Major slowdown creating more than 600 particles.
BlitzMax Forums/BlitzMax Beginners Area/Major slowdown creating more than 600 particles.
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| I'm getting severe slowdown when I create more than 600 individual stars for my games starfield. I have a very fast system and I remember doing the same in B3D and it not have a problem with it. So, I'm guessing that its my create_stars function. Here are da codeeeez: Below is the type for the stars : Global num_stars = 0 Global max_stars = 50 Global invaderlist:TList = CreateList() Global starlist:TList = CreateList() Type star Field xpos:Int Field ypos:Int Field speed:Int Function create_star() For Local x:Int = 0 To max_stars Local s:star = New star ListAddLast starlist,(s) s.xpos = rnd(0,GR_WIDTH) s.ypos = -1 s.speed = Rand(2,15) num_stars:+1 If num_stars > max_stars Exit EndIf Next End Function Function update_stars() For Local s:star = EachIn starlist s.ypos:+s.speed Next End Function Function draw_star() For Local s:star = EachIn starlist DrawImage stars,s.xpos,s.ypos,0 Next End Function Method remove_star() For Local s:star = EachIn starlist If s.ypos > GR_HEIGHT ListRemove starlist,(s) num_stars:-1 EndIf Next End Method End Type Is this efficiant enough? I was thinking that instead of deleting a star when it exits the screen borders to actually reuse it and change its y position to the top of the screen again. Would that be better than creating a new star each time? to help you guys more in helping me here is all the code. |
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| So, I'm guessing that its my create_stars function. Likewise, all the other functions seem to be fine. Replace with:
Function create_star()
For Local x:Int = 0 To (max_stars - num_stars)
Local s:star = New star
ListAddLast starlist,(s)
s.xpos = rnd(0,GR_WIDTH)
s.ypos = -1
s.speed = Rand(2,15)
num_stars:+1
Next
End Function
deleting a star when it exits the screen borders Stick to that method. Ryan |
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| Hmm! I tried it your way Ryan and I get the same slowdown. Theres no difference in speed. If I leave max_stars at 50 I get top speeds but the more I make the slower it gets. I've managed to get ok speeds by setting max_stars to 300 but anything above that kills the show. The thing is I remember reading somewhere that people have made particle systems with B3D which are capable of handling thousands of individual particles yet BlitzMax cant handle over 300. So, its either BlitzMax or the way I have coded this. |
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| Some particle handling suggestions - 1. Reduce the size of your particles 2. Make them move off screen as fast as possible 3. Give particles a life span, so that they can still disappear before going off-screen, so your stars could fade out, for example. 4. Do you really need hundreds of particles? Gotta go now, night night. Ryan |
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| Those are good tips, but doing any of those things now would be just burying your head in the sand. Its best to find the source of the slowdown and fix that. |
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| I took that type above and tested stars only. 15000 Stars a 24*24*16 and no noticeable slowdown. 6600GT, 2 GHz Sometime decent OpenGL Drivers arent part of the normal driver package and you have to install them separately. Without them, things get slow. Dont know how ATI handle this... |
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In your main loop, shouldn'tFor Local s:star = EachIn starlist s.remove_star() Next Simply be:
star.remove_star()
? |
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| Is this efficiant enough? I was thinking that instead of deleting a star when it exits the screen borders to actually reuse it and change its y position to the top of the screen again. Would that be better than creating a new star each time? Yes. Creating an Object is very expensive compared to reusing an existing one. I have star code that uses DrawRect and I can do 10,000 stars in about 4.9ms. That is A LOT of time (and way too many stars :-). You figure at 60FPS, you have approximately 16.67ms to do EVERYTHING. Taking up 25+% of the time drawing stars is bad. (1000ms/60FPS = 16.67ms per Frame) I use 100 stars for my game, which looks just fine and that drawing time is something along the lines of less than 0.5ms which is plenty fast for my needs (right now). You should create your stars outside of your main loop and don't destory them unless it's absolutely necessary (or it is not noticble to the user). I would also recommend taking a more OOP approach and create a Star Object with Methods rather then what you have here. If you're not sure how to do that, I can post some code for you later. |
