61 lines
1.6 KiB
C++
61 lines
1.6 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <https://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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*/
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/*
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*
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* Instancing routines
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*
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*/
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#include <stdlib.h>
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#include "dxxerror.h"
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#include "3d.h"
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#include "globvars.h"
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namespace dcx {
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//instance at specified point with specified orientation
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//if matrix==NULL, don't modify matrix. This will be like doing an offset
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g3_instance_context g3_start_instance_matrix()
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{
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return {View_matrix, View_position};
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}
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g3_instance_context g3_start_instance_matrix(const vms_vector &pos, const vms_matrix &orient)
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{
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auto r = g3_start_instance_matrix();
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//step 1: subtract object position from view position
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const auto tempv = vm_vec_sub(View_position, pos);
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//step 2: rotate view vector through object matrix
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vm_vec_rotate(View_position, tempv, orient);
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//step 3: rotate object matrix through view_matrix (vm = ob * vm)
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View_matrix = vm_matrix_x_matrix(vm_transposed_matrix(orient), View_matrix);
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return r;
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}
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//instance at specified point with specified orientation
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//if angles==NULL, don't modify matrix. This will be like doing an offset
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g3_instance_context g3_start_instance_angles(const vms_vector &pos, const vms_angvec &angles)
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{
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const auto &&tm = vm_angles_2_matrix(angles);
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return g3_start_instance_matrix(pos, tm);
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}
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//pops the old context
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void g3_done_instance(const g3_instance_context &ctx)
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{
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View_position = ctx.position;
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View_matrix = ctx.matrix;
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}
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}
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