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/*
* Copyright (C) 2011-2013 Karlsruhe Institute of Technology
*
* This file is part of Ufo.
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either
* version 3 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
constant sampler_t volumeSampler = CLK_NORMALIZED_COORDS_FALSE |
CLK_ADDRESS_CLAMP |
CLK_FILTER_LINEAR;
kernel void
backproject_nearest (global float *sinogram,
global float *slice,
constant float *sin_lut,
constant float *cos_lut,
const unsigned int x_offset,
const unsigned int y_offset,
const unsigned int angle_offset,
const unsigned n_projections,
const float axis_pos)
{
const int idx = get_global_id(0);
const int idy = get_global_id(1);
const int width = get_global_size(0);
const float bx = idx - axis_pos + x_offset + 0.5f;
const float by = idy - axis_pos + y_offset + 0.5f;
float sum = 0.0f;
for(int proj = 0; proj < n_projections; proj++) {
float h = axis_pos + bx * cos_lut[angle_offset + proj] + by * sin_lut[angle_offset + proj];
sum += sinogram[(int)(proj * width + h)];
}
slice[idy * width + idx] = sum * M_PI_F / n_projections;
}
kernel void
backproject_tex (read_only image2d_t sinogram,
global float *slice,
constant float *sin_lut,
constant float *cos_lut,
const unsigned int x_offset,
const unsigned int y_offset,
const unsigned int angle_offset,
const unsigned int n_projections,
const float axis_pos)
{
const int idx = get_global_id(0);
const int idy = get_global_id(1);
const float bx = idx - axis_pos + x_offset + 0.5f;
const float by = idy - axis_pos + y_offset + 0.5f;
float sum = 0.0f;
#ifdef DEVICE_TESLA_K20XM
#pragma unroll 4
#endif
#ifdef DEVICE_TESLA_P100_PCIE_16GB
#pragma unroll 2
#endif
#ifdef DEVICE_GEFORCE_GTX_TITAN_BLACK
#pragma unroll 8
#endif
#ifdef DEVICE_GEFORCE_GTX_TITAN
#pragma unroll 14
#endif
#ifdef DEVICE_GEFORCE_GTX_1080_TI
#pragma unroll 10
#endif
#ifdef DEVICE_QUADRO_M6000
#pragma unroll 2
#endif
#ifdef DEVICE_GFX1010
#pragma unroll 4
#endif
for(int proj = 0; proj < n_projections; proj++) {
float h = by * sin_lut[angle_offset + proj] + bx * cos_lut[angle_offset + proj] + axis_pos;
sum += read_imagef (sinogram, volumeSampler, (float2)(h, proj + 0.5f)).x;
}
slice[idy * get_global_size(0) + idx] = sum * M_PI_F / n_projections;
}
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