I have a problem: I wanted to implement some alphablending-effects in my 2d-game. So I''ve programmed some functions to create a lookup-table that is really fast (my opinion). I''ve also created a structure named "Alphabitmap" that holds the numbers of the alphablend-table (extracted from a bitmap). Look at the "firework-demo" of DirectX SDK (6.1) to see which effects I want to reach. My problem is the performance. The program only reaches 4fps when blending fullscreen (on an Athlon500 !) with this function: (I''m using Visual C++ 5 and DirectDraw) ---------------------------------------------- //16bit-565 USHORT b1=Alphabitmap->b; //get color USHORT g1=Alphabitmap->g; USHORT r1=Alphabitmap->r; USHORT b2; //colors on screen USHORT g2; USHORT r2; USHORT*dest_ptr = dest_buffer+(x+y*lpitch); //pointer to backbuffer (destination) USHORT dest_ptr_end=dest_buffer+((x+Alphabitmap->width)+y*lpitch); int *table_ptr = Alphabitmap->alpha; //pointer to alphatable USHORT dest =*dest_ptr; int table =*table_ptr; int loopend=(Alphabitmap->width*Alphabitmap->height); for(index=0; index>11; g2=(dest & 0x7E0)>>6; r2= dest & 0x1F; //tlut is the Alphablend-Lookup-Table: dest = ( tlut[table].color[b1][b2] | tlut[table].color[g1][g2]<<6 | tlut[table].color[r1][r2]<<11 ); *dest_ptr=dest; if(dest_ptr == dest_ptr_end) { dest_ptr+=(lpitch-Alphabitmap->width); dest_ptr_end+=lpitch; } //advance pointers dest_ptr++; table_ptr++; dest=*dest_ptr; //this seems to be the slowest operation in the loop (why??) table=*dab_aptr; } ---------------------------------------------- Have you an idea how this could be faster ??

cyberben, I was wondering if you had a website or anything where we can see some of your work?!?! You seem to be only saying, I know ASM, I know ASM, but haven''t showed us anything to prove your knowledge... well? it''s about time you do so... maybe you do have knowledge, but please.. show us.. dont just say i did that in ASM, and i did this... in 100% pure ASM.. wow... it seems impossible....

The only thing I hear in your posts is this:

"I could be very wrong though, I''m speaking mostly from what I''ve heard, so look around a bit more.."

I''ve tried the MMX enhanced code.
It''s really fast but the effect isn''t that
good as I wanted it to be...but there''s no choice.

There''s already a thing I can''t understand:
why does this take so much time:
dest=*dest_ptr; //(dest_ptr is the backbuffer)
I mean it''s only getting the value of where
the backbuffer-pointer points.
If I clear this operation I get 20fps or more.

And I don''t think that the lookup table in this code
causes cache thrashing, because it''s only 20*32*32 USHORTS.

But still thanks cyberben.