Example #1
0
void
gegl_buffer_iterator_stop (GeglBufferIterator *iter)
{
  int index;
  GeglBufferIteratorPriv *priv = iter->priv;
  priv->state = GeglIteratorState_Invalid;

  for (index = 0; index < priv->num_buffers; index++)
    {
      SubIterState *sub = &priv->sub_iter[index];

      if (sub->current_tile_mode != GeglIteratorTileMode_Empty)
        release_tile (iter, index);

      if (sub->linear_tile)
        {
          if (sub->access_mode & GEGL_ACCESS_WRITE)
            gegl_tile_unlock (sub->linear_tile);
          gegl_tile_unref (sub->linear_tile);
        }

      gegl_buffer_unlock (sub->buffer);

      if (sub->access_mode & GEGL_ACCESS_WRITE)
        gegl_buffer_emit_changed_signal (sub->buffer, &sub->full_rect);
    }

  g_slice_free (GeglBufferIteratorPriv, iter->priv);
  g_slice_free (GeglBufferIterator, iter);
}
void
gegl_buffer_iterator_stop (GeglBufferIterator *iterator)
{
  GeglBufferIterators *i = (gpointer)iterator;
  gint no;
  for (no=0; no<i->iterators;no++)
    {
      gint j;
      gboolean found = FALSE;
      for (j=0; j<no; j++)
        if (i->buffer[no]==i->buffer[j])
          {
            found = TRUE;
            break;
          }
      if (!found)
        gegl_buffer_unlock (i->buffer[no]);
    }

  for (no=0; no<i->iterators; no++)
    {
      if (i->buf[no])
        iterator_buf_pool_release (i->buf[no]);
      i->buf[no]=NULL;
      g_object_unref (i->buffer[no]);
    }
#if DEBUG_DIRECT
  g_print ("%f %f\n", (100.0*direct_read/(in_direct_read+direct_read)),
                           100.0*direct_write/(in_direct_write+direct_write));
#endif
  i->is_finished = TRUE;
  g_slice_free (GeglBufferIterators, i);
}
gboolean
gegl_buffer_cl_iterator_next (GeglBufferClIterator *iterator, gboolean *err)
{
  GeglBufferClIterators *i = (gpointer)iterator;
  gboolean result = FALSE;
  gint no, j;
  cl_int cl_err = 0;

  if (i->is_finished)
    g_error ("%s called on finished buffer iterator", G_STRFUNC);
  if (i->iteration_no == 0)
    {
      for (no=0; no<i->iterators;no++)
        {
          if (i->buffer[no])
            {
              gint j;
              gboolean found = FALSE;
              for (j=0; j<no; j++)
                if (i->buffer[no]==i->buffer[j])
                  {
                    found = TRUE;
                    break;
                  }
              if (!found)
                gegl_buffer_lock (i->buffer[no]);

              if (i->flags[no] == GEGL_CL_BUFFER_WRITE
                  || (i->flags[no] == GEGL_CL_BUFFER_READ
                      && (i->area[no][0] > 0 || i->area[no][1] > 0 || i->area[no][2] > 0 || i->area[no][3] > 0)))
                {
                  gegl_buffer_cl_cache_flush (i->buffer[no], &i->rect[no]);
                }
            }
        }
    }
  else
    {
      /* complete pending write work */
      for (no=0; no<i->iterators;no++)
        {
          if (i->flags[no] == GEGL_CL_BUFFER_WRITE)
            {
              /* Wait Processing */
              cl_err = gegl_clEnqueueBarrier(gegl_cl_get_command_queue());
              if (cl_err != CL_SUCCESS) CL_ERROR;

              /* color conversion in the GPU (output) */
              if (i->conv[no] == GEGL_CL_COLOR_CONVERT)
                for (j=0; j < i->n; j++)
                  {
                    cl_err = gegl_cl_color_conv (i->tex_op[no][j], i->tex_buf[no][j], i->size[no][j],
                                                 i->format[no], i->buffer[no]->soft_format);
                    if (cl_err == FALSE) CL_ERROR;
                  }

              /* Wait Processing */
              cl_err = gegl_clEnqueueBarrier(gegl_cl_get_command_queue());
              if (cl_err != CL_SUCCESS) CL_ERROR;

              /* GPU -> CPU */
              for (j=0; j < i->n; j++)
                {
                  gpointer data;

