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Comments:
<OliverKlo> Do any of you guys have advice on having 2d text/icons overlaying the scene?
<ZeZu> Stevie-O: just switch to orthographic projection and turn of depth buffering
<ZeZu> then render it to the screen like any 2d obj.
<Stevie-O> hmmk
<ZeZu> Anyone around that knows much about VBOs or something faster than vertex arrays, i'm getting really bad performance in some places and i dont know why
<Dr^Nick> Hrm. I know a bit :P again, I use d3d more now
<ZeZu> yea
<ZeZu> well
<androvsky> I know PBOs pretty well, but I don't know much about anything dealing with geometry
<ZeZu> for some reason i'm getting some pretty awfull slowdowns using vertex arrays
<ZeZu> I wonder if its all the state changes or the rendering
<ZeZu> b/c d3d is a lot faster
<ZeZu> and i copy the data twice with d3d
<ZeZu> I looked at VBOs for opengl once, trying to find more info on it now, but it looked like it only worked for indexed geometry
<androvsky> I think now that the PBO extension is out, you can put pretty much whatever you feel like in the buffer
<Dr^Nick> they work pretty much the same as regular vertex arrays
<Dr^Nick> except you put the data in the vbo first
<ZeZu> what is PBO ?
<ZeZu> maybe i'll kill setting the rendermode and see if its the state changes causing the slowdown
<ZeZu> i'm on a 7900GT and only getting like 10fps in some demos when my d3d gets 50
<ZeZu> its killing me ;|
<Kutulu> state changes are generally to be avoided when possible
<androvsky> PBO is basically a VBO, but you can put textures in it... fewer restrictions basically
<ZeZu> not possible to avoid them
<ZeZu> I write a vid plugin for an emulator
<Dr^Nick> ZeZu - put state changes in display lists
<ZeZu> yes i was thinking of that
<Dr^Nick> then call your DL to make the changes.
<ZeZu> on my radeon9800 i never had this problem
<Dr^Nick> but get rid of your vertex arrays and use vbos :p
<ZeZu> well
<androvsky> can you put a dynamic texture in a display list?
<ZeZu> vbos are just a cache or can i write directly into memory ?
<ZeZu> (vram)
<androvsky> you can sorta write into memory...
<Dr^Nick> ZeZu - you lock the data (get a memory ptr) and copy it over
<androvsky> it either winds up in what's called agp memory (for fast DMAs) or it winds up on the card
<ZeZu> so pretty much like vbuffer in d3d ?
<Dr^Nick> PBO's btw, are just an extension of the buffer interface to include pixel data
<Dr^Nick> so you don't want to use them "instead" of vbos
<ZeZu> i dont need pixel data i dont think, i load textures and get an id in the normal method
<ZeZu> then just cache them
<androvsky> oh, and getting a real pointer with a VBO (mapbuffer or whatever) is typically pretty slow... getting the pointer takes much more time than the memcpy
<androvsky> BufferSubData is much faster
<ZeZu> huh?
<androvsky> there's two ways of getting data into a VBO
<androvsky> one is you call a mapbuffer routine and it gives you a normal pointer that you can use with memcpy or whatever (even disk reads)
<androvsky> the other is to call BufferData and it uploads it for you, but you don't get a pointer to play with
<ZeZu> hmm
<androvsky> You have to call BufferData anyway to allocate the memory
<ZeZu> well i'll check them both out, see if i can just use bufferdata
<ZeZu> Is there somewhere better than just http://oss.sgi.com/projects/ogl-sample/registry/ARB/vertex_buffer_object.txt to get info on these ?
<androvsky> no, the oss.sgi.com examples are the best and sanest and easiest to understand that I've found, sadly
<ZeZu> ok
<ZeZu> thanks
<androvsky> out of curiosity, I've got a grand total of 16 textured quads... will immediate mode kill me, or do I need to switch over vertex arrays?
<Dr^Nick> you'll be fine
<androvsky> good... my texturing is kinda wonky
<androvsky> wasn't looking forward to figuring out how to make it work in any other way
<ZeZu> I hope this helps out, this data isn't getting stored and staying cached it will get replaced every frame
<ZeZu> so that means i need to delete all of the buffers each frame i'd imagine as well
<androvsky> no
<androvsky> you just call BufferSubData to replace what's changed
<Dr^Nick> zezu - you just tell them they're dynamic and sub the data
<ZeZu> ok
<androvsky> looks like all of my program's time is spent in BufferSubData
<androvsky> seriously starting to suspect a motherboard issue
<androvsky> speed test on our raid array runs at the same speed as a ramdisk :)
<JohnnyL> hi
<swppop> need help with push/pop matrix
<Maloeran> Ask away
<swppop> i;m drawing 6X6 lines to creat a "grid" can i paste code here?
<Maloeran> Use rafb.net/paste preferably
<swppop> whts rafb?
<Maloeran> Post there and give us the url
<Maloeran> It's commonly used to share code without flooding channels
<swppop> whats the full url?
<Maloeran> www.rafb.net/paste/
<swppop> ok sec
<swppop> there http://rafb.net/paste/results/BRxnYn97.html
<swppop> so i;m drawing the lines and after that i'm calling afunction that moves a QUADS but it clears the screen and i don't see the 'grid'
<swppop> so i thought to use push pop matrix one matrix for the 'grid' and anothere for the QUADS
<Maloeran> Are you drawing at a Z of 1.0 with a default modelview matrix when your near plane is at 0.1?
<swppop> allso if posible can you recomand me an opengl book?
<Maloeran> Topic, the redbook
<Maloeran> The paper version covers more, but the basics are the same
<Maloeran> at a Z of 0.0 I meant, with your glVertex2
<swppop> i use glVertex2 4 times to draw the lines each time diffreant values
<Maloeran> Ah there's a glTranslate. Execution flow isn't entirely clear with this Java thing :)
<swppop> where the glTranslate causes me the "lose" the grid?
<Maloeran> This code is seriously weird. Why call glClear() before rendering quad and after the grid? The Push/Pop is quite useless there
<swppop> i'm a bigginer...
<Maloeran> Your glClear() is clearing the color and depth buffers, so your grid disappears
<Maloeran> I recommend reading the Redbook and staying very far away from Nehe
<swppop> hehe ok what line is the wrong call for glClear
<Maloeran> Clear the buffers at the beginning of the frame, not after rendering the lines
<swppop> i'm trying amazon and ebay to find Redbook it seems there a lot of rebooks is the a more specifiec name?
<swppop> i've removed the glClear() but i got the same problem i had without this line the moveing qued is'n been cleared and i't all smeared when it moves
<swppop> leaveing it's trail
<Maloeran> Clear the buffers at the beginning of the frame
<swppop> i'm not sure where is it
<Maloeran> You really need to read the Redbook and understand the basics of opengl before poking around. These Nehe lessons have got everything wrong
<swppop> ok thanks do you know where can i get it at and dose it have a more specific name may be an aouther name?
<Maloeran> There's an url to an online version right in the topic
<swppop> thanks alot for all your help!
<Maloeran> The paper version covers more features regarding recent hardware, but you can learn the basics in any version
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