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Benchmark program for 3 diffrent alpha algorithms

alpha_test.c (text/plain), 5.56 KB, created by Mattias Karlsson on 2006-01-22 14:45:00 UTC

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Description:

Filename:

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Creator: Mattias Karlsson

Created: 2006-01-22 14:45:00 UTC

Size: 5.56 KB

patch

obsolete

>
>#include <sys/time.h>
>#include <stdio.h>
>
>#ifndef PIXELS
>#define PIXELS (256*256*256)
>#endif
>
>unsigned int src_buffer[PIXELS];
>unsigned int shift_buffer[PIXELS];
>unsigned int multishift_buffer[PIXELS];
>unsigned int div_buffer[PIXELS];
>
>void shift(void)
>{
>   unsigned int *src = src_buffer;
>   unsigned int *dest = shift_buffer;
>   unsigned int i;
>   for(i=0; i < PIXELS; i++)
>   {
>      // unpack pixels
>      unsigned int src_num = *src;
>      unsigned int rs = (src_num >> 24)&0xff;
>      unsigned int gs = (src_num >> 16)&0xff;
>      unsigned int bs = (src_num >> 8)&0xff;
>      unsigned int alpha = (src_num) & 0xff;
>
>      unsigned int dest_num = *dest;
>      unsigned int rd = (dest_num >> 24)&0xff;
>      unsigned int gd = (dest_num >> 16)&0xff;
>      unsigned int bd = (dest_num >> 8)&0xff;
>
>      // perform blend
>      rd += ((rs-rd)*alpha)>>8;
>      gd += ((gs-gd)*alpha)>>8;
>      bd += ((bs-bd)*alpha)>>8;
>
>      // pack pixel
>      dest_num = dest_num & 0xff;
>      dest_num |= (rd & 0xff) << 24;
>      dest_num |= (gd & 0xff) << 16;
>      dest_num |= (bd & 0xff) << 8;
>      *dest = dest_num;
>
>      dest++;
>      src++;
>   }
>}
>
>void multishift(void)
>{
>   unsigned int *src = src_buffer;
>   unsigned int *dest = multishift_buffer;
>   unsigned int i;
>   for(i=0; i < PIXELS; i++)
>   {
>      // unpack pixels
>      unsigned int src_num = *src;
>      unsigned int rs = (src_num >> 24)&0xff;
>      unsigned int gs = (src_num >> 16)&0xff;
>      unsigned int bs = (src_num >> 8)&0xff;
>      unsigned int alpha = (src_num) & 0xff;
>
>      unsigned int dest_num = *dest;
>      unsigned int rd = (dest_num >> 24)&0xff;
>      unsigned int gd = (dest_num >> 16)&0xff;
>      unsigned int bd = (dest_num >> 8)&0xff;
>
>      // perform blend
>      unsigned int premultR = (rs-rd)*alpha;
>      unsigned int premultG = (gs-gd)*alpha;
>      unsigned int premultB = (bs-bd)*alpha;
>      rd += (premultR>>8)+(alpha>>7)+(premultR>>16);
>      gd += (premultG>>8)+(alpha>>7)+(premultG>>16);
>      bd += (premultB>>8)+(alpha>>7)+(premultB>>16);
>      
>      // pack pixel
>      dest_num = dest_num & 0xff;
>      dest_num |= (rd & 0xff) << 24;
>      dest_num |= (gd & 0xff) << 16;
>      dest_num |= (bd & 0xff) << 8;
>      *dest = dest_num;
>
>      dest++;
>      src++;
>   }
>}
>
>void div(void)
>{
>   unsigned int *src = src_buffer;
>   unsigned int *dest = div_buffer;
>   unsigned int i;
>   for(i=0; i < PIXELS; i++)
>   {
>      // unpack pixels
>      unsigned int src_num = *src;
>      unsigned int rs = (src_num >> 24)&0xff;
>      unsigned int gs = (src_num >> 16)&0xff;
>      unsigned int bs = (src_num >> 8)&0xff;
>      unsigned int alpha = (src_num) & 0xff;
>
>      unsigned int dest_num = *dest;
>      unsigned int rd = (dest_num >> 24)&0xff;
>      unsigned int gd = (dest_num >> 16)&0xff;
>      unsigned int bd = (dest_num >> 8)&0xff;
