ref: 83d8a24215ddf66ee64fc4704151571b2e952685
dir: /sys/src/games/gb/ppu.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"
u8int ppustate, ppuy;
u32int pic[PICW*PICH*3];
ulong hblclock, rendclock;
jmp_buf mainjmp, renderjmp;
static int cyc, done, ppux, ppux0;
extern int prish;
extern u32int white;
Var ppuvars[] = {VAR(ppustate), VAR(ppuy), VAR(hblclock), VAR(rendclock), {nil, 0, 0}};
#define ryield() {if(setjmp(renderjmp) == 0) longjmp(mainjmp, 1);}
#define myield() {if(setjmp(mainjmp) == 0) longjmp(renderjmp, 1);}
typedef struct sprite sprite;
struct sprite {
u8int dy, x, t;
u8int fetched, pal;
u16int chr;
};
enum {
SPRPRI = 0x80,
SPRYFL = 0x40,
SPRXFL = 0x20,
SPRPAL = 0x10,
SPRBANK = 0x08,
TILCOL0 = 0x01,
TILPRI = 0x02,
TILSPR = 0x04,
};
sprite spr[10], *sprm;
void
ppurender(void)
{
int x, y, i, n, m, win;
u16int ta, ca, chr;
u8int tile, attr, pali;
u32int sr[8], *picp;
#define eat(nc) if(cyc <= nc){for(i = 0; i < nc; i++) if(--cyc == 0) ryield();} else cyc -= nc;
ryield();
attr = 0;
for(;;){
eat(6*2);
m = 168 + (reg[SCX] & 7);
win = 0;
if((reg[LCDC] & WINEN) != 0 && ppuy >= reg[WY] && reg[WX] <= 166)
if(reg[WX] == 0)
m = 7;
else if(reg[WX] == 166)
m = 0;
else{
m = reg[WX] + (reg[SCX] & 7) + 1;
win = -1;
}
ppux = 0;
ppux0 = 0;
picp = pic + ppuy * PICW * scale;
y = ppuy + reg[SCY] << 1 & 14;
ta = 0x1800 | reg[LCDC] << 7 & 0x400 | ppuy + reg[SCY] << 2 & 0x3e0 | reg[SCX] >> 3;
x = -(reg[SCX] & 7);
restart:
do{
tile = vram[ta];
if((mode & COL) != 0)
attr = vram[8192 + ta];
if((reg[LCDC] & BGTILE) != 0)
ca = (tile << 4) + y;
else
ca = 0x1000 + ((s32int)(tile << 24) >> 20) + y;
if((attr & 0x40) != 0)
ca ^= 14;
ca |= (attr & 8) << 10;
chr = vram[ca] << 8 | vram[ca+1];
pali = attr << 2 & 0x1c;
if((attr & 0x20) == 0)
for(i = 0; i < 8; i++){
sr[i] = pal[pali | chr >> 15 | chr >> 6 & 2] | ((chr & 0x8080) == 0) << prish;
chr <<= 1;
}
else
for(i = 0; i < 8; i++){
sr[i] = pal[pali | chr << 1 & 2 | chr >> 8 & 1] | ((chr & 0x0101) == 0) << prish;
chr >>= 1;
}
if((attr & 0x80) != 0)
for(i = 0; i < 8; i++)
sr[i] |= 2 << prish;
if((reg[LCDC] & BGEN) == 0 && (mode & COL) == 0 && ((mode & CGB) != 0 || win == 0))
for(i = 0; i < 8; i++)
sr[i] = white;
if(cyc <= 2*8){
for(i = 0; i < 2*8; i++)
if(--cyc == 0)
ryield();
y = ppuy + reg[SCY] << 1 & 14;
ta = 0x1800 | reg[LCDC] << 7 & 0x400 | ppuy + reg[SCY] << 2 & 0x3e0 | ta & 0x1f;
}else
cyc -= 2*8;
m -= 8;
n = m < 8 ? m : 8;
if((ta & 0x1f) == 0x1f)
ta &= ~0x1f;
else
ta++;
for(i = 0; i < n; i++, x++)
if(x >= 0)
picp[x] = sr[i];
ppux = x;
}while(m > 8);
if(win == -1){
win = 1;
ta = 0x1800 | reg[LCDC] << 4 & 0x400 | ppuy - reg[WY] << 2 & 0x3e0;
y = ppuy - reg[WY] << 1 & 14;
cyc += 2;
m = 175 - reg[WX];
goto restart;
}
done = 1;
ryield();
}
}
void
oamsearch(void)
{
u8int *p;
sprite *q;
int y0, sy;
u8int t, tn;
u8int *chrp;
y0 = ppuy + 16;
sy = (reg[LCDC] & SPR16) != 0 ? 16 : 8;
sprm = spr;
if((reg[LCDC] & SPREN) == 0)
return;
for(p = oam; p < oam + 160; p += 4){
if((u8int)(y0 - p[0]) >= sy)
continue;
if((mode & COL) == 0){
for(q = spr; q < sprm; q++)
if(q->x > p[1]){
if(sprm != spr + 10){
memmove(q + 1, q, (sprm - q) * sizeof(sprite));
sprm++;
}else
memmove(q + 1, q, (sprm - 1 - q) * sizeof(sprite));
goto found;
}
if(q == spr + 10)
continue;
sprm++;
found:;
}else
q = sprm++;
q->dy = y0 - p[0];
q->x = p[1];
q->t = t = p[3];
if((t & SPRYFL) != 0)
q->dy ^= sy - 1;
tn = p[2];
if(sy == 16)
tn = tn & ~1 | q->dy >> 3;
chrp = vram + (tn << 4 | q->dy << 1 & 14);
if((mode & COL) != 0){
