warzone2100/lib/ivis_common/pieclip.c

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/*
This file is part of Warzone 2100.
Copyright (C) 1999-2004 Eidos Interactive
Copyright (C) 2005-2007 Warzone Resurrection Project
Warzone 2100 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
Warzone 2100 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Warzone 2100; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "pieclip.h"
#include "ivi.h"
static UDWORD videoBufferDepth = 32, videoBufferWidth = 640, videoBufferHeight = 480;
extern iSurface *psRendSurface;
BOOL pie_SetVideoBufferDepth(UDWORD depth)
{
videoBufferDepth = depth;
return(TRUE);
}
BOOL pie_SetVideoBufferWidth(UDWORD width)
{
videoBufferWidth = width;
return(TRUE);
}
BOOL pie_SetVideoBufferHeight(UDWORD height)
{
videoBufferHeight = height;
return(TRUE);
}
UDWORD pie_GetVideoBufferDepth(void)
{
return(videoBufferDepth);
}
UDWORD pie_GetVideoBufferWidth(void)
{
return(videoBufferWidth);
}
UDWORD pie_GetVideoBufferHeight(void)
{
return(videoBufferHeight);
}
void pie_Set2DClip(int x0, int y0, int x1, int y1)
{
psRendSurface->clip.left = x0;
psRendSurface->clip.top = y0;
psRendSurface->clip.right = x1;
psRendSurface->clip.bottom = y1;
}
static void pie_ClipUV(PIEVERTEX *s1, PIEVERTEX *s2, PIEVERTEX *clip, Sint32 t)
{
clip->u = s1->u + ((t * (s2->u - s1->u)) >> iV_DIVSHIFT);
clip->v = s1->v + ((t * (s2->v - s1->v)) >> iV_DIVSHIFT);
clip->z = s1->z + ((t * (s2->z - s1->z)) >> iV_DIVSHIFT);
clip->light.byte.r = s1->light.byte.r + ((t * (s2->light.byte.r - s1->light.byte.r)) >> iV_DIVSHIFT);
clip->light.byte.g = s1->light.byte.g + ((t * (s2->light.byte.g - s1->light.byte.g)) >> iV_DIVSHIFT);
clip->light.byte.b = s1->light.byte.b + ((t * (s2->light.byte.b - s1->light.byte.b)) >> iV_DIVSHIFT);
clip->light.byte.a = s1->light.byte.a + ((t * (s2->light.byte.a - s1->light.byte.a)) >> iV_DIVSHIFT);
}
static int pie_ClipXT(PIEVERTEX *s1, PIEVERTEX *s2, PIEVERTEX *clip)
{
int n = 1, dx;
Sint32 t;
if (s2->x >= s1->x)
{
if (s1->x < psRendSurface->clip.left)
{
if (s2->x <= psRendSurface->clip.left)
return 0;
dx = s2->x - s1->x;
if (dx != 0)
{
clip->y = s1->y + (s2->y - s1->y) * (psRendSurface->clip.left - s1->x) / dx;
}
else
{
clip->y = s1->y;
}
clip->x = psRendSurface->clip.left;
// clip uv
t = ((clip->x - s1->x) << iV_DIVSHIFT) / dx;
pie_ClipUV(s1, s2, clip, t);
}
else
{
*clip = *s1;
}
if (s2->x > psRendSurface->clip.right)
{
if (s1->x > psRendSurface->clip.right)
return 0;
clip++;
dx = s2->x - s1->x;
if (dx != 0)
{
clip->y = s2->y - (s2->y - s1->y) * (s2->x - psRendSurface->clip.right) / dx;
}
else
{
clip->y = s2->y;
}
clip->x = psRendSurface->clip.right;
// clip uv
t = ((clip->x - s1->x) << iV_DIVSHIFT) / dx;
pie_ClipUV(s1, s2, clip, t);
n = 2;
}
return n;
}
else
{
if (s1->x > psRendSurface->clip.right)
{
if (s2->x >= psRendSurface->clip.right)
return 0;
dx = s1->x - s2->x;
if (dx != 0)
{
clip->y = s1->y - (s1->y - s2->y) * (s1->x - psRendSurface->clip.right) / dx;
}
else
{
clip->y = s1->y;
}
clip->x = psRendSurface->clip.right;
// clip uv
t = ((clip->x - s1->x) << iV_DIVSHIFT) / dx;
pie_ClipUV(s1, s2, clip, t);
}
else
{
*clip = *s1;
}
if (s2->x < psRendSurface->clip.left)
{
if (s1->x < psRendSurface->clip.left)
return 0;
clip++;
dx = s1->x - s2->x;
if (dx != 0)
{
clip->y = s2->y + (s1->y - s2->y) * (psRendSurface->clip.left - s2->x) / dx;
}
else
{
clip->y = s2->y;
}
clip->x = psRendSurface->clip.left;
// clip uv
t = ((clip->x - s1->x)<<iV_DIVSHIFT) / dx;