                  /* tile-ize */
                  if (i->conv[no] == GEGL_CL_COLOR_NOT_SUPPORTED)
                    {
                      data = gegl_clEnqueueMapBuffer(gegl_cl_get_command_queue(), i->tex_op[no][j], CL_TRUE,
                                                     CL_MAP_READ,
                                                     0, i->size[no][j] * i->op_cl_format_size [no],
                                                     0, NULL, NULL, &cl_err);
                      if (cl_err != CL_SUCCESS) CL_ERROR;

                      /* color conversion using BABL */
                      gegl_buffer_set (i->buffer[no], &i->roi[no][j], 0, i->format[no], data, GEGL_AUTO_ROWSTRIDE);

                      cl_err = gegl_clEnqueueUnmapMemObject (gegl_cl_get_command_queue(), i->tex_op[no][j], data,
                                                             0, NULL, NULL);
                      if (cl_err != CL_SUCCESS) CL_ERROR;
                    }
                  else
#ifdef OPENCL_USE_CACHE
                    {
                      gegl_buffer_cl_cache_new (i->buffer[no], &i->roi[no][j], i->tex_buf[no][j]);
                      /* don't release this texture */
                      i->tex_buf[no][j] = NULL;
                    }
#else
                    {
                      data = gegl_clEnqueueMapBuffer(gegl_cl_get_command_queue(), i->tex_buf[no][j], CL_TRUE,
                                                     CL_MAP_READ,
                                                     0, i->size[no][j] * i->buf_cl_format_size [no],
                                                     0, NULL, NULL, &cl_err);
                      if (cl_err != CL_SUCCESS) CL_ERROR;

                      /* color conversion using BABL */
                      gegl_buffer_set (i->buffer[no], &i->roi[no][j], i->format[no], data, GEGL_AUTO_ROWSTRIDE);

                      cl_err = gegl_clEnqueueUnmapMemObject (gegl_cl_get_command_queue(), i->tex_buf[no][j], data,
                                                             0, NULL, NULL);
                      if (cl_err != CL_SUCCESS) CL_ERROR;
                    }
#endif
                }
            }
        }

      /* Run! */
      cl_err = gegl_clFinish(gegl_cl_get_command_queue());
      if (cl_err != CL_SUCCESS) CL_ERROR;

      for (no=0; no < i->iterators; no++)
        for (j=0; j < i->n; j++)
          {
            if (i->tex_buf_from_cache [no][j])
              {
                gboolean ok = gegl_buffer_cl_cache_release (i->tex_buf[no][j]);
                g_assert (ok);
              }

            if (i->tex_buf[no][j] && !i->tex_buf_from_cache [no][j])
              gegl_clReleaseMemObject (i->tex_buf[no][j]);

            if (i->tex_op [no][j])
              gegl_clReleaseMemObject (i->tex_op [no][j]);

            i->tex    [no][j] = NULL;
            i->tex_buf[no][j] = NULL;
            i->tex_op [no][j] = NULL;
          }
    }

  g_assert (i->iterators > 0);
  result = (i->roi_no >= i->rois)? FALSE : TRUE;

  i->n = MIN(GEGL_CL_NTEX, i->rois - i->roi_no);

  /* then we iterate all */
  for (no=0; no<i->iterators;no++)
    {
      for (j = 0; j < i->n; j++)
        {
          GeglRectangle r = {i->rect[no].x + i->roi_all[i->roi_no+j].x - i->area[no][0],
                             i->rect[no].y + i->roi_all[i->roi_no+j].y - i->area[no][2],
                             i->roi_all[i->roi_no+j].width             + i->area[no][0] + i->area[no][1],
                             i->roi_all[i->roi_no+j].height            + i->area[no][2] + i->area[no][3]};
          i->roi [no][j] = r;
          i->size[no][j] = r.width * r.height;
        }

      if (i->flags[no] == GEGL_CL_BUFFER_READ)
        {
          for (j=0; j < i->n; j++)
            {
              gpointer data;

              /* un-tile */
              switch (i->conv[no])
                {
                  case GEGL_CL_COLOR_NOT_SUPPORTED:

                    {
                    gegl_buffer_cl_cache_flush (i->buffer[no], &i->roi[no][j]);

                    g_assert (i->tex_op[no][j] == NULL);
                    i->tex_op[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                            CL_MEM_ALLOC_HOST_PTR | CL_MEM_READ_ONLY,
                                                            i->size[no][j] * i->op_cl_format_size [no],
                                                            NULL, &cl_err);
                    if (cl_err != CL_SUCCESS) CL_ERROR;

