www.pudn.com > LightTrack.rar > Clipp3D.cpp
/** 3DGPL *************************************************\
* () *
* 3-D volume and Z clipping. *
* *
* Defines: *
* C_volume_clipping Out of view-volume elements; *
* *
* C_line_z_clipping Clipping a line; *
* C_polygon_z_clipping View plane cliping; *
* C_line_xyz_clipping Arbitrry clipping of a line; *
* C_polygon_xyz_clipping Arbitrry plane cliping. *
* *
* (c) 1995-98 Sergei Savchenko, (savs@cs.mcgill.ca) *
\**********************************************************/
//Clipp3D.cpp
#include "LightTrack.h" /* HW_copy_int stuff */
#include "Trans.h" /* T_plane etc. */
#include "Clipper.h" /* clipping constants */
#include /* INT_MAX & INT_MIN */
int C_3D_clipping; /* type of performed clipping */
/**********************************************************\
* Accept/reject volume clipping. *
* *
* RETURNS: 0 when extend is for sure outside the *
* -------- view volume, just discard it; *
* -1 when further clipping is required; *
* 1 when element has a fair chance to be *
* inside the view volume, and should be *
* clipped by 2-D clipping when rasterizing. *
* *
* | z *
* \ | / Clipping volume is a pyramid *
* \ | / with 90 degree angle, *
* \ | / so the real view volume *
* -x>z \ | / x>z better be inside it. *
* \|/ *
* --------+--------- x *
* z>1;
whereto=m[2] 2-2'-5'-6-1-2 *
* |5' *
* 5*-*-----*6 If first vertex in the line is *
* / | \ clipped, both vertices are copyed, *
* 4* | *1 If no clipping or second one is *
* \ | / clipped then only second one is *
* 3*-*-----*2 copyed. If both vertices are *
* |2' clipped, neither one is copyed. *
* *
\***********************************************************/
int C_polygon_z_clipping(int *from,register int *to,
int dimension,int length
)
{
register int i;
int *v1,*v2,new_lng=0;
int *first_vrtx=to; /* begining of the source */
for(i=0;iC_TOLERANCE)
) /* not close enough */
{
if(whereto==1) { t=l; l=m; m=t; }
else { t=r; r=m; m=t; }
for(i=0;i>1;
whereto=T_vertex_on_plane(m,plane)<0;
}
*vmn=m; /* that is why m[] is static */
C_3D_clipping=swap^1;
}
return(1); /* partialy or not clipped */
}
}
/**********************************************************\
* Creating a polygon clipped by any plane. *
* *
* RETURNS: number of vertices in the clipped polygon. *
* -------- (0 when compleately clipped) *
* *
* 1-2-3-4-5-6-1 -> 2'-3'-5'-6' *
* \ 5' *
* 5*-*------*6 If first vertex in the line is *
* / \ \ being clipped both vertices are *
* 4* \ *1 copyed If no clipping or second *
* \ \ 3' / one is clipped then only second *
* 3*-----*--*2 one is copyed. If both vertices *
* \ are clipped, neither is copyed. *
* *
\**********************************************************/
int C_polygon_xyz_clipping(int *from,register int *to,
int *by1,int *by2,int *by3,
int dimension,int length
)
{
register int i;
int *v1,*v2,new_lng=0;
int *first_vrtx=to; /* begining of the source */
for(i=0;i