85 lines
1.9 KiB
C++
85 lines
1.9 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <http://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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namespace {
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struct instance_context {
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vms_matrix m;
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vms_vector p;
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};
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}
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static array<instance_context, 5> instance_stack;
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int instance_depth = 0;
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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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void g3_start_instance_matrix(const vms_vector &pos,const vms_matrix *orient)
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{
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assert(instance_depth < instance_stack.size());
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instance_stack[instance_depth].m = View_matrix;
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instance_stack[instance_depth].p = View_position;
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instance_depth++;
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//step 1: subtract object position from view position
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if (orient) {
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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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}
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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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void g3_start_instance_angles(const vms_vector &pos,const vms_angvec *angles)
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{
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if (angles==NULL) {
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g3_start_instance_matrix(pos,NULL);
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return;
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}
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const auto tm = vm_angles_2_matrix(*angles);
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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()
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{
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instance_depth--;
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Assert(instance_depth >= 0);
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View_position = instance_stack[instance_depth].p;
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View_matrix = instance_stack[instance_depth].m;
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}
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}
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