ref: 2feac9be1d1bebe1a05a47c0adf0254228ca558d
dir: /d_scan.c/
#include "quakedef.h"
#include "r_fog.h"
int *r_turb_turb;
#include "d_scan.h"
/*
=============
D_WarpScreen
// this performs a slight compression of the screen at the same time as
// the sine warp, to keep the edges from wrapping
=============
*/
void D_WarpScreen (void)
{
static pixel_t *rowptr[MAXHEIGHT+(AMP2*2)];
static int column[MAXWIDTH+(AMP2*2)];
int w, h, u, v, *turb, *col;
pixel_t *dest, **row;
float wratio, hratio;
w = r_refdef.vrect.width;
h = r_refdef.vrect.height;
wratio = w / (float)scr_vrect.width;
hratio = h / (float)scr_vrect.height;
for(v = 0; v < scr_vrect.height+AMP2*2; v++)
rowptr[v] = dvars.viewbuffer + (r_refdef.vrect.y * dvars.width) + (dvars.width * (int)((float)v * hratio * h / (h + AMP2 * 2)));
for(u = 0; u < scr_vrect.width+AMP2*2; u++)
column[u] = r_refdef.vrect.x + (int)((float)u * wratio * w / (w + AMP2 * 2));
turb = intsintable + ((int)(cl.time*SPEED)&(CYCLE-1));
dest = vid.buffer + scr_vrect.y * vid.width + scr_vrect.x;
for(v = 0; v < scr_vrect.height; v++, dest += vid.width){
col = &column[turb[v]];
row = &rowptr[v];
for(u = 0; u < scr_vrect.width; u += 4){
dest[u+0] = row[turb[u+0]][col[u+0]];
dest[u+1] = row[turb[u+1]][col[u+1]];
dest[u+2] = row[turb[u+2]][col[u+2]];
dest[u+3] = row[turb[u+3]][col[u+3]];
}
}
}
static int
D_DrawSpanGetMax(float u, float v)
{
int s, m;
float us, vs;
s = 4;
us = u * (1<<16);
vs = v * (1<<16);
do{
m = 1 << (s+1);
if((int)(us*m) != 0 || (int)(vs*m) != 0)
return s;
s++;
}while(m < (int)dvars.width);
return s;
}
void
D_DrawSpans(espan_t *pspan, pixel_t *pbase, int width, byte alpha, int spanfunc)
{
int count, spancount, izistep, spancountminus1, spanshift, spanmax;
pixel_t *pdest;
uzint *pz, izi;
fixed16_t s, t, snext, tnext, sstep, tstep;
float sdivz, tdivz, zi, z, du, dv;
float sdivzstepu, tdivzstepu, zistepu;
fog_t fog;
bool fogged, fogenabled;
sstep = 0; // keep compiler happy
tstep = 0; // ditto
memset(&fog, 0, sizeof(fog));
spanshift = D_DrawSpanGetMax(dvars.zistepu, dvars.zistepv);
spanmax = 1 << spanshift;
sdivzstepu = dvars.sdivzstepu * spanmax;
tdivzstepu = dvars.tdivzstepu * spanmax;
zistepu = dvars.zistepu * spanmax;
izistep = (int)(dvars.zistepu * 0x8000 * 0x10000);
fogenabled = isfogged();
do{
pdest = dvars.viewbuffer + pspan->v*dvars.width + pspan->u;
pz = dvars.zbuffer + pspan->v*dvars.width + pspan->u;
zi = dvars.ziorigin + pspan->v*dvars.zistepv + pspan->u*dvars.zistepu;
izi = zi * 0x8000 * 0x10000;
count = pspan->count;
// calculate the initial s/z, t/z, 1/z, s, and t and clamp
du = pspan->u;
dv = pspan->v;
sdivz = dvars.sdivzorigin + dv*dvars.sdivzstepv + du*dvars.sdivzstepu;
tdivz = dvars.tdivzorigin + dv*dvars.tdivzstepv + du*dvars.tdivzstepu;
z = (float)(1<<16) / zi; // prescale to 16.16 fixed-point
s = (int)(sdivz * z) + dvars.sadjust;
s = clamp(s, 0, dvars.bbextents);
t = (int)(tdivz * z) + dvars.tadjust;
t = clamp(t, 0, dvars.bbextentt);
do{