>
>      // perform blend
>      rd = (255*rd + (rs-rd)*alpha)/255;
>      gd = (255*gd + (gs-gd)*alpha)/255;
>      bd = (255*bd + (bs-bd)*alpha)/255;
>
>      // pack pixel
>      dest_num = dest_num & 0xff;
>      dest_num |= (rd & 0xff) << 24;
>      dest_num |= (gd & 0xff) << 16;
>      dest_num |= (bd & 0xff) << 8;
>      *dest = dest_num;
>
>      dest++;
>      src++;
>   }
>}
>
>// calculate |a-b|
>unsigned int error(unsigned int a, unsigned int b)
>{
>   int err;
>
>   err = ((int)a) - ((int)b);
>
>   // caluclate |err|
>   if(err < 0)
>      err = -err;
>
>   return (unsigned int)err;
>}
>
>void accuracy(void)
>{
>   unsigned int src,alpha,dest;
>   unsigned int shift_sum=0;
>   unsigned int shift_cnt=0;
>   unsigned int multi_sum=0;
>   unsigned int multi_cnt=0;
>   
>   for(alpha=0; alpha < 256; alpha++)
>   {
>      for(src=0; src < 256; src++)
>      {
>	 for(dest=0; dest < 256; dest++)
>	 {
>	    unsigned int shift,multishift,div;
>	    unsigned int err;
>	    int temp;
>	    
>	    // calculate simple shift value
>	    shift = (dest + (((src-dest)*alpha)>>8))&0xff;
>
>	    // calculate multishift value
>	    temp = (src-dest)*alpha;
>	    multishift = (dest + ((temp>>8) + (alpha>>7) + (temp>>16)))&0xff;
>
>	    // calculate div value
>	    div = ((255*dest + (src-dest)*alpha)/255);
>
>	    // check error margins.
>
>	    err = error(shift,div);
>	    if(err != 0)
>	    {
>	       shift_sum += err;
>	       shift_cnt++;
>	    }
>	    
>	    err = error(multishift, div);
>	    if(err != 0)
>	    {
>	       multi_sum += err;
>	       multi_cnt++;
>	    }
>	 }
>      }
>   }
>
>   printf("shift_sum = %d\n", shift_sum);
>   printf("shift_cnt = %d\n", shift_cnt);
>   printf("multi_sum = %d\n", multi_sum);
>   printf("multi_cnt = %d\n", multi_cnt);
>}
>
>int main(int argc, char *argv[])
>{
>   struct timeval val;
>   double start,end;
>
>#ifndef NO_INIT
>   // unit arrays
>   unsigned int s,a,d,i;
>   for(i=0; i < PIXELS; i++)
>   {
>      s = (i % 256);
>      d = (i / 256)&0xff;
>      a = (i / (256*256))&0xff;
>	   
>      src_buffer[i] =
>	 (s)<<24 |
>	 (s)<<16 |
>	 (s)<<8  |
>	 (a)<<0;
>      shift_buffer[i] =
>	 (d)<<24 |
>	 (d)<<16 |
>	 (d)<<8  |
>	 (d)<<0;
>      multishift_buffer[i]=shift_buffer[i];
>      div_buffer[i]=shift_buffer[i];
>   }
>#endif
>   
>   // run speed tests
>   gettimeofday(&val, NULL);
>   start = val.tv_sec*1e6 + val.tv_usec;
>   shift();
>   gettimeofday(&val, NULL);
>   end = val.tv_sec*1e6 + val.tv_usec;
>   printf("Shift = %lg usec\n", end-start);
>
>   gettimeofday(&val, NULL);
>   start = val.tv_sec*1e6 + val.tv_usec;
>   multishift();
>   gettimeofday(&val, NULL);
>   end = val.tv_sec*1e6 + val.tv_usec;
>   printf("Multishift = %lg usec\n", end-start);
>   
>   gettimeofday(&val, NULL);
>   start = val.tv_sec*1e6 + val.tv_usec;
>   div();
>   gettimeofday(&val, NULL);
>   end = val.tv_sec*1e6 + val.tv_usec;
>   printf("Div = %lg usec\n", end-start);
>
>   // run accuracy test
>   accuracy();
>
>   return 0;
>}

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We are currently migrating Bugzilla to GitHub issues.Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.

We are currently migrating Bugzilla to GitHub issues.
Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.
When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.