Sprites 3D question...

lethalpolux · Post by **lethalpolux** » Thu Oct 16, 2003 1:21 pm

Another little thing:
why is it better to display all sprites 3D at the same time ( after Start3D(), display all sprites, Stop3D())..?
Is it more faster?
Because it's not evident to do that.
I want to know if it is valable to modify my code ( at the moment, i display my sprites 3D when i need them and i put start3D() and Stop3D() every time ).
Thanx

Codemonger · Post by **Codemonger** » Thu Oct 16, 2003 5:35 pm

It is faster to put the code between Start3D and Stop3D, because Directx would not have to make as many state changes and it can flush the sprites to the gpu all at once. But seeing as they are just 3d sprites and if you are running a fast Cpu you probably wouldn't notice a speed difference at all, unless you start to max out the number of sprites you are using, then you will notice a speed decrease. Anyway just my thoughts, all in all I wouldn't worry too much about it.

As far as organising your code it probably would be better and more efficient to have your sprites lumped together.

coma · Post by **coma** » Thu Oct 16, 2003 6:56 pm

I have made some tests :

Code: Select all

InitSprite() : InitKeyboard() : InitSprite3D() 
OpenScreen(800,600,16,"") 
  
CreateSprite (0,64,64,#PB_Sprite_Texture)
CreateSprite3D(0,0)
CreateSprite (1,64,64,0)

;draw a circle on each sprite
StartDrawing (SpriteOutput(0))
    FrontColor (128,0,0) :  Circle (32,32,32)
StopDrawing()
StartDrawing (SpriteOutput(1))
    FrontColor (0,0,128) :  Circle (32,32,32)
StopDrawing()

Repeat 
    ExamineKeyboard ()
    ClearScreen (0,0,0)

    ;FIRST LOOP
    timer =  TimeGetTime_()
    Start3D() 
    For i=0 To 5000
        DisplaySprite3D(0,320,240,255)
    Next
    Stop3D()
    For i=0 To 5000
        DisplayTransparentSprite (1,400,240)
    Next
    timer1 =  TimeGetTime_() - timer

    ;SECOND LOOP
    timer =  TimeGetTime_()
    For i=0 To 5000
        Start3D() 
            DisplaySprite3D(0,320,240, 255)
        Stop3D()
        DisplayTransparentSprite (1,400,240)
    Next
    timer2 =  TimeGetTime_() - timer

    StartDrawing(ScreenOutput())
        FrontColor (255,255,255) : DrawingMode (1)
        Locate (200,50) : DrawText ("loop 1 : "+Str(timer1)+" ms")
        Locate (200,65) : DrawText ("loop 2 : "+Str(timer2)+" ms")
    StopDrawing()
    FlipBuffers() 
Until KeyboardPushed(#PB_Key_Escape)

End

In the first loop, I draw 5000 3d sprites (start/stop3d outside the loop), then 5000 classic sprites.
In the second loop, the I draw alternately a 3d sprite and a classic sprite (start/stop3d inside the loop).

Something strange is that in 32 bit screen mode, the difference between the two loops decrease a lot (almost same time for both).

vanleth · Post by **vanleth** » Fri Oct 17, 2003 12:40 am

I get a "Error in line 24: Start3D() must be called before DisplaySprite3D()" in your test code

Think you need to have only one Start3D() and Stop3d() in you main flipbuffer() loop.

I do not know for sure, but my guess is that routines like Start3D() is optimized to work within a single flipbuffer() cycle. So using more Start3D() within a flipbuffer() cycle could give various results on different systems.

As for the speed difference in 16 bit mode vs. 32 bit I wouldn't be surprised performance would be better in 32 bit, since newer 3D cards often perfroms better in that mode.

Just my thoughts
Van

coma · Post by **coma** » Fri Oct 17, 2003 12:48 am

the code works perfectly here.....

You can use a lot of start3d/stop3d in your main loop, no problem.
And in a game, it's very usefull to put some 3d sprites behind the classic sprites (shadows...) and others 3d sprites in front (smoke, light...).

vanleth · Post by **vanleth** » Fri Oct 17, 2003 12:58 am

With debugger on, i only get around 4 cycles before the above Start3D() error halts the code.

Nvidia Geforece4 Mx440 (45.33 Driver), DirectX 9

coma · Post by **coma** » Fri Oct 17, 2003 1:04 am

strange... Probably a bug.
Are you using pb v3.80 ?

And if you remove the second loop ?

vanleth · Post by **vanleth** » Fri Oct 17, 2003 1:05 am

Yep using 3.8

vanleth · Post by **vanleth** » Fri Oct 17, 2003 1:12 am

Tested it abit more, and it seems that Escaping the test code with 'ESC' works very slow on my system. So in my restless mude, I've Alt-Tabbed out of the program to quickly and then i get the Start3D() error. Without beeing restless it works, but it takes 10 secs to quit the app and it dosn't display the "loop1" and "loop2" text.

It works better ,not perfect, with one loop only. Still i don't get any text info

coma · Post by **coma** » Fri Oct 17, 2003 1:21 am

ok :)

so, try to reduce the number of displayed sprites. 500 instead of 5000 in the loops for exemple.

vanleth · Post by **vanleth** » Fri Oct 17, 2003 1:25 am

if i remove all Start3d() stuff and what's inside it, the StartDrawing() info Text shows, else it won't.

And reducing the sprite numbers helps on Escaping out

lethalpolux · Post by **lethalpolux** » Fri Oct 17, 2003 8:18 am

Thanx codemonger,coma!
But it seems that sprites 3D works better when you use only one Start3D/Stop3D in code ( with GF4 MX it's sure! ).. I've made the tests with my Geforce 4TI4200 128Mo, no problem, but the same program with a GF4 MX 64Mo slow down about 10/20 fps...
Put only one start3D/Stop3D have reduced this difference(5/10)... and i put always sprite3D on sprite2D ( with a little modified code )

To solve the problem of the fps' decrease, i've deleted 5/6 sprites 3D... and the performance returns...

Post by **Fred** » Fri Oct 17, 2003 10:10 am

Yes, if possible use only one Start3D()/Stop3D per loop as it initialize the little 3D engine every time.

lethalpolux · Post by **lethalpolux** » Fri Oct 17, 2003 10:18 am

Thanx fred!

But, what is the limit of sprites 3D.. video card memory,chipset?
What make my code run faster on my GF4TI 128Mo than the same on a GF4MX 64Mo ( with same PIV and memory )..?
how to optimized ( if it's possible )?
I'm happy to see you again fred.

( LJ2 : 45% coded - if you want to test the beta... soon )