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quakeforge/libs/video/renderer/sw/sw_raclip.c
Bill Currie 3103f400fd [sw] Clean up r_refdef and R_ViewChanged 
r_refdef is really meant for holding the various screen "constants" for
the software renderer rather than the more generic scene stuff. All the
fields referenced by the low level rendering code (especially assembly)
have been moved to the beginning of the struct (and nicely fit within 64
bytes). The other fields should be moved elsewhere, but not this commit.

On top of that, R_ViewChanged is much easier to read, and there are
fewer static globals.
2022-03-27 15:32:00 +09:00

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/*
r_aclip.c
clip routines for drawing Alias models directly to the screen
Copyright (C) 1996-1997 Id Software, Inc.
This program 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.
This program 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 this program; if not, write to:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "QF/render.h"
#include "d_local.h"
#include "r_internal.h"
#ifdef PIC
# undef USE_INTEL_ASM //XXX asm pic hack
#endif
static finalvert_t fv[2][8];
static auxvert_t av[8];
/*
R_Alias_clip_z
pfv0 is the unclipped vertex, pfv1 is the z-clipped vertex
*/
static void
R_Alias_clip_z (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
{
float scale;
auxvert_t *pav0, *pav1, avout;
pav0 = &av[pfv0 - &fv[0][0]];
pav1 = &av[pfv1 - &fv[0][0]];
if (pfv0->v[1] >= pfv1->v[1]) {
scale = (ALIAS_Z_CLIP_PLANE - pav0->fv[2]) /
(pav1->fv[2] - pav0->fv[2]);
avout.fv[0] = pav0->fv[0] + (pav1->fv[0] - pav0->fv[0]) * scale;
avout.fv[1] = pav0->fv[1] + (pav1->fv[1] - pav0->fv[1]) * scale;
avout.fv[2] = ALIAS_Z_CLIP_PLANE;
out->v[2] = pfv0->v[2] + (pfv1->v[2] - pfv0->v[2]) * scale;
out->v[3] = pfv0->v[3] + (pfv1->v[3] - pfv0->v[3]) * scale;
out->v[4] = pfv0->v[4] + (pfv1->v[4] - pfv0->v[4]) * scale;
} else {
scale = (ALIAS_Z_CLIP_PLANE - pav1->fv[2]) /
(pav0->fv[2] - pav1->fv[2]);
avout.fv[0] = pav1->fv[0] + (pav0->fv[0] - pav1->fv[0]) * scale;
avout.fv[1] = pav1->fv[1] + (pav0->fv[1] - pav1->fv[1]) * scale;
avout.fv[2] = ALIAS_Z_CLIP_PLANE;
out->v[2] = pfv1->v[2] + (pfv0->v[2] - pfv1->v[2]) * scale;
out->v[3] = pfv1->v[3] + (pfv0->v[3] - pfv1->v[3]) * scale;
out->v[4] = pfv1->v[4] + (pfv0->v[4] - pfv1->v[4]) * scale;
}
R_AliasProjectFinalVert (out, &avout);
if (out->v[0] < r_refdef.aliasvrectleft)
out->flags |= ALIAS_LEFT_CLIP;
if (out->v[1] < r_refdef.aliasvrecttop)
out->flags |= ALIAS_TOP_CLIP;
if (out->v[0] > r_refdef.aliasvrectright)
out->flags |= ALIAS_RIGHT_CLIP;
if (out->v[1] > r_refdef.aliasvrectbottom)
out->flags |= ALIAS_BOTTOM_CLIP;
}
#ifndef USE_INTEL_ASM
void
R_Alias_clip_left (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
{
float scale;
int i;
if (pfv0->v[1] >= pfv1->v[1]) {
scale = (float) (r_refdef.aliasvrectleft - pfv0->v[0]) /
(pfv1->v[0] - pfv0->v[0]);
for (i = 0; i < 6; i++)
out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i]) * scale + 0.5;
} else {
scale = (float) (r_refdef.aliasvrectleft - pfv1->v[0]) /
(pfv0->v[0] - pfv1->v[0]);
for (i = 0; i < 6; i++)
out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i]) * scale + 0.5;
}
}
void
R_Alias_clip_right (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
{
float scale;
int i;
if (pfv0->v[1] >= pfv1->v[1]) {
scale = (float) (r_refdef.aliasvrectright - pfv0->v[0]) /
(pfv1->v[0] - pfv0->v[0]);
for (i = 0; i < 6; i++)
out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i]) * scale + 0.5;
} else {
scale = (float) (r_refdef.aliasvrectright - pfv1->v[0]) /
(pfv0->v[0] - pfv1->v[0]);
for (i = 0; i < 6; i++)
out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i]) * scale + 0.5;
}
}
void
R_Alias_clip_top (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
{
float scale;
int i;
if (pfv0->v[1] >= pfv1->v[1]) {
scale = (float) (r_refdef.aliasvrecttop - pfv0->v[1]) /
(pfv1->v[1] - pfv0->v[1]);
