mirror of
https://github.com/kevinbentley/Descent3.git
synced 2026-04-08 14:00:07 -04:00
Initial import
This commit is contained in:
Kevin Bentley
435
renderer/SoftwareClipper.cpp
Normal file
435
renderer/SoftwareClipper.cpp
Normal file
@@ -0,0 +1,435 @@
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#include "RendererConfig.h"
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#ifdef USE_SOFTWARE_TNL
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#include "pserror.h"
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#include "3d.h"
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#include "SoftwareInternal.h"
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static int free_point_num = -1;
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static g3Point temp_points[MAX_POINTS_IN_POLY];
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static g3Point *free_points[MAX_POINTS_IN_POLY];
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vector Clip_plane_point;
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void InitFreePoints(void)
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{
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int i;
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for( i = 0; i < MAX_POINTS_IN_POLY; i++ )
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{
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free_points[i] = &temp_points[i];
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}
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free_point_num = 0;
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}
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g3Point *GetTempPoint(void)
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{
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ASSERT(free_point_num < MAX_POINTS_IN_POLY);
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g3Point *p = free_points[ free_point_num++ ];
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p->p3_flags = PF_TEMP_POINT;
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return p;
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}
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void FreeTempPoint(g3Point *p)
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{
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if( free_point_num < 1 )
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{
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mprintf((1,"clipper: no temp points to free\n"));
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free_point_num = 1;
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Int3();
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}
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ASSERT( p->p3_flags & PF_TEMP_POINT );
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free_points[ --free_point_num ] = p;
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p->p3_flags &= ~PF_TEMP_POINT;
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}
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//Verify that all the temp points are free, and free them it they are not.
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#ifdef _DEBUG
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void CheckTempPoints(void)
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{
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if( free_point_num )
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{
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Int3();
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InitFreePoints();
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}
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}
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#endif
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//Free up any temp points (created by the clipper) in the given pointlist
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//Parameters: pointlist - pointer to list of pointers to points, returned by g3_ClipPolygon()
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// nv - the number of points in pointlist
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void g3_FreeTempPoints( g3Point **pointlist, int nv )
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{
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// Go through list
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int i;
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for( i = 0; i < nv; i++ )
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{
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if( pointlist[i]->p3_flags & PF_TEMP_POINT )
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{
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FreeTempPoint( pointlist[i] );
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}
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}
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// Make sure all temp points are freed
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CheckTempPoints();
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}
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// Clips an edge against the far plane
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g3Point *ClipFarEdge( g3Point *on_pnt, g3Point *off_pnt )
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{
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float z_on = on_pnt->p3_z;
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float z_off = off_pnt->p3_z;
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float k = 1.0f - ((z_off-Far_clip_z) / (z_off-z_on));
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g3Point *tmp = GetTempPoint();
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tmp->p3_z = on_pnt->p3_z + ((off_pnt->p3_z-on_pnt->p3_z) * k);
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tmp->p3_x = on_pnt->p3_x + ((off_pnt->p3_x-on_pnt->p3_x) * k);
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tmp->p3_y = on_pnt->p3_y + ((off_pnt->p3_y-on_pnt->p3_y) * k);
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if (on_pnt->p3_flags & PF_UV)
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{
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tmp->p3_u = on_pnt->p3_u + ((off_pnt->p3_u-on_pnt->p3_u) * k);