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| Man, just for a starfield you really don't need all that `Type` stuff, just use an array so that you can be sure the memory used is sequential and it should be a lot faster. You don't need a linked list to generate a starfield. |
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| I think one of the problems is drawimage itself or the way it is working: It always recreates the quad with the texture from scratch instead of using the already existing quad and just reposition it. I get around 12000-15000 particles with my particle system (first it should become a port of a B3D one, but droped that idea and restarted to use the BM posibilities and 2D only optimations) until it breaks which is "crap" compared with around 30000 with Blitz3D and more stuff going on. I'm on a radeon 9700 with quite good drivers. |
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| Hi Guys. Thanks for the replies. I've changed the code so that it recycles each particle and resets its position to -1 when it goes beyond the boundaries of the screen. I've noticed a slight increase in speed but still lagging with just 401 particles. I have taken out the create_star() function and moved it outside the loop so it can only ever create 401 particles. I still get lag with this. Here is the current code for the stars and the code for the whole game: Global invaderlist:TList = CreateList() Global starlist:TList = CreateList() Type star Field xpos:Int Field ypos:Int Field speed:Int Function create_star() For Local x:Int = 0 To max_stars Local s:star = New star ListAddLast starlist,(s) s.xpos = rnd(0,GR_WIDTH) s.ypos = Rand(-1,-GR_HEIGHT) s.speed = Rand(2,15) num_stars:+1 Next End Function Function update_stars() For Local s:star = EachIn starlist s.ypos:+s.speed Next End Function Function draw_star() For Local s:star = EachIn starlist DrawImage stars,s.xpos,s.ypos,0 Next End Function Method recycle_star() For Local s:star = EachIn starlist If s.ypos > GR_HEIGHT s.ypos = -1 EndIf Next End Method End Type Now dreamora mentioned that it may be drawimage which is causing the problem so I'll try a simple pixel plot instead. I'll post the code in just a sec. :) [edit]Plot didnt make a single bit of difference. :/ |
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| I think the only real problem is the constraints of hardware I'm afraid - it's difficult getting a lot of action on the screen to move smoothly, especially in 3D. Would it be possible to create an animation instead of using particles? Do you really need hundreds of particles? Ryan |
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| Well i dont really need all those particles; its just that with B3D when I did the same it handled them with style. There may be a possibility of my OpenGL drivers not being up to scratch. I'll look in to that in a bit. Thanks for the help anyway fellas. :) |
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| Amon - You are moving in the right direction, but there are still some problems. To whoever recommended making sure u have the most up to date OGL drivers - I agree. Made a massive difference on my old PC. Avoid creating stuff and deleting it each loop - again as someone else said. If you have say falling raindrops and u delete them each time they hit the bottom of the screen and create a new one at the top, this will probs not kill your speed but it is better to recycle. Originally you were recreating and destroying your whole type list each loop which is BAD - but that problem is solved. In your main loop you have a sub loop over all invaders and do an invader.draw(), but invader.draw() loops over all the invaders inside itself - so if you have 3 invaders, you'll draw each of them 3 times! (I think). Try taking the loop out of the drawinvader function (and any others like this). There are further optimisations you can make - let's prove MAX can kick B3Ds ***. |
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| In your main loop you have a sub loop over all invaders and do an invader.draw(), but invader.draw() loops over all the invaders inside itself - so if you have 3 invaders, you'll draw each of them 3 times! (I think). Hi Falken. I did some tests and it definately doesn't draw the aliens 3 times. To be absolutely sur I removed the draw method and changed it to a function. This didnt help with the framerate. I guess it has to be my opengl drivers. Thanks for your help and suggestions. I guess I'll try to reduce the number of particles and assign them each a life span to reduce how long they are on screen. Thanks again :) |
