150 lines
4.7 KiB
C
150 lines
4.7 KiB
C
|
/*==========================================================================;
|
||
|
|
*
|
||
|
|
* Copyright (C) 1997 Microsoft Corporation. All Rights Reserved.
|
||
|
|
*
|
||
|
|
* File: clip.h
|
||
|
|
* Content: Template for functions to clip by a frustum side
|
||
|
|
*
|
||
|
|
* The following symbol should be defined before included this file:
|
||
|
|
* __CLIP_NAME - name for a function to clip triangles
|
||
|
|
* __CLIP_LINE_NAME - name for a function to clip lines
|
||
|
|
* __CLIP_W - if this functions are for Coord <= W. Otherwise they
|
||
|
|
* are for 0 < Coord
|
||
|
|
* __CLIP_COORD - should be hx, hy or hz
|
||
|
|
* __CLIP_FLAG - clipping flag to set
|
||
|
|
* __CLIP_GUARDBAND - defined when clipping by guardband window
|
||
|
|
* __CLIP_SIGN - "-" if clipping by left or bottom sides of guard band
|
||
|
|
* window
|
||
|
|
* __CLIP_GBCOEF - coefficient to multiply W when clipping by guard band
|
||
|
|
* window
|
||
|
|
*
|
||
|
|
* All these symbols are undefined at the end of this file
|
||
|
|
***************************************************************************/
|
||
|
|
//
|
||
|
|
// Clipping for triangle
|
||
|
|
//
|
||
|
|
// Returns number of vertices in the clipped triangle
|
||
|
|
//
|
||
|
|
int
|
||
|
|
__CLIP_NAME(D3DFE_PROCESSVERTICES *pv,
|
||
|
|
ClipVertex **inv,
|
||
|
|
ClipVertex **outv,
|
||
|
|
int count)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
int out_count = 0;
|
||
|
|
ClipVertex *curr, *prev;
|
||
|
|
D3DVALUE curr_inside;
|
||
|
|
D3DVALUE prev_inside;
|
||
|
|
|
||
|
|
prev = inv[count-1];
|
||
|
|
curr = *inv++;
|
||
|
|
#ifdef __CLIP_GUARDBAND
|
||
|
|
prev_inside = __CLIP_SIGN(prev->hw * pv->vcache.__CLIP_GBCOEF -
|
||
|
|
prev->__CLIP_COORD);
|
||
|
|
#else
|
||
|
|
#ifdef __CLIP_W
|
||
|
|
prev_inside = prev->hw - prev->__CLIP_COORD;
|
||
|
|
#else
|
||
|
|
prev_inside = prev->__CLIP_COORD;
|
||
|
|
#endif
|
||
|
|
#endif
|
||
|
|
for (i = count; i; i--)
|
||
|
|
{
|
||
|
|
#ifdef __CLIP_GUARDBAND
|
||
|
|
curr_inside = __CLIP_SIGN(curr->hw * pv->vcache.__CLIP_GBCOEF -
|
||
|
|
curr->__CLIP_COORD);
|
||
|
|
#else
|
||
|
|
#ifdef __CLIP_W
|
||
|
|
curr_inside = curr->hw - curr->__CLIP_COORD;
|
||
|
|
#else
|
||
|
|
curr_inside = curr->__CLIP_COORD;
|
||
|
|
#endif
|
||
|
|
#endif
|
||
|
|
// We interpolate always from the inside vertex to the outside vertex
|
||
|
|
// to reduce precision problems
|
||
|
|
if (FLOAT_LTZ(prev_inside))
|
||
|
|
{ // first point is outside
|
||
|
|
if (FLOAT_GEZ(curr_inside))
|
||
|
|
{ // second point is inside
|
||
|
|
// Find intersection and insert in into the output buffer
|
||
|
|
outv[out_count] = GET_NEW_CLIP_VERTEX;
|
||
|
|
Interpolate(pv,
|
||
|
|
outv[out_count],
|
||
|
|
curr, prev,
|
||
|
|
(prev->clip & CLIPPED_ENABLE) | __CLIP_FLAG,
|
||
|
|
curr_inside, curr_inside - prev_inside);
|
||
|
|
out_count++;
|
||
|
|
}
|
||
|
|
} else
|
||
|
|
{ // first point is inside - put it to the output buffer first
|
||
|
|
outv[out_count++] = prev;
|
||
|
|
if (FLOAT_LTZ(curr_inside))
|
||
|
|
{ // second point is outside
|
||
|
|
// Find intersection and put it to the output buffer
|
||
|
|
outv[out_count] = GET_NEW_CLIP_VERTEX;
|
||
|
|
Interpolate(pv,
|
||
|
|
outv[out_count],
|
||
|
|
prev, curr,
|
||
|
|
__CLIP_FLAG,
|
||
|
|
prev_inside, prev_inside - curr_inside);
|
||
|
|
out_count++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
prev = curr;
|
||
|
|
curr = *inv++;
|
||
|
|
prev_inside = curr_inside;
|
||
|
|
}
|
||
|
|
return out_count;
|
||
|
|
}
|
||
|
|
//-------------------------------------------------------------------------
|
||
|
|
// Clipping for lines
|
||
|
|
//
|
||
|
|
// Returns 1 if the line is outside the frustum, 0 otherwise
|
||
|
|
//
|
||
|
|
int __CLIP_LINE_NAME(D3DFE_PROCESSVERTICES *pv, ClipTriangle *line)
|
||
|
|
{
|
||
|
|
D3DVALUE in1, in2;
|
||
|
|
ClipVertex outv;
|
||
|
|
#ifdef __CLIP_GUARDBAND
|
||
|
|
in1 = __CLIP_SIGN(line->v[0]->hw * pv->vcache.__CLIP_GBCOEF -
|
||
|
|
line->v[0]->__CLIP_COORD);
|
||
|
|
in2 = __CLIP_SIGN(line->v[1]->hw * pv->vcache.__CLIP_GBCOEF -
|
||
|
|
line->v[1]->__CLIP_COORD);
|
||
|
|
#else
|
||
|
|
#ifdef __CLIP_W
|
||
|
|
in1 = line->v[0]->hw - line->v[0]->__CLIP_COORD;
|
||
|
|
in2 = line->v[1]->hw - line->v[1]->__CLIP_COORD;
|
||
|
|
#else
|
||
|
|
in1 = line->v[0]->__CLIP_COORD;
|
||
|
|
in2 = line->v[1]->__CLIP_COORD;
|
||
|
|
#endif
|
||
|
|
#endif
|
||
|
|
if (in1 < 0)
|
||
|
|
{
|
||
|
|
if (in2 < 0)
|
||
|
|
return 1;
|
||
|
|
Interpolate(pv, &outv, line->v[0], line->v[1],
|
||
|
|
__CLIP_FLAG, in1, in1 - in2);
|
||
|
|
*line->v[0] = outv;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
if (in2 < 0)
|
||
|
|
{
|
||
|
|
Interpolate(pv, &outv, line->v[0], line->v[1],
|
||
|
|
__CLIP_FLAG, in1, in1 - in2);
|
||
|
|
*line->v[1] = outv;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
#undef __CLIP_FLAG
|
||
|
|
#undef __CLIP_COORD
|
||
|
|
#undef __CLIP_NAME
|
||
|
|
#undef __CLIP_LINE_NAME
|
||
|
|
#undef __CLIP_W
|
||
|
|
#undef __CLIP_SIGN
|
||
|
|
#undef __CLIP_GBCOEF
|