lamino-filters/src/lamino_bp_generic.cl

// all kernels must process volme voxelwise
// please be careful with local and global workers
// we need a 3D processing (not 2D)

// using tests we show max volume grosse: 1024 x 1024 x 256 or 2048 x 2048 x 64
// theory: 223 MB (CL_DEVICE_MAX_MEM_ALLOC_SIZE) x 5 cards / 4 Bytes (Float) = 1024 x 1024 x 278 voxels

#include <lamino-filter-def.h>

#define PI      3.1415926535897932384626433832795028841971693993751
#define PI_2    1.5707963267948966192313216916397514420985846996876

float
interpolate (global float *proj,
             global CLParameters *param,
             float oldx,
             float oldy)
{
    /* Check if vertically out of projection plane boundaries */
    if (oldy < 0)
        oldy = 0.5;;

    if (oldy > param->proj_sy)
        oldy = param->proj_sy - 0.5;

    /* bilinear interpolation */
    const float yf_1 = oldy - floor(oldy);
    const float yf_0 = 1.0f - yf_1;
    const float xf_1 = oldx - floor(oldx);
    const float xf_0 = 1.0f  - xf_1;

    const int base = ((int) floor(oldx)) + ((int) floor(oldy)) * param->proj_sx;
    float result;

    result  = proj[base    ] * xf_0 * yf_0;
    result += proj[base + 1] * xf_1 * yf_0;
    result += proj[base + param->proj_sx    ] * xf_0 * yf_1;
    result += proj[base + param->proj_sx + 1] * xf_1 * yf_1;
    return result;
}

kernel void
lamino_bp_generic (global float *proj,
				   global float *volume,
				   global CLParameters *param)
{
    const ushort vX = get_global_id(0);
    const ushort vY = get_global_id(1);
    const ushort vZ = get_global_id(2);

    const long int idx = (vZ * get_global_size(1) * get_global_size(0)) +
                         (vY * get_global_size(0)) + vX;

    const float newz = (float) vZ * param->z_spacing - param->vol_oz;
    const float newy = (float) vY - param->vol_oy;
    const float newx = (float) vX - param->vol_ox;

    const float oldx = newx * param->mat_0 + newy * param->mat_1 + newz * param->mat_2 + param->proj_ox;
    const float oldy = newx * param->mat_3 + newy * param->mat_4 + newz * param->mat_5 + param->proj_oy;

    volume[idx] += interpolate (proj, param, oldx, oldy);
}

kernel void
lamino_bp_varied (global float *proj,
                  global float *volume,
                  global CLParameters *param)
{
    const ushort vX = get_global_id(0);
    const ushort vY = get_global_id(1);
    const ushort vZ = get_global_id(2);

    const long int idx = (vZ * get_global_size(1) * get_global_size(0)) +
                         (vY * get_global_size(0)) + vX;

    const float newz = (float) vZ * param->z_spacing - param->vol_oz;
    const float newy = (float) vY - param->vol_oy;
    const float newx = (float) vX - param->vol_ox;

    /* Vary alpha depending on the z height */
    const float alpha = -3 * PI_2 + param->theta;

    const float cf = cos(param->phi);
    const float ct = cos(alpha);
    const float cg = cos(param->psi);
    const float sf = sin(param->phi);
    const float st = sin(alpha);
    const float sg = sin(param->psi);

    const float mat_0 =  cg * cf - sg * st * sf;
    const float mat_1 = -cg * sf - sg * st * cf;
    const float mat_2 = -sg * ct;
    const float mat_3 =  sg * cf + cg * st * sf;
    const float mat_4 = -sg * sf + cg * st * cf;
    const float mat_5 =  cg * ct;

    /* Force newz values to be equal to 0 */
    const float oldx = newx * mat_0 + newy * mat_1 /* + newz * mat_2 */ + param->proj_ox + newz / param->vol_sz * param->proj_ox_variation;
    const float oldy = newx * mat_3 + newy * mat_4 /* + newz * mat_5 */ + param->proj_oy;

    volume[idx] += interpolate (proj, param, oldx, oldy);
}

kernel void
lamino_clean_vol (global float *volume)
{
    const ushort vX = get_global_id(0);
    const ushort vY = get_global_id(1);
    const ushort vZ = get_global_id(2);

    const ushort vSX = get_global_size(0);
    const ushort vSY = get_global_size(1);
    const ushort vSZ = get_global_size(2);

    const int idx = (vZ * vSY * vSX) + (vY * vSX) + vX;

    volume[idx] = 0;
}

kernel void
lamino_norm_vol(global float *volume,
				const float factor)
{
    const ushort vX = get_global_id(0);
    const ushort vY = get_global_id(1);
    const ushort vZ = get_global_id(2);

    const ushort vSX = get_global_size(0);
    const ushort vSY = get_global_size(1);
    const ushort vSZ = get_global_size(2);

    const int idx = (vZ * vSY * vSX) + (vY * vSX) + vX;
    //const int idx = (vY * vSX) + vX;

    float val = volume[idx] * factor;
    volume[idx] = val;
}