take up resources right?

http://speirs.org/blog/2012/1/2/misconceptions-about-ios-multitasking.html

Also I have to say the graphics are great. I really like the Rock level. Also the trail behind the ship looks cool.

Hi tone you might have to close down some apps if you have a lot running as it uses a lot of graphical memory. I tend to close all apps down and runs fine but will lag or jump if a lot of apps are open on your device.

Yes that's my problem there should be a particle affect out the back Of the ship. There is on device in debug mode and on sim and but not when app made for distribution.very strange.

Thing is on into the ship flys to planet the particles are fine.even stranger as ship is same class that's getting called in game scene.

Any ideas

I tried it out but I think you might have some other issues as well.

I am running in on a iPod 4th gen and it would lag a bit and when I got to level 02 it crashed on me.

Other than that I didn't see particle effects coming out the back of the ship. I thought there would be.

I just downloaded it and I will check it out.

hi guys i wonder if anybody can share some light on the particle problem i have.
heres how i load them.

CCParticleSystem* system4;
system4 = [ARCH_OPTIMAL_PARTICLE_SYSTEM particleWithFile:@"jetstream.plist"];
system4.autoRemoveOnFinish = YES;
system4.position = ccp(0,14);
[self addChild:system4];

now in my resources i have all the files jet stream.plist and .png for the particles. the png is named in the plist so no problem there.

whats happening is the particles work fine in simulator and device while in debug mode.
but the distribution copy that people down load from iTunes they only work in certain scenes so its really strange.
what gets even stranger is the first scene a particle gets called it works fine but then i call another scene with that same particle affect and it does not load but all the time it loads fine in debug mode in sim and device.

can anybody help.

p.s the particle effect in question is part of a spaceship class. an instance of this class gets created for different scenes

thanks in advance colyn

check out the game in question Cave Shooter 2

Hello,

This is a old thread and the code seems out of sync with the latest release of cocos2d-iphone. Does anybody know how to make this sharing/reusing of a ParticleSystem work with the "new" CCParticleSystemQuad class?

I really hope one of you wizards can help me here, I could really need some performance boost in my game particles.

Best regards and high hopes
Søren

"An array of sprites" and "snake games": Thank you, I did a search on both of these and lots of results came up. I am in the process of going through them, one by one, to learn how others are doing it.
"Merci Beaucoup!" : )

by serpy, i mean "Snake" (serpy is the french name...:)) like http://www.flash-games.fr/Snackes-3003.html

it's a similar behaviour of your's.

as Stephen Morris say, you can make "my sample" more generic using an array of sprites and some values to describe the fade out.

@Jellyfish There is nothing stopping you from adapting JC's code and applying it to an array of sprites. You can then adjust the number of sprites easily as well as derive a formula for applying the alpha and relevant positions.