mirror of
https://github.com/w23/xash3d-fwgs
synced 2024-12-17 14:59:57 +01:00
324 lines
8.7 KiB
C
324 lines
8.7 KiB
C
/*
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Copyright (C) 1997-2001 Id Software, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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// r_aclip.c: clip routines for drawing Alias models directly to the screen
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#include "r_local.h"
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static finalvert_t fv[2][8];
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void R_AliasProjectAndClipTestFinalVert (finalvert_t *fv);
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void R_Alias_clip_top (finalvert_t *pfv0, finalvert_t *pfv1,
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finalvert_t *out);
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void R_Alias_clip_bottom (finalvert_t *pfv0, finalvert_t *pfv1,
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finalvert_t *out);
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void R_Alias_clip_left (finalvert_t *pfv0, finalvert_t *pfv1,
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finalvert_t *out);
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void R_Alias_clip_right (finalvert_t *pfv0, finalvert_t *pfv1,
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finalvert_t *out);
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/*
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================
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R_Alias_clip_z
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pfv0 is the unclipped vertex, pfv1 is the z-clipped vertex
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================
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*/
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void R_Alias_clip_z (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
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{
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float scale;
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scale = (ALIAS_Z_CLIP_PLANE - pfv0->xyz[2]) /
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(pfv1->xyz[2] - pfv0->xyz[2]);
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out->xyz[0] = pfv0->xyz[0] + (pfv1->xyz[0] - pfv0->xyz[0]) * scale;
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out->xyz[1] = pfv0->xyz[1] + (pfv1->xyz[1] - pfv0->xyz[1]) * scale;
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out->xyz[2] = ALIAS_Z_CLIP_PLANE;
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out->s = pfv0->s + (pfv1->s - pfv0->s) * scale;
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out->t = pfv0->t + (pfv1->t - pfv0->t) * scale;
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out->l = pfv0->l + (pfv1->l - pfv0->l) * scale;
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R_AliasProjectAndClipTestFinalVert (out);
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}
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#if !id386
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void R_Alias_clip_left (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
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{
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float scale;
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if (pfv0->v >= pfv1->v )
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{
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scale = (float)(RI.aliasvrect.x - pfv0->u) /
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(pfv1->u - pfv0->u);
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out->u = pfv0->u + ( pfv1->u - pfv0->u ) * scale + 0.5f;
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out->v = pfv0->v + ( pfv1->v - pfv0->v ) * scale + 0.5f;
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out->s = pfv0->s + ( pfv1->s - pfv0->s ) * scale + 0.5f;
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out->t = pfv0->t + ( pfv1->t - pfv0->t ) * scale + 0.5f;
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out->l = pfv0->l + ( pfv1->l - pfv0->l ) * scale + 0.5f;
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out->zi = pfv0->zi + ( pfv1->zi - pfv0->zi) * scale + 0.5f;
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}
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else
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{
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scale = (float)(RI.aliasvrect.x - pfv1->u) /
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(pfv0->u - pfv1->u);
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out->u = pfv1->u + ( pfv0->u - pfv1->u ) * scale + 0.5f;
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out->v = pfv1->v + ( pfv0->v - pfv1->v ) * scale + 0.5f;
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out->s = pfv1->s + ( pfv0->s - pfv1->s ) * scale + 0.5f;
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out->t = pfv1->t + ( pfv0->t - pfv1->t ) * scale + 0.5f;
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out->l = pfv1->l + ( pfv0->l - pfv1->l ) * scale + 0.5f;
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out->zi = pfv1->zi + ( pfv0->zi - pfv1->zi) * scale + 0.5f;
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}
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}
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void R_Alias_clip_right (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
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{
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float scale;
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if ( pfv0->v >= pfv1->v )
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{
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scale = (float)(RI.aliasvrectright - pfv0->u ) /
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(pfv1->u - pfv0->u );
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out->u = pfv0->u + ( pfv1->u - pfv0->u ) * scale + 0.5f;
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out->v = pfv0->v + ( pfv1->v - pfv0->v ) * scale + 0.5f;
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out->s = pfv0->s + ( pfv1->s - pfv0->s ) * scale + 0.5f;
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out->t = pfv0->t + ( pfv1->t - pfv0->t ) * scale + 0.5f;
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out->l = pfv0->l + ( pfv1->l - pfv0->l ) * scale + 0.5f;
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out->zi = pfv0->zi + ( pfv1->zi - pfv0->zi) * scale + 0.5f;
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}
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else
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{
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scale = (float)(RI.aliasvrectright - pfv1->u ) /
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(pfv0->u - pfv1->u );
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out->u = pfv1->u + ( pfv0->u - pfv1->u ) * scale + 0.5f;