                    /* pre-pinned memory */
                    data = gegl_clEnqueueMapBuffer(gegl_cl_get_command_queue(), i->tex_op[no][j], CL_TRUE,
                                                   CL_MAP_WRITE,
                                                   0, i->size[no][j] * i->op_cl_format_size [no],
                                                   0, NULL, NULL, &cl_err);
                    if (cl_err != CL_SUCCESS) CL_ERROR;

                    /* color conversion using BABL */
                    gegl_buffer_get (i->buffer[no], &i->roi[no][j], 1.0, i->format[no], data, GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

                    cl_err = gegl_clEnqueueUnmapMemObject (gegl_cl_get_command_queue(), i->tex_op[no][j], data,
                                                               0, NULL, NULL);
                    if (cl_err != CL_SUCCESS) CL_ERROR;

                    i->tex[no][j] = i->tex_op[no][j];

                    break;
                    }

                  case GEGL_CL_COLOR_EQUAL:

                    {
                    i->tex_buf[no][j] = gegl_buffer_cl_cache_get (i->buffer[no], &i->roi[no][j]);

                    if (i->tex_buf[no][j])
                      i->tex_buf_from_cache [no][j] = TRUE; /* don't free texture from cache */
                    else
                      {
                        gegl_buffer_cl_cache_flush (i->buffer[no], &i->roi[no][j]);

                        g_assert (i->tex_buf[no][j] == NULL);
                        i->tex_buf[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                                 CL_MEM_ALLOC_HOST_PTR | CL_MEM_READ_ONLY,
                                                                 i->size[no][j] * i->buf_cl_format_size [no],
                                                                 NULL, &cl_err);
                        if (cl_err != CL_SUCCESS) CL_ERROR;

                        /* pre-pinned memory */
                        data = gegl_clEnqueueMapBuffer(gegl_cl_get_command_queue(), i->tex_buf[no][j], CL_TRUE,
                                                       CL_MAP_WRITE,
                                                       0, i->size[no][j] * i->buf_cl_format_size [no],
                                                       0, NULL, NULL, &cl_err);
                        if (cl_err != CL_SUCCESS) CL_ERROR;

                        /* color conversion will be performed in the GPU later */
                        gegl_buffer_cl_worker_transf (i->buffer[no], data, i->buf_cl_format_size [no], i->roi[no][j], FALSE);

                        cl_err = gegl_clEnqueueUnmapMemObject (gegl_cl_get_command_queue(), i->tex_buf[no][j], data,
                                                               0, NULL, NULL);
                        if (cl_err != CL_SUCCESS) CL_ERROR;
                      }

                    i->tex[no][j] = i->tex_buf[no][j];

                    break;
                    }

                  case GEGL_CL_COLOR_CONVERT:

                    {
                    i->tex_buf[no][j] = gegl_buffer_cl_cache_get (i->buffer[no], &i->roi[no][j]);

                    if (i->tex_buf[no][j])
                      i->tex_buf_from_cache [no][j] = TRUE; /* don't free texture from cache */
                    else
                      {
                        gegl_buffer_cl_cache_flush (i->buffer[no], &i->roi[no][j]);

                        g_assert (i->tex_buf[no][j] == NULL);
                        i->tex_buf[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                                 CL_MEM_ALLOC_HOST_PTR | CL_MEM_READ_ONLY,
                                                                 i->size[no][j] * i->buf_cl_format_size [no],
                                                                 NULL, &cl_err);
                        if (cl_err != CL_SUCCESS) CL_ERROR;

                        /* pre-pinned memory */
                        data = gegl_clEnqueueMapBuffer(gegl_cl_get_command_queue(), i->tex_buf[no][j], CL_TRUE,
                                                       CL_MAP_WRITE,
                                                       0, i->size[no][j] * i->buf_cl_format_size [no],
                                                       0, NULL, NULL, &cl_err);
                        if (cl_err != CL_SUCCESS) CL_ERROR;

                        /* color conversion will be performed in the GPU later */
                        /* get buffer data using multiple worker threads
                           to increase bandwidth */
                        gegl_buffer_cl_worker_transf (i->buffer[no], data, i->buf_cl_format_size [no], i->roi[no][j], FALSE);