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tmp->p3_v = on_pnt->p3_v + ((off_pnt->p3_v-on_pnt->p3_v) * k);
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tmp->p3_flags |= PF_UV;
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}
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if (on_pnt->p3_flags & PF_UV2)
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{
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tmp->p3_u2 = on_pnt->p3_u2 + ((off_pnt->p3_u2-on_pnt->p3_u2) * k);
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tmp->p3_v2 = on_pnt->p3_v2 + ((off_pnt->p3_v2-on_pnt->p3_v2) * k);
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tmp->p3_flags |= PF_UV2;
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}
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if (on_pnt->p3_flags & PF_L)
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{
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tmp->p3_l = on_pnt->p3_l + ((off_pnt->p3_l-on_pnt->p3_l) * k);
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tmp->p3_flags |= PF_L;
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}
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if (on_pnt->p3_flags & PF_RGBA)
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{
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tmp->p3_r = on_pnt->p3_r + ((off_pnt->p3_r-on_pnt->p3_r) * k);
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tmp->p3_g = on_pnt->p3_g + ((off_pnt->p3_g-on_pnt->p3_g) * k);
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tmp->p3_b = on_pnt->p3_b + ((off_pnt->p3_b-on_pnt->p3_b) * k);
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tmp->p3_a = on_pnt->p3_a + ((off_pnt->p3_a-on_pnt->p3_a) * k);
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tmp->p3_flags |= PF_RGBA;
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}
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g3_CodePoint(tmp);
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return tmp;
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}
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// Clips an edge against the far plane
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g3Point *ClipCustomEdge( g3Point *on_pnt, g3Point *off_pnt )
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{
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g3Point *tmp = GetTempPoint();
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vector ray_direction = off_pnt->p3_vec - on_pnt->p3_vec;
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ray_direction.x /= Matrix_scale.x;
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ray_direction.y /= Matrix_scale.y;
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ray_direction.z /= Matrix_scale.z;
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vector w = on_pnt->p3_vec - Clip_plane_point;
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w.x /= Matrix_scale.x;
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w.y /= Matrix_scale.y;
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w.z /= Matrix_scale.z;
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float k, den = -(Clip_plane * ray_direction);
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if( den == 0.0f )
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{
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k = 1.0f;
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}
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else
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{
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float num = Clip_plane * w;
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k = num / den;
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}
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tmp->p3_vec = on_pnt->p3_vec + ((off_pnt->p3_vec-on_pnt->p3_vec) * k);
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if (on_pnt->p3_flags & PF_UV)
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{
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tmp->p3_u = on_pnt->p3_u + ((off_pnt->p3_u-on_pnt->p3_u) * k);
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tmp->p3_v = on_pnt->p3_v + ((off_pnt->p3_v-on_pnt->p3_v) * k);
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tmp->p3_flags |= PF_UV;
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}
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if (on_pnt->p3_flags & PF_UV2)
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{
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tmp->p3_u2 = on_pnt->p3_u2 + ((off_pnt->p3_u2-on_pnt->p3_u2) * k);
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tmp->p3_v2 = on_pnt->p3_v2 + ((off_pnt->p3_v2-on_pnt->p3_v2) * k);
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tmp->p3_flags |= PF_UV2;
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}
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if (on_pnt->p3_flags & PF_L)
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{
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tmp->p3_l = on_pnt->p3_l + ((off_pnt->p3_l-on_pnt->p3_l) * k);
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tmp->p3_flags |= PF_L;
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}
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if (on_pnt->p3_flags & PF_RGBA)
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{
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tmp->p3_r = on_pnt->p3_r + ((off_pnt->p3_r-on_pnt->p3_r) * k);
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tmp->p3_g = on_pnt->p3_g + ((off_pnt->p3_g-on_pnt->p3_g) * k);
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tmp->p3_b = on_pnt->p3_b + ((off_pnt->p3_b-on_pnt->p3_b) * k);
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tmp->p3_a = on_pnt->p3_a + ((off_pnt->p3_a-on_pnt->p3_a) * k);
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tmp->p3_flags |= PF_RGBA;
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}
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g3_CodePoint(tmp);
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return tmp;
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}
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//clips an edge against one plane.
