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/* Copyright (C) 2000 Damir Zucic */
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/*=============================================================================
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Check which atoms are inside the semi-spherical slab. Semi-spher.
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slab is defined by two concentric spheres and a single plane,
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passing through the slab center. A given atom is inside the slab
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if it is outside the inner sphere, inside the outer sphere and in
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front of the plane. Use this slab type to hide the entire rear
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half as well as the inner part of a globular protein. The position
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of the plane is fixed, while the position of both spherical
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surfaces may be adjusted.
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(1) Pointer to MolComplexS structure.
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(1) Slab flag set for each atom. The value one is assigned to
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atoms inside the slab, zero to the rest.
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The number of atoms inside the slab.
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========includes:============================================================*/
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#include <X11/Xutil.h>
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#include <X11/Xatom.h>
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/*======semi-spherical slab:=================================================*/
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size_t HalfSphereSlab_ (MolComplexS *curr_mol_complexSP)
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size_t atoms_inside_slabN = 0;
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double x0, y0, z0, r0_squared, r1_squared;
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double x, y, z, rho_squared, r_squared;
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/* The number of atoms in a complex: */
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atomsN = curr_mol_complexSP->atomsN;
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/* Copy the slab center coordinates: */
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x0 = curr_mol_complexSP->slab_center_vectorS.x;
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y0 = curr_mol_complexSP->slab_center_vectorS.y;
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z0 = curr_mol_complexSP->slab_center_vectorS.z;
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r0_squared = curr_mol_complexSP->slab_back_relative_position;
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r0_squared *= r0_squared;
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r1_squared = curr_mol_complexSP->slab_front_relative_position;
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r1_squared *= r1_squared;
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/* Set the slab flag for each atom: */
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for (atomI = 0; atomI < atomsN; atomI++)
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/** Pointer to the current atom: **/
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curr_atomSP = curr_mol_complexSP->atomSP + atomI;
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/** Set the initial values of slab flags to one; this **/
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/** will be changed later for atoms outside the slab: **/
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curr_atomSP->inside_slabF = 1;
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curr_atomSP->inside_projected_slabF = 1;
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/** Distance between the current atom and the cylinder axis: **/
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x = curr_atomSP->raw_atomS.x[0] - x0;
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z = curr_atomSP->raw_atomS.z[0] - z0;
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rho_squared = x * x + z * z;
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/** Distance between the current atom and the slab center: **/
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y = curr_atomSP->raw_atomS.y - y0;
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r_squared = rho_squared + y * y;
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/** First prepare the inside_projected_slabF: */
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if (rho_squared < r0_squared) curr_atomSP->inside_projected_slabF = 0;
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if (rho_squared > r1_squared) curr_atomSP->inside_projected_slabF = 0;
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/** If atom is behind the back plane, set slab **/
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/** flags to zero and go to check the next atom: **/
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curr_atomSP->inside_slabF = 0;
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curr_atomSP->inside_projected_slabF = 0;
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/** If atom is inside the inner slab sphere: **/
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if (r_squared < r0_squared)
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curr_atomSP->inside_slabF = 0;
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/** If atom is outside the outer slab sphere: **/
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if (r_squared > r1_squared)
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curr_atomSP->inside_slabF = 0;
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/** If this points is reached, current atom is inside the slab: **/
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atoms_inside_slabN++;
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/* Return the number of atoms inside the slab: */
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return atoms_inside_slabN;
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/*===========================================================================*/
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half_sphere_slab.c
