Modified ResampleSfx for a small speed gain

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@6075 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/snd_mem.c b/snd_mem.c
index 0eec602f9dbb478ef777ed1370d6b57dc8a48915..20d9c6b75f4d4900146540977766d4e87af1a991 100644 (file)
--- a/snd_mem.c
+++ b/snd_mem.c
@@ -33,7 +33,7 @@ ResampleSfx
 */
 size_t ResampleSfx (const unsigned char *in_data, size_t in_length, const snd_format_t* in_format, unsigned char *out_data, const char* sfxname)
 {
-       size_t srclength, outcount, i;
+       size_t srclength, outcount;
 
        srclength = in_length * in_format->channels;
        outcount = (double)in_length * shm->format.speed / in_format->speed;
@@ -46,6 +46,8 @@ size_t ResampleSfx (const unsigned char *in_data, size_t in_length, const snd_fo
        {
                if (in_format->width == 1)
                {
+                       size_t i;
+
                        for (i = 0; i < srclength; i++)
                                ((signed char*)out_data)[i] = in_data[i] - 128;
                }
@@ -80,61 +82,110 @@ size_t ResampleSfx (const unsigned char *in_data, size_t in_length, const snd_fo
                // also to be able to handle very long sounds.
                while (total_out < outcount)
                {
-                       size_t tmpcount;
+                       size_t tmpcount, i, j;
+                       unsigned int interpolation_limit, srcsample;
 
                        samplefrac = 0;
 
                        // If more than 1 sec of sound remains to be converted
                        if (outcount - total_out > shm->format.speed)
+                       {
                                tmpcount = shm->format.speed;
+                               interpolation_limit = tmpcount;  // all samples can be interpolated
+                       }
                        else
+                       {
                                tmpcount = outcount - total_out;
+                               interpolation_limit = ceil((double)(((remain_in / in_format->channels) - 1) << FRACTIONAL_BITS) / fracstep);
+                               if (interpolation_limit > tmpcount)
+                                       interpolation_limit = tmpcount;
+                       }
 
-                       // Convert up to 1 sec of sound
-                       for (i = 0; i < tmpcount; i++)
+                       // 16 bit samples
+                       if (in_format->width == 2)
                        {
-                               unsigned int j = 0;
-                               unsigned int srcsample = (samplefrac >> FRACTIONAL_BITS) * in_format->channels;
-                               int a, b;
+                               const short* in_ptr_short;
 
-                               // 16 bit samples
-                               if (in_format->width == 2)
+                               // Interpolated part
+                               for (i = 0; i < interpolation_limit; i++)
                                {
-                                       for (j = 0; j < in_format->channels; j++, srcsample++)
+                                       srcsample = (samplefrac >> FRACTIONAL_BITS) * in_format->channels;
+                                       in_ptr_short = &((const short*)in_ptr)[srcsample];
+
+                                       for (j = 0; j < in_format->channels; j++)
                                        {
-                                               // No value to interpolate with?
-                                               if (srcsample + in_format->channels < remain_in)
-                                               {
-                                                       a = ((const short*)in_ptr)[srcsample];
-                                                       b = ((const short*)in_ptr)[srcsample + in_format->channels];
-                                                       *((short*)out_ptr) = (((b - a) * (samplefrac & FRACTIONAL_MASK)) >> FRACTIONAL_BITS) + a;
-                                               }
-                                               else
-                                                       *((short*)out_ptr) = ((const short*)in_ptr)[srcsample];
+                                               int a, b;
 
+                                               a = *in_ptr_short;
+                                               b = *(in_ptr_short + in_format->channels);
+                                               *((short*)out_ptr) = (((b - a) * (samplefrac & FRACTIONAL_MASK)) >> FRACTIONAL_BITS) + a;
+
+                                               in_ptr_short++;
                                                out_ptr += sizeof (short);
                                        }
+
+                                       samplefrac += fracstep;
                                }
-                               // 8 bit samples
-                               else  // if (in_format->width == 1)
+
+                               // Non-interpolated part
+                               for (/* nothing */; i < tmpcount; i++)
                                {
-                                       for (j = 0; j < in_format->channels; j++, srcsample++)
+                                       srcsample = (samplefrac >> FRACTIONAL_BITS) * in_format->channels;
+                                       in_ptr_short = &((const short*)in_ptr)[srcsample];
+
+                                       for (j = 0; j < in_format->channels; j++)
                                        {
-                                               // No more value to interpolate with?
-                                               if (srcsample + in_format->channels < remain_in)
-                                               {
-                                                       a = ((const unsigned char*)in_ptr)[srcsample] - 128;
-                                                       b = ((const unsigned char*)in_ptr)[srcsample + in_format->channels] - 128;
-                                                       *((signed char*)out_ptr) = (((b - a) * (samplefrac & FRACTIONAL_MASK)) >> FRACTIONAL_BITS) + a;
-                                               }
-                                               else
-                                                       *((signed char*)out_ptr) = ((const unsigned char*)in_ptr)[srcsample] - 128;
+                                               *((short*)out_ptr) = *in_ptr_short;
+
+                                               in_ptr_short++;
+                                               out_ptr += sizeof (short);
+                                       }
 
+                                       samplefrac += fracstep;
+                               }
+                       }
+                       // 8 bit samples
+                       else  // if (in_format->width == 1)
+                       {
+                               const unsigned char* in_ptr_byte;
+
+                               // Convert up to 1 sec of sound
+                               for (i = 0; i < interpolation_limit; i++)
+                               {
+                                       srcsample = (samplefrac >> FRACTIONAL_BITS) * in_format->channels;
+                                       in_ptr_byte = &((const unsigned char*)in_ptr)[srcsample];
+
+                                       for (j = 0; j < in_format->channels; j++)
+                                       {
+                                               int a, b;
+
+                                               a = *in_ptr_byte - 128;
+                                               b = *(in_ptr_byte + in_format->channels) - 128;
+                                               *((signed char*)out_ptr) = (((b - a) * (samplefrac & FRACTIONAL_MASK)) >> FRACTIONAL_BITS) + a;
+
+                                               in_ptr_byte++;
                                                out_ptr += sizeof (signed char);
                                        }
+
+                                       samplefrac += fracstep;
                                }
 
-                               samplefrac += fracstep;
+                               // Non-interpolated part
+                               for (/* nothing */; i < tmpcount; i++)
+                               {
+                                       srcsample = (samplefrac >> FRACTIONAL_BITS) * in_format->channels;
+                                       in_ptr_byte = &((const unsigned char*)in_ptr)[srcsample];
+
+                                       for (j = 0; j < in_format->channels; j++)
+                                       {
+                                               *((signed char*)out_ptr) = *in_ptr_byte - 128;
+
+                                               in_ptr_byte++;
+                                               out_ptr += sizeof (signed char);
+                                       }
+
+                                       samplefrac += fracstep;
+                               }
                        }
 
                        // Update the counters and the buffer position