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g3Point *ClipEdge( int plane_flag, g3Point *on_pnt, g3Point *off_pnt )
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{
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float a,b,k;
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g3Point *tmp;
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//compute clipping value k = (xs-zs) / (xs-xe-zs+ze)
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//use x or y as appropriate, and negate x/y value as appropriate
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if (plane_flag & CC_OFF_FAR)
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{
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return ClipFarEdge (on_pnt,off_pnt);
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}
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if ((plane_flag & CC_OFF_CUSTOM) && Clip_custom)
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{
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return ClipCustomEdge (on_pnt,off_pnt);
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}
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if (plane_flag & (CC_OFF_RIGHT | CC_OFF_LEFT))
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{
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a = on_pnt->p3_x;
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b = off_pnt->p3_x;
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}
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else
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{
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a = on_pnt->p3_y;
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b = off_pnt->p3_y;
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}
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if (plane_flag & (CC_OFF_LEFT | CC_OFF_BOT))
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{
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a = -a;
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b = -b;
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}
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k = (a - on_pnt->p3_z) / ((a - on_pnt->p3_z) - b + off_pnt->p3_z); //(xs-zs) / (xs-zs-xe+ze)
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tmp = GetTempPoint();
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tmp->p3_x = on_pnt->p3_x + ((off_pnt->p3_x-on_pnt->p3_x) * k);
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tmp->p3_y = on_pnt->p3_y + ((off_pnt->p3_y-on_pnt->p3_y) * k);
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if (plane_flag & (CC_OFF_TOP|CC_OFF_BOT))
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{
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tmp->p3_z = tmp->p3_y;
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}
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else
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{
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tmp->p3_z = tmp->p3_x;
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}
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if (plane_flag & (CC_OFF_LEFT|CC_OFF_BOT))
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{
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tmp->p3_z = -tmp->p3_z;
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}
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if (on_pnt->p3_flags & PF_UV)
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{
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tmp->p3_u = on_pnt->p3_u + ((off_pnt->p3_u-on_pnt->p3_u) * k);
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tmp->p3_v = on_pnt->p3_v + ((off_pnt->p3_v-on_pnt->p3_v) * k);
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tmp->p3_flags |= PF_UV;
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}
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if (on_pnt->p3_flags & PF_UV2)
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{
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tmp->p3_u2 = on_pnt->p3_u2 + ((off_pnt->p3_u2-on_pnt->p3_u2) * k);
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tmp->p3_v2 = on_pnt->p3_v2 + ((off_pnt->p3_v2-on_pnt->p3_v2) * k);
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tmp->p3_flags |= PF_UV2;
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}
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if (on_pnt->p3_flags & PF_L)
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{
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tmp->p3_l = on_pnt->p3_l + ((off_pnt->p3_l-on_pnt->p3_l) * k);
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tmp->p3_flags |= PF_L;
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}
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if (on_pnt->p3_flags & PF_RGBA)
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{
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tmp->p3_r = on_pnt->p3_r + ((off_pnt->p3_r-on_pnt->p3_r) * k);
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tmp->p3_g = on_pnt->p3_g + ((off_pnt->p3_g-on_pnt->p3_g) * k);
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tmp->p3_b = on_pnt->p3_b + ((off_pnt->p3_b-on_pnt->p3_b) * k);
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tmp->p3_a = on_pnt->p3_a + ((off_pnt->p3_a-on_pnt->p3_a) * k);
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tmp->p3_flags |= PF_RGBA;
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}
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g3_CodePoint(tmp);
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return tmp;
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}
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//clips a line to the viewing pyramid.
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void ClipLine(g3Point **p0,g3Point **p1,ubyte codes_or)
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{
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int plane_flag;
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g3Point *old_p1;
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//might have these left over
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//(*p0)->p3_flags &= ~(PF_UV|PF_L|PF_RGBA|PF_UV2);
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//(*p1)->p3_flags &= ~(PF_UV|PF_L|PF_RGBA|PF_UV2);
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for (plane_flag=1;plane_flag<=32;plane_flag<<=1)
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{
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if (codes_or & plane_flag)
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{
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if ((*p0)->p3_codes & plane_flag)
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{
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//swap!