for (i = 0; i < 6; i++)
out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i]) * scale + 0.5;
} else {
scale = (float) (r_refdef.aliasvrecttop - pfv1->v[1]) /
(pfv0->v[1] - pfv1->v[1]);
for (i = 0; i < 6; i++)
out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i]) * scale + 0.5;
}
}
void
R_Alias_clip_bottom (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
{
float scale;
int i;
if (pfv0->v[1] >= pfv1->v[1]) {
scale = (float) (r_refdef.aliasvrectbottom - pfv0->v[1]) /
(pfv1->v[1] - pfv0->v[1]);
for (i = 0; i < 6; i++)
out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i]) * scale + 0.5;
} else {
scale = (float) (r_refdef.aliasvrectbottom - pfv1->v[1]) /
(pfv0->v[1] - pfv1->v[1]);
for (i = 0; i < 6; i++)
out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i]) * scale + 0.5;
}
}
#endif
static int
R_AliasClip (finalvert_t *in, finalvert_t *out, int flag, int count,
void (*clip) (finalvert_t *pfv0, finalvert_t *pfv1,
finalvert_t *out))
{
int i, j, k;
int flags, oldflags;
j = count - 1;
k = 0;
for (i = 0; i < count; j = i, i++) {
oldflags = in[j].flags & flag;
flags = in[i].flags & flag;
if (flags && oldflags)
continue;
if (oldflags ^ flags) {
clip (&in[j], &in[i], &out[k]);
out[k].flags = 0;
if (out[k].v[0] < r_refdef.aliasvrectleft)
out[k].flags |= ALIAS_LEFT_CLIP;
if (out[k].v[1] < r_refdef.aliasvrecttop)
out[k].flags |= ALIAS_TOP_CLIP;
if (out[k].v[0] > r_refdef.aliasvrectright)
out[k].flags |= ALIAS_RIGHT_CLIP;
if (out[k].v[1] > r_refdef.aliasvrectbottom)
out[k].flags |= ALIAS_BOTTOM_CLIP;
k++;
}
if (!flags) {
out[k] = in[i];
k++;
}
}
return k;
}
void
R_AliasClipTriangle (mtriangle_t *ptri)
{
int i, k, pingpong;
mtriangle_t mtri;
unsigned int clipflags;
// copy vertexes and fix seam texture coordinates
if (ptri->facesfront) {
fv[0][0] = pfinalverts[ptri->vertindex[0]];
fv[0][1] = pfinalverts[ptri->vertindex[1]];
fv[0][2] = pfinalverts[ptri->vertindex[2]];
} else {
for (i = 0; i < 3; i++) {
fv[0][i] = pfinalverts[ptri->vertindex[i]];
if (!ptri->facesfront && (fv[0][i].flags & ALIAS_ONSEAM))
fv[0][i].v[2] += r_affinetridesc.seamfixupX16;
}
}
// clip
clipflags = fv[0][0].flags | fv[0][1].flags | fv[0][2].flags;
if (clipflags & ALIAS_Z_CLIP) {
for (i = 0; i < 3; i++)
av[i] = pauxverts[ptri->vertindex[i]];
k = R_AliasClip (fv[0], fv[1], ALIAS_Z_CLIP, 3, R_Alias_clip_z);
if (k == 0)
return;
pingpong = 1;
clipflags = fv[1][0].flags | fv[1][1].flags | fv[1][2].flags;
} else {
pingpong = 0;
k = 3;
}
if (clipflags & ALIAS_LEFT_CLIP) {
k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
ALIAS_LEFT_CLIP, k, R_Alias_clip_left);
if (k == 0)
return;
pingpong ^= 1;
}
if (clipflags & ALIAS_RIGHT_CLIP) {
k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
ALIAS_RIGHT_CLIP, k, R_Alias_clip_right);
if (k == 0)
return;
pingpong ^= 1;
}
if (clipflags & ALIAS_BOTTOM_CLIP) {
k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
ALIAS_BOTTOM_CLIP, k, R_Alias_clip_bottom);
if (k == 0)
return;
pingpong ^= 1;
}
if (clipflags & ALIAS_TOP_CLIP) {
k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
ALIAS_TOP_CLIP, k, R_Alias_clip_top);
if (k == 0)
return;
pingpong ^= 1;
}
for (i = 0; i < k; i++) {
if (fv[pingpong][i].v[0] < r_refdef.aliasvrectleft)
fv[pingpong][i].v[0] = r_refdef.aliasvrectleft;
else if (fv[pingpong][i].v[0] > r_refdef.aliasvrectright)
fv[pingpong][i].v[0] = r_refdef.aliasvrectright;
if (fv[pingpong][i].v[1] < r_refdef.aliasvrecttop)
fv[pingpong][i].v[1] = r_refdef.aliasvrecttop;
else if (fv[pingpong][i].v[1] > r_refdef.aliasvrectbottom)
fv[pingpong][i].v[1] = r_refdef.aliasvrectbottom;
fv[pingpong][i].flags = 0;
}
// draw triangles
mtri.facesfront = ptri->facesfront;
r_affinetridesc.ptriangles = &mtri;
r_affinetridesc.pfinalverts = fv[pingpong];
// FIXME: do all at once as trifan?
mtri.vertindex[0] = 0;
for (i = 1; i < k - 1; i++) {
mtri.vertindex[1] = i;
mtri.vertindex[2] = i + 1;
D_PolysetDraw ();
}
}
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