                        cl_err = gegl_clEnqueueUnmapMemObject (gegl_cl_get_command_queue(), i->tex_buf[no][j], data,
                                                               0, NULL, NULL);
                        if (cl_err != CL_SUCCESS) CL_ERROR;
                      }

                    g_assert (i->tex_op[no][j] == NULL);
                    i->tex_op[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                            CL_MEM_READ_WRITE,
                                                            i->size[no][j] * i->op_cl_format_size [no],
                                                            NULL, &cl_err);
                    if (cl_err != CL_SUCCESS) CL_ERROR;

                    /* color conversion in the GPU (input) */
                    g_assert (i->tex_buf[no][j] && i->tex_op[no][j]);
                    cl_err = gegl_cl_color_conv (i->tex_buf[no][j], i->tex_op[no][j], i->size[no][j],
                                                 i->buffer[no]->soft_format, i->format[no]);
                    if (cl_err == FALSE) CL_ERROR;

                    i->tex[no][j] = i->tex_op[no][j];

                    break;
                    }
                }
            }

          /* Wait Processing */
          cl_err = gegl_clEnqueueBarrier(gegl_cl_get_command_queue());
          if (cl_err != CL_SUCCESS) CL_ERROR;
        }
      else if (i->flags[no] == GEGL_CL_BUFFER_WRITE)
        {
          for (j=0; j < i->n; j++)
            {
              switch (i->conv[no])
                {
                  case GEGL_CL_COLOR_NOT_SUPPORTED:

                  {
                  g_assert (i->tex_op[no][j] == NULL);
                  i->tex_op[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                          CL_MEM_ALLOC_HOST_PTR | CL_MEM_WRITE_ONLY,
                                                          i->size[no][j] * i->op_cl_format_size [no],
                                                          NULL, &cl_err);
                  if (cl_err != CL_SUCCESS) CL_ERROR;

                  i->tex[no][j] = i->tex_op[no][j];

                  break;
                  }

                  case GEGL_CL_COLOR_EQUAL:

                  {
                  g_assert (i->tex_buf[no][j] == NULL);
                  i->tex_buf[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                           CL_MEM_ALLOC_HOST_PTR | CL_MEM_READ_WRITE, /* cache */
                                                           i->size[no][j] * i->buf_cl_format_size [no],
                                                           NULL, &cl_err);
                  if (cl_err != CL_SUCCESS) CL_ERROR;

                  i->tex[no][j] = i->tex_buf[no][j];

                  break;
                  }

                  case GEGL_CL_COLOR_CONVERT:

                  {
                  g_assert (i->tex_buf[no][j] == NULL);
                  i->tex_buf[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                           CL_MEM_ALLOC_HOST_PTR | CL_MEM_READ_WRITE, /* cache */
                                                           i->size[no][j] * i->buf_cl_format_size [no],
                                                           NULL, &cl_err);
                  if (cl_err != CL_SUCCESS) CL_ERROR;

                  g_assert (i->tex_op[no][j] == NULL);
                  i->tex_op[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                          CL_MEM_READ_WRITE,
                                                          i->size[no][j] * i->op_cl_format_size [no],
                                                          NULL, &cl_err);
                  if (cl_err != CL_SUCCESS) CL_ERROR;

                  i->tex[no][j] = i->tex_op[no][j];

                  break;
                  }
               }
            }
        }
      else if (i->flags[no] == GEGL_CL_BUFFER_AUX)
        {
          for (j=0; j < i->n; j++)
            {
              g_assert (i->tex_op[no][j] == NULL);
              i->tex_op[no][j] = gegl_clCreateBuffer (gegl_cl_get_context (),
                                                      CL_MEM_READ_WRITE,
                                                      i->size[no][j] * i->op_cl_format_size [no],
                                                      NULL, &cl_err);
              if (cl_err != CL_SUCCESS) CL_ERROR;

              i->tex[no][j] = i->tex_op[no][j];
            }
        }
    }

  i->roi_no += i->n;

  i->iteration_no++;

  if (result == FALSE)
    {
      for (no=0; no<i->iterators;no++)
        {
          if (i->buffer[no])
            {
              gint j;
              gboolean found = FALSE;
              for (j=0; j<no; j++)
                if (i->buffer[no]==i->buffer[j])
                  {
                    found = TRUE;
                    break;
                  }
              if (!found)
                gegl_buffer_unlock (i->buffer[no]);

              g_object_unref (i->buffer[no]);
            }
        }

      i->is_finished = TRUE;

      g_free (i->roi_all);
      g_slice_free (GeglBufferClIterators, i);
    }

  *err = FALSE;
  return result;

error:

  for (no=0; no<i->iterators;no++)
    for (j=0; j < i->n; j++)
      {
        if (i->tex_buf[no][j]) gegl_clReleaseMemObject (i->tex_buf[no][j]);
        if (i->tex_op [no][j]) gegl_clReleaseMemObject (i->tex_op [no][j]);

        i->tex    [no][j] = NULL;
        i->tex_buf[no][j] = NULL;
        i->tex_op [no][j] = NULL;
      }