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g3Point *t=*p0;
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*p0=*p1;
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*p1=t;
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}
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old_p1 = *p1;
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*p1 = ClipEdge(plane_flag,*p0,*p1);
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codes_or = (*p0)->p3_codes | (*p1)->p3_codes; //get new codes
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if (old_p1->p3_flags & PF_TEMP_POINT)
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{
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FreeTempPoint(old_p1);
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}
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}
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}
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}
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int ClipPlane(int plane_flag,g3Point **src,g3Point **dest,int *nv,g3Codes *cc)
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{
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int i,prev,next;
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g3Point **save_dest=dest;
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//Init codes
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cc->cc_and = 0xff; cc->cc_or = 0;
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for (i=0,prev=*nv-1,next=1;i<*nv;i++)
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{
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if (src[i]->p3_codes & plane_flag)
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{
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//cur point off?
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if (! (src[prev]->p3_codes & plane_flag))
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{
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//prev not off?
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*dest = ClipEdge(plane_flag,src[prev],src[i]);
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cc->cc_or |= (*dest)->p3_codes;
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cc->cc_and &= (*dest)->p3_codes;
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dest++;
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}
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if (! (src[next]->p3_codes & plane_flag))
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{
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*dest = ClipEdge(plane_flag,src[next],src[i]);
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cc->cc_or |= (*dest)->p3_codes;
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cc->cc_and &= (*dest)->p3_codes;
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dest++;
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}
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//see if must free discarded point
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if (src[i]->p3_flags & PF_TEMP_POINT)
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{
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FreeTempPoint(src[i]);
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}
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}
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else
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{
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//cur not off, copy to dest buffer
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*dest++ = src[i];
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cc->cc_or |= src[i]->p3_codes;
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cc->cc_and &= src[i]->p3_codes;
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}
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prev = i;
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if (++next == *nv)
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{
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next = 0;
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}
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}
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return (dest-save_dest);
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}
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//temp buffers for clipping
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static g3Point *Vbuf0[MAX_POINTS_IN_POLY];
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static g3Point *Vbuf1[MAX_POINTS_IN_POLY];
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//Clips a polygon
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//Parameters: pointlist - pointer to a list of pointers to points
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// nv - the number of points in the polygon
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// cc - the clip codes for this polygon
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//Returns: a pointer to a list of pointer of points in the clipped polygon
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//NOTE: You MUST call g3_FreeTempPoints() when you're done with the clipped polygon
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g3Point **g3_ClipPolygon(g3Point **pointlist,int *nv,g3Codes *cc)
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{
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int plane_flag;
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g3Point **dest;
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dest = Vbuf0;
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//& ASSERT(free_point_num == 0); //DAJ UTB CMO
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if(free_point_num!=0){
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mprintf((1,"clipper: leftover temp point\n"));
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free_point_num = 0;
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Int3();
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}
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for (plane_flag=1;plane_flag<=32;plane_flag<<=1)
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{
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if (cc->cc_or & plane_flag)
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{
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*nv = ClipPlane(plane_flag,pointlist,dest,nv,cc);
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if (cc->cc_and) //clipped away
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return dest;
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pointlist = dest;
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dest = (pointlist == Vbuf0) ? Vbuf1 : Vbuf0;
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}
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}
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return pointlist; //we swapped after we copied
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}
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// sets the z distance of the far clipping plane
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void g3_SetFarClipZ(float z)
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{
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Far_clip_z = z;
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}
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// Sets up a custom clipping plane - g3_StartFrame must be called before this is called
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void g3_SetCustomClipPlane(ubyte state,vector *pnt,vector *normal)
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{
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Clip_custom=state;
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if (state)
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{
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vector tempv;
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vector norm=*normal;
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tempv = *pnt - View_position;
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Clip_plane_point = tempv * View_matrix;
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Clip_plane=norm * Unscaled_matrix;//View_matrix;
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vm_NormalizeVector(&Clip_plane);
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}
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}
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#endif
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