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| I found your problem. You were calling the recycle method for each star, but there's also a loop for each star in the method. So for 400 stars you were doing 120000 interations! I do also think your aliens are also suffering from a similar situation. Just put a call to the recycle method inside the loop in the update function and remove it from your main loop. Here's the changes I made: [code] Strict 'image made global within type: slight speed increase 'star list global within type: very lisght speed increase Const GR_WIDTH = 1024, GR_HEIGHT = 768, DEPTH = 16, HERTZ = 60 Graphics GR_WIDTH,GR_HEIGHT,DEPTH,HERTZ SetMaskColor 255,0,255 Type star Field xpos:Int Field ypos:Int Field speed:Int Global starImg:TImage Global starlist:TList Global num_stars Global max_stars Function create_star() num_stars = 0 max_stars = 500 starlist=CreateList() For Local x:Int = 0 To max_stars-1 Local s:star = New star ListAddLast starlist,(s) s.xpos = rnd(0,GR_WIDTH) s.ypos = Rand(-1,-GR_HEIGHT) s.speed = Rand(2,15) num_stars:+1 Next 'create star image SetColor 255,0,255 DrawRect(0,0,3,3) SetColor 255,255,255 Plot 1,0 Plot 0,1 Plot 1,1 Plot 2,1 Plot 1,2 starImg=CreateImage(3,3) GrabImage(starImg,0,0) End Function Function update_stars() For Local s:star = EachIn starlist s.ypos:+s.speed s.recycle_star() s.draw_star() Next End Function Method draw_star() DrawImage starImg,xpos,ypos,0 End Method Method recycle_star() If ypos > GR_HEIGHT Then ypos = -1 End Method End Type Const TARGET:Int=60 Local frames:Int=0 star.create_star() Local frameTime:Int Local totalTime:Int=0 Local tCounter:Int=0 Repeat frameTime=MilliSecs() Cls SetColor 255,255,255 star.update_stars() DrawRect 0,0,160,28 SetColor 0,0,0 DrawText TARGET+" Frames:"+totalTime+"ms",0,12 DrawText "Stars:"+star.num_stars,0,0 tCounter:+(MilliSecs()-frameTime) If frames=TARGET Then totalTime=tCounter frames=0 tCounter=0 Else frames:+1 EndIf FlushMem Flip Until KeyHit(KEY_ESCAPE) |
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| It's probably a slow graphics card combined with the overhead of OpenGL, then. |
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| Hi Cajun17. Below you have xpos and ypos but I dont see them declared anywhere. Method draw_star() DrawImage starImg,xpos,ypos,0 End Method Method recycle_star() If ypos > GR_HEIGHT Then ypos = -1 End Method You "drawimage starimg,xpos,ypos" but I dont where xpos and ypos came about. If its to store the positions shouldnt it be s.xpos and s.ypos? I'm confused :/ |
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| No they shouldn't as they are declared in the type itself (the first 2 field declarations) and in methods you can access them without any need for self.xxx or similar. |
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| Ahh, I see. Thanks for that Dreamora. Well, I have altered my code accordingly and its running at top speeds. I have also learnt a lot more about OOP programming because of this thread. Thanks again all :) |
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| so how many particles does it take now to see a slow down ?? |
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| I could get 45k particles every frame at 60 FPS (3400+ AMD 1Gig DDR 9700 ATI 128MB). |
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| I can get 42.000 particles/frame at 60FPS (Athlon 2800+, ATI 9600Pro) Slightly less than that if I move the mouse. |
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| Is that all?! Looks like that code could do with some more work Amon! Ryan |
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| Well I tested it and and 60fps theres no slowdown with over 9000 particles. I pushed it up to 50,000 and got a slight lag for a split second when they were created but then it ran at top speeds. This is just with my code. I'm sure with more optimized code you can easily push 70-80,000 particles. The problem is I'm never going to need 80,000 particles. :/ |
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| Oh I was joking Amon! Ryan |
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| If you set the graphics driver to buffered Direct X first you should be able to push way more particles. I used buffered Direct X and could push 225,000 particles. SetGraphicsDriver BufferedD3D7Max2DDriver() This is on Dual 3.2Ghz Intel - ATI9700Pro 128MB |
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| What is this buffered mode? Are there drawbacks? Why isn't it used normally? And is there something equivalent for OpenGL? |
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| No, there is no equivalent for OpenGL |
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