  *err = TRUE;
  return FALSE;
}
gboolean gegl_buffer_iterator_next     (GeglBufferIterator *iterator)
{
  GeglBufferIterators *i = (gpointer)iterator;
  gboolean result = FALSE;
  gint no;

  if (i->is_finished)
    g_error ("%s called on finished buffer iterator", G_STRFUNC);
  if (i->iteration_no == 0)
    {
      for (no=0; no<i->iterators;no++)
        {
          gint j;
          gboolean found = FALSE;
          for (j=0; j<no; j++)
            if (i->buffer[no]==i->buffer[j])
              {
                found = TRUE;
                break;
              }
          if (!found)
            gegl_buffer_lock (i->buffer[no]);
        }
    }
  else
    {
      /* complete pending write work */
      for (no=0; no<i->iterators;no++)
        {
          if (i->flags[no] & GEGL_BUFFER_WRITE)
            {

              if (i->flags[no] & GEGL_BUFFER_SCAN_COMPATIBLE &&
                  i->flags[no] & GEGL_BUFFER_FORMAT_COMPATIBLE &&
                  i->roi[no].width == i->i[no].buffer->tile_storage->tile_width && (i->flags[no] & GEGL_BUFFER_FORMAT_COMPATIBLE))
                {
                   /* direct access */
#if DEBUG_DIRECT
                   direct_write += i->roi[no].width * i->roi[no].height;
#endif
                }
              else
                {
#if DEBUG_DIRECT
                  in_direct_write += i->roi[no].width * i->roi[no].height;
#endif

                  ensure_buf (i, no);

  /* XXX: should perhaps use _set_unlocked, and keep the lock in the
   * iterator.
   */
                  gegl_buffer_set (i->buffer[no], &(i->roi[no]), i->format[no], i->buf[no], GEGL_AUTO_ROWSTRIDE);
                }
            }
        }
    }

  g_assert (i->iterators > 0);

  /* then we iterate all */
  for (no=0; no<i->iterators;no++)
    {
      if (i->flags[no] & GEGL_BUFFER_SCAN_COMPATIBLE)
        {
          gboolean res;
          res = gegl_buffer_tile_iterator_next (&i->i[no]);
          if (no == 0)
            {
              result = res;
            }
          i->roi[no] = i->i[no].roi2;

          /* since they were scan compatible this should be true */
          if (res != result)
            {
              g_print ("%i==%i != 0==%i\n", no, res, result);
            }
          g_assert (res == result);

          if ((i->flags[no] & GEGL_BUFFER_FORMAT_COMPATIBLE) &&
              i->roi[no].width == i->i[no].buffer->tile_storage->tile_width
           )
            {
              /* direct access */
              i->data[no]=i->i[no].sub_data;
#if DEBUG_DIRECT
              direct_read += i->roi[no].width * i->roi[no].height;
#endif
            }
          else
            {
              ensure_buf (i, no);

              if (i->flags[no] & GEGL_BUFFER_READ)
                {
                  gegl_buffer_get_unlocked (i->buffer[no], 1.0, &(i->roi[no]), i->format[no], i->buf[no], GEGL_AUTO_ROWSTRIDE);
                }

              i->data[no]=i->buf[no];
#if DEBUG_DIRECT
              in_direct_read += i->roi[no].width * i->roi[no].height;
#endif
            }
        }
      else
        {
          /* we copy the roi from iterator 0  */
          i->roi[no] = i->roi[0];
          i->roi[no].x += (i->rect[no].x-i->rect[0].x);
          i->roi[no].y += (i->rect[no].y-i->rect[0].y);

          ensure_buf (i, no);

          if (i->flags[no] & GEGL_BUFFER_READ)
            {
              gegl_buffer_get_unlocked (i->buffer[no], 1.0, &(i->roi[no]), i->format[no], i->buf[no], GEGL_AUTO_ROWSTRIDE);
            }
          i->data[no]=i->buf[no];

