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Posted 03 November 1999 - 10:03 PM
Posted 23 October 1999 - 11:31 AM
Posted 23 October 1999 - 12:09 PM
If you are blitting a lot to system memory there you really can't take advantage of any hardware acceleration because there is none.
If you want to do alpha-blending, or if you want to do color conversion, you will really have to write your own blitter.
DirectDraw's Blit locks the surface before and unlocks after. So if you have a lot of blits you have that Lock/Unlock overhead
Also, it's not hard to write your own blitter.
Posted 23 October 1999 - 12:23 PM
Posted 23 October 1999 - 05:40 PM
1- I guess I will learn something.
2- I am in the process of making an alpha blitter so might as well continue it
3- I guess eventually, I will have les problems porting.
Anyways, Splat i will continue writting my own blitter maybe you can help me optimize it later on!
Posted 23 October 1999 - 07:56 PM
Anyways i suggest you leave ddraw blitting as a option (after all if they have 32mb of memory and you can fit all your images in vram.......)
Posted 23 October 1999 - 08:49 PM
I agree that it would be stupid to forget the DirectDraw blitter, since those video memory -> video memory blits are just SO nice. Having a full-featured self-written software blitter, a damn-fast bare-bones DirectDraw software blitter, and a super-fast video-video mem hardware blitter gives you quite an arsenal when it comes to speeding up your game once you run into graphic bottlenecks.
Posted 24 October 1999 - 05:59 PM
And I quote:
"you can't beat the speed of hardware period. Use the blitter."
So bassicly I will use the DX blitters for basic blitting, but for doing alpha, and additive blending I will have to go and write my own stuff.
Posted 24 October 1999 - 06:20 PM
My project game is written purely with software draws to a system-memory buffer, which is blitted to the screen. This allows for very exchangable software drawing routines. (Have a draw pointer that can be set for normal, alpha, add, or whatever drawing style you wish)
Still, if you're going to be > 640x480 res, or doing alot of overdraw, hardware blit is a good idea, even if it makes you unportable.
Posted 24 October 1999 - 07:50 PM
Depending on your game, you can avoid tons of locks/unlocks if you do it yourself. Also, since you know what format the data will be in, your blitter can be very specialized and fast.
If you only have a couple of blits per frame to do, then go ahead and use the ddraw blitter, but if you have more than 10 or so, I'd start to consider writing your own.
Posted 27 October 1999 - 09:53 AM
ati in general i think is one of em who else?
Posted 28 October 1999 - 05:53 PM
Posted 02 November 1999 - 05:59 PM
however, no cards have support for advanced blitting functions such as alpha blending, add-blending, etc etc, which is why we're all making our own.
Posted 02 November 1999 - 08:00 PM
Posted 02 November 1999 - 09:15 PM
Posted 02 November 1999 - 11:57 PM
Stuff to remember:
-Some AGP cards can hardware blit to and from system and video memmory very very fast, some actually use system ram as video ram (watch your system ram drop by up to 16Megs). Example Intel's I740 very nice graphics card.
-Some PCI cards support DMA blitting to and from system ram but to take advantage of hardware acceleration lock the surface, some cards can get around this.
-As far as I know no ISA card supports hardware blitting with system ram.
Write 3 update/blitting routines
1. Takes advantage of AGP cards that support system to video ram blits.
2. Takes advantage of DMA blitting if the lock call is not required use the 1st routine.
3. Write your own blitting routine in ASM for system to video ram blits as that will be faster then Direct X software blits.
If anyone wants more details on how to check for these features contact me on
Stibbs - Multimedia Expert
Posted 03 November 1999 - 10:03 PM