// calculate s and t at the far end of the span
spancount = min(count, spanmax);
count -= spancount;
fogged = fogenabled && fogcalc(izi, izi + izistep*spancount, spancount, &fog);
if(count){
// calculate s/z, t/z, zi->fixed s and t at far end of span,
// calculate s and t steps across span by shifting
sdivz += sdivzstepu;
tdivz += tdivzstepu;
// prescale to 16.16 fixed-point
z = (float)(1<<16) / (zi + zistepu);
snext = (int)(sdivz * z) + dvars.sadjust;
// prevent round-off error on <0 steps from
// causing overstepping & running off the
// edge of the texture
snext = clamp(snext, spanmax, dvars.bbextents);
tnext = (int)(tdivz * z) + dvars.tadjust;
// guard against round-off error on <0 steps
tnext = clamp(tnext, spanmax, dvars.bbextentt);
sstep = (snext - s) >> spanshift;
tstep = (tnext - t) >> spanshift;
}else{
// calculate s/z, t/z, zi->fixed s and t at last pixel in span (so
// can't step off polygon), clamp, calculate s and t steps across
// span by division, biasing steps low so we don't run off the
// texture
spancountminus1 = spancount - 1;
sdivz += dvars.sdivzstepu * spancountminus1;
tdivz += dvars.tdivzstepu * spancountminus1;
// prescale to 16.16 fixed-point
z = (float)(1<<16) / (zi + dvars.zistepu * spancountminus1);
snext = (int)(sdivz * z) + dvars.sadjust;
// prevent round-off error on <0 steps from
// from causing overstepping & running off the
// edge of the texture
snext = clamp(snext, spanmax, dvars.bbextents);
tnext = (int)(tdivz * z) + dvars.tadjust;
// guard against round-off error on <0 steps
tnext = clamp(tnext, spanmax, dvars.bbextentt);
if(spancount > 1){
sstep = (snext - s) / spancountminus1;
tstep = (tnext - t) / spancountminus1;
}
}
pixel_t *pdest_ = pdest, *pbase_ = pbase;
uzint *pz_ = pz;
fog_t *fog_ = &fog;
int spancount_ = spancount, izi_ = izi;
if(fogged){
switch(spanfunc){
case SPAN_SOLID:
dospan_solid_f1(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, pz_, izi_, izistep, fog_);
break;
case SPAN_TURB:
dospan_turb_f1(pdest_, pbase_, s, t, sstep, tstep, spancount_, alpha, pz_, izi_, izistep, fog_);
break;
case SPAN_BLEND:
dospan_blend_f1(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, alpha, pz_, izi_, izistep, fog_);
break;
case SPAN_FENCE:
dospan_fence_f1(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, pz_, izi_, izistep, fog_);
break;
}
}else{
switch(spanfunc){
case SPAN_SOLID:
dospan_solid(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, pz_, izi_, izistep);
break;
case SPAN_TURB:
dospan_turb(pdest_, pbase_, s, t, sstep, tstep, spancount_, alpha, pz_, izi_, izistep);
break;
case SPAN_BLEND:
dospan_blend(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, alpha, pz_, izi_, izistep);
break;
case SPAN_FENCE:
dospan_fence(pdest_, pbase_, s, t, sstep, tstep, spancount_, width, pz_, izi_, izistep);
break;
}
}
pdest += spancount;
pz += spancount;
izi += izistep*spancount;
zi += zistepu;
s = snext;
t = tnext;
}while(count > 0);
}while((pspan = pspan->pnext) != nil);
}