#if DEBUG_DIRECT
          in_direct_read += i->roi[no].width * i->roi[no].height;
#endif
        }
      i->length = i->roi[no].width * i->roi[no].height;
    }

  i->iteration_no++;

  if (result == FALSE)
    {
      for (no=0; no<i->iterators;no++)
        {
          gint j;
          gboolean found = FALSE;
          for (j=0; j<no; j++)
            if (i->buffer[no]==i->buffer[j])
              {
                found = TRUE;
                break;
              }
          if (!found)
            gegl_buffer_unlock (i->buffer[no]);
        }

      for (no=0; no<i->iterators;no++)
        {
          if (i->buf[no])
            iterator_buf_pool_release (i->buf[no]);
          i->buf[no]=NULL;
          g_object_unref (i->buffer[no]);
        }
#if DEBUG_DIRECT
      g_print ("%f %f\n", (100.0*direct_read/(in_direct_read+direct_read)),
                           100.0*direct_write/(in_direct_write+direct_write));
#endif
      i->is_finished = TRUE;
      g_slice_free (GeglBufferIterators, i);
    }


  return result;
}
Example #5
0
static void inline
gegl_sampler_get_pixel (GeglSampler    *sampler,
                        gint            x,
                        gint            y,
                        gpointer        data,
                        GeglAbyssPolicy repeat_mode)
{
  GeglSamplerNearest *nearest_sampler = (GeglSamplerNearest*)(sampler);
  GeglBuffer *buffer = sampler->buffer;
  const GeglRectangle *abyss = &buffer->abyss;
  guchar              *buf   = data;

  if (y <  abyss->y ||
      x <  abyss->x ||
      y >= abyss->y + abyss->height ||
      x >= abyss->x + abyss->width)
    {
      switch (repeat_mode)
      {
        case GEGL_ABYSS_CLAMP:
          x = CLAMP (x, abyss->x, abyss->x+abyss->width-1);
          y = CLAMP (y, abyss->y, abyss->y+abyss->height-1);
          break;

        case GEGL_ABYSS_LOOP:
          x = abyss->x + GEGL_REMAINDER (x - abyss->x, abyss->width);
          y = abyss->y + GEGL_REMAINDER (y - abyss->y, abyss->height);
          break;

        case GEGL_ABYSS_BLACK:
          {
            gfloat color[4] = {0.0, 0.0, 0.0, 1.0};
            babl_process (babl_fish (gegl_babl_rgba_linear_float (), sampler->format),
                          color,
                          buf,
                          1);
            return;
          }

        case GEGL_ABYSS_WHITE:
          {
            gfloat color[4] = {1.0, 1.0, 1.0, 1.0};
            babl_process (babl_fish (gegl_babl_rgba_linear_float (),
                                     sampler->format),
                          color,
                          buf,
                          1);
            return;
          }

        default:
        case GEGL_ABYSS_NONE:
          memset (buf, 0x00, babl_format_get_bytes_per_pixel (sampler->format));
          return;
      }
    }

  gegl_buffer_lock (sampler->buffer);

  {
    gint tile_width  = buffer->tile_width;
    gint tile_height = buffer->tile_height;
    gint tiledy      = y + buffer->shift_y;
    gint tiledx      = x + buffer->shift_x;
    gint indice_x    = gegl_tile_indice (tiledx, tile_width);
    gint indice_y    = gegl_tile_indice (tiledy, tile_height);

    GeglTile *tile = nearest_sampler->hot_tile;

    if (!(tile &&
          tile->x == indice_x &&
          tile->y == indice_y))
      {
        if (gegl_config_threads()>1)
          g_rec_mutex_lock (&buffer->tile_storage->mutex);

        if (tile)
          gegl_tile_unref (tile);

        tile = gegl_tile_source_get_tile ((GeglTileSource *) (buffer),
                                          indice_x, indice_y,
                                          0);
        nearest_sampler->hot_tile = tile;

        if (gegl_config_threads()>1)
          g_rec_mutex_unlock (&buffer->tile_storage->mutex);
      }

    if (tile)
      {
        gint tile_origin_x = indice_x * tile_width;
        gint tile_origin_y = indice_y * tile_height;
        gint       offsetx = tiledx - tile_origin_x;
        gint       offsety = tiledy - tile_origin_y;

        guchar *tp = gegl_tile_get_data (tile) + (offsety * tile_width + offsetx) * nearest_sampler->buffer_bpp;

        babl_process (sampler->fish, tp, buf, 1);
      }
  }

  gegl_buffer_unlock (sampler->buffer);
}