pie_ClipUV(s1, s2, clip, t);
n = 2;
}
return n;
}
}
static int pie_ClipYT(PIEVERTEX *s1, PIEVERTEX *s2, PIEVERTEX *clip)
{
int n = 1, dy;
Sint32 t;
if (s2->y >= s1->y)
{
if (s1->y < psRendSurface->clip.top)
{
if (s2->y <= psRendSurface->clip.top)
return 0;
dy = s2->y - s1->y;
if (dy != 0)
{
clip->x = s1->x + (s2->x - s1->x) * (psRendSurface->clip.top - s1->y) / dy;
}
else
{
clip->x = s1->x;
}
clip->y = psRendSurface->clip.top;
// clip uv
t = ((clip->y - s1->y) << iV_DIVSHIFT) / dy;
pie_ClipUV(s1, s2, clip, t);
}
else
{
*clip = *s1;
}
if (s2->y > psRendSurface->clip.bottom)
{
if (s1->y > psRendSurface->clip.bottom)
{
return 0;
}
clip++;
dy = s2->y - s1->y;
if (dy != 0)
{
clip->x = s2->x - (s2->x - s1->x) * (s2->y - psRendSurface->clip.bottom) / dy;
}
else
{
clip->x = s2->x;
}
clip->y = psRendSurface->clip.bottom;
t = ((clip->y - s1->y) << iV_DIVSHIFT) / dy;
pie_ClipUV(s1, s2, clip, t);
n = 2;
}
return n;
}
else
{
if (s1->y > psRendSurface->clip.bottom)
{
if (s2->y >= psRendSurface->clip.bottom)
return 0;
dy = s1->y - s2->y;
if (dy != 0)
{
clip->x = s1->x - (s1->x - s2->x) * (s1->y - psRendSurface->clip.bottom) / dy;
}
else
{
clip->x = s1->x;
}
clip->y = psRendSurface->clip.bottom;
// clip uv
t = ((clip->y - s1->y) << iV_DIVSHIFT) / dy;
pie_ClipUV(s1, s2, clip, t);
}
else
{
*clip = *s1;
}
if (s2->y < psRendSurface->clip.top)
{
if (s1->y < psRendSurface->clip.top)
{
return 0;
}
clip++;
dy = s1->y - s2->y;
if (dy != 0)
{
clip->x = s2->x + (s1->x - s2->x) * (psRendSurface->clip.top - s2->y) / dy;
}
else
{
clip->x = s2->x;
}
clip->y = psRendSurface->clip.top;
t = ((clip->y - s1->y) << iV_DIVSHIFT) / dy;
pie_ClipUV(s1, s2, clip, t);
n = 2;
}
return n;
}
}
int pie_ClipTextured(int npoints, PIEVERTEX *points, PIEVERTEX *clip)
{
static PIEVERTEX xclip[iV_POLY_MAX_POINTS+4];
PIEVERTEX *p0, *p1;
int n1, n, i;
p0 = &points[0];
p1 = &points[1];
for (i = 0, n1 = 0; i < npoints; i++, p0++, p1++)
{
if (i == (npoints-1))
p1 = &points[0];
// FIXME MAGIC
if ((p0->x == 1<<15) || (p0->y == -1<<15))//check for invalid points jps19aug97
return 0;
n1 += pie_ClipXT(p0, p1, &xclip[n1]);
}
p0 = &xclip[0];
p1 = &xclip[1];
for (i = 0, n = 0; i < n1; p0++, p1++, i++)
{
if (i == (n1-1))
p1 = &xclip[0];
n += pie_ClipYT(p0, p1, &clip[n]);
}
return n;
}
#ifdef NEVER_USED_ANYWHERE
// I leave this around just for potential inspirational purposes. - Per
//*************************************************************************
/* Alex - much faster tri clipper - won't clip owt else tho' */
int pie_ClipTexturedTriangleFast(PIEVERTEX *v1, PIEVERTEX *v2, PIEVERTEX *v3, PIEVERTEX *clipped)
{
static PIEVERTEX xClip[iV_POLY_MAX_POINTS+4]; // plus 4 hopefully is limit?
static PIEVERTEX *p0,*p1;
UDWORD numPreY,numAll;
UDWORD i;
numPreY = 0;
if( (v1->x > LONG_TEST) || (v1->y > LONG_TEST) )
{
/* bomb out for out of range points */
return(0);
}
numPreY += pie_ClipXT(v1, v2, &xClip[numPreY]);
if( (v2->x > LONG_TEST) || (v2->y > LONG_TEST) )
{
/* bomb out for out of range points */
return(0);
}
numPreY += pie_ClipXT(v2, v3, &xClip[numPreY]);
if( (v3->x > LONG_TEST) || (v3->y > LONG_TEST) )
{
/* bomb out for out of range points */
return(0);
}
numPreY += pie_ClipXT(v3, v1, &xClip[numPreY]);
/* We've now clipped against x axis - now for Y */
p0 = &xClip[0];
p1 = &xClip[1];
for (i = 0, numAll = 0; i <n umPreY; p0++, p1++, i++) {
if (i == (numPreY-1))
p1 = &xClip[0];
numAll += pie_ClipYT(p0, p1, &clipped[numAll]);
}
return numAll;
}
#endif