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out->v = pfv1->v + ( pfv0->v - pfv1->v ) * scale + 0.5f;
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out->s = pfv1->s + ( pfv0->s - pfv1->s ) * scale + 0.5f;
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out->t = pfv1->t + ( pfv0->t - pfv1->t ) * scale + 0.5f;
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out->l = pfv1->l + ( pfv0->l - pfv1->l ) * scale + 0.5f;
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out->zi = pfv1->zi + ( pfv0->zi - pfv1->zi) * scale + 0.5f;
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}
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}
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void R_Alias_clip_top (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out)
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{
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float scale;
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if (pfv0->v >= pfv1->v)
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{
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scale = (float)(RI.aliasvrect.y - pfv0->v) /
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(pfv1->v - pfv0->v);
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out->u = pfv0->u + ( pfv1->u - pfv0->u ) * scale + 0.5f;
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out->v = pfv0->v + ( pfv1->v - pfv0->v ) * scale + 0.5f;
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out->s = pfv0->s + ( pfv1->s - pfv0->s ) * scale + 0.5f;
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out->t = pfv0->t + ( pfv1->t - pfv0->t ) * scale + 0.5f;
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out->l = pfv0->l + ( pfv1->l - pfv0->l ) * scale + 0.5f;
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out->zi = pfv0->zi + ( pfv1->zi - pfv0->zi) * scale + 0.5f;
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}
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else
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{
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scale = (float)(RI.aliasvrect.y - pfv1->v) /
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(pfv0->v - pfv1->v);
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out->u = pfv1->u + ( pfv0->u - pfv1->u ) * scale + 0.5f;
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out->v = pfv1->v + ( pfv0->v - pfv1->v ) * scale + 0.5f;
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out->s = pfv1->s + ( pfv0->s - pfv1->s ) * scale + 0.5f;
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out->t = pfv1->t + ( pfv0->t - pfv1->t ) * scale + 0.5f;
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out->l = pfv1->l + ( pfv0->l - pfv1->l ) * scale + 0.5f;
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out->zi = pfv1->zi + ( pfv0->zi - pfv1->zi) * scale + 0.5f;
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}
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}
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void R_Alias_clip_bottom (finalvert_t *pfv0, finalvert_t *pfv1,
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finalvert_t *out)
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{
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float scale;
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if (pfv0->v >= pfv1->v)
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{
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scale = (float)(RI.aliasvrectbottom - pfv0->v) /
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(pfv1->v - pfv0->v);
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out->u = pfv0->u + ( pfv1->u - pfv0->u ) * scale + 0.5f;
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out->v = pfv0->v + ( pfv1->v - pfv0->v ) * scale + 0.5f;
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out->s = pfv0->s + ( pfv1->s - pfv0->s ) * scale + 0.5f;
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out->t = pfv0->t + ( pfv1->t - pfv0->t ) * scale + 0.5f;
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out->l = pfv0->l + ( pfv1->l - pfv0->l ) * scale + 0.5f;
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out->zi = pfv0->zi + ( pfv1->zi - pfv0->zi) * scale + 0.5f;
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}
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else
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{
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scale = (float)(RI.aliasvrectbottom - pfv1->v) /
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(pfv0->v - pfv1->v);
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out->u = pfv1->u + ( pfv0->u - pfv1->u ) * scale + 0.5f;
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out->v = pfv1->v + ( pfv0->v - pfv1->v ) * scale + 0.5f;
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out->s = pfv1->s + ( pfv0->s - pfv1->s ) * scale + 0.5f;
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out->t = pfv1->t + ( pfv0->t - pfv1->t ) * scale + 0.5f;
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out->l = pfv1->l + ( pfv0->l - pfv1->l ) * scale + 0.5f;
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out->zi = pfv1->zi + ( pfv0->zi - pfv1->zi) * scale + 0.5f;
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}
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}
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#endif
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int R_AliasClip (finalvert_t *in, finalvert_t *out, int flag, int count,
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void(*clip)(finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) )
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{
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int i,j,k;
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int flags, oldflags;
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j = count-1;
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k = 0;
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for (i=0 ; i<count ; j = i, i++)
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{
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oldflags = in[j].flags & flag;
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flags = in[i].flags & flag;
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if (flags && oldflags)
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continue;
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if (oldflags ^ flags)
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{
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clip (&in[j], &in[i], &out[k]);
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out[k].flags = 0;
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if (out[k].u < RI.aliasvrect.x)
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out[k].flags |= ALIAS_LEFT_CLIP;
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if (out[k].v < RI.aliasvrect.y)
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out[k].flags |= ALIAS_TOP_CLIP;
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if (out[k].u > RI.aliasvrectright)
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out[k].flags |= ALIAS_RIGHT_CLIP;
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if (out[k].v > RI.aliasvrectbottom)
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out[k].flags |= ALIAS_BOTTOM_CLIP;
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k++;
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}
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if (!flags)
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{
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out[k] = in[i];
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k++;
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}
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}
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return k;
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}
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/*
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================
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R_AliasClipTriangle
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================
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*/
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void R_AliasClipTriangle (finalvert_t *index0, finalvert_t *index1, finalvert_t *index2)
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{
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int i, k, pingpong;
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unsigned clipflags;
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// copy vertexes and fix seam texture coordinates
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fv[0][0] = *index0;
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fv[0][1] = *index1;
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fv[0][2] = *index2;
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// clip
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clipflags = fv[0][0].flags | fv[0][1].flags | fv[0][2].flags;
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if (clipflags & ALIAS_Z_CLIP)
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{
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k = R_AliasClip (fv[0], fv[1], ALIAS_Z_CLIP, 3, R_Alias_clip_z);
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if (k == 0)
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return;
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pingpong = 1;
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clipflags = fv[1][0].flags | fv[1][1].flags | fv[1][2].flags;
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}
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else
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{
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pingpong = 0;
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k = 3;
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}
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if (clipflags & ALIAS_LEFT_CLIP)
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{
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k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
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ALIAS_LEFT_CLIP, k, R_Alias_clip_left);
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if (k == 0)
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return;
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pingpong ^= 1;
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}
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if (clipflags & ALIAS_RIGHT_CLIP)
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{
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k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
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ALIAS_RIGHT_CLIP, k, R_Alias_clip_right);
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if (k == 0)
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return;
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pingpong ^= 1;
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}
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if (clipflags & ALIAS_BOTTOM_CLIP)
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{
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k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
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ALIAS_BOTTOM_CLIP, k, R_Alias_clip_bottom);
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if (k == 0)
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return;
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pingpong ^= 1;
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}
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if (clipflags & ALIAS_TOP_CLIP)
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{
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k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1],
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ALIAS_TOP_CLIP, k, R_Alias_clip_top);
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if (k == 0)
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return;
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pingpong ^= 1;
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}
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for (i=0 ; i<k ; i++)
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{
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if (fv[pingpong][i].u < RI.aliasvrect.x)
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fv[pingpong][i].u = RI.aliasvrect.x;
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else if (fv[pingpong][i].u > RI.aliasvrectright)
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fv[pingpong][i].u = RI.aliasvrectright;
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if (fv[pingpong][i].v < RI.aliasvrect.y)
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fv[pingpong][i].v = RI.aliasvrect.y;
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else if (fv[pingpong][i].v > RI.aliasvrectbottom)
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fv[pingpong][i].v = RI.aliasvrectbottom;
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fv[pingpong][i].flags = 0;
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}
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// draw triangles
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for (i=1 ; i<k-1 ; i++)
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{
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aliastriangleparms.a = &fv[pingpong][0];
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aliastriangleparms.b = &fv[pingpong][i];
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aliastriangleparms.c = &fv[pingpong][i+1];
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R_DrawTriangle();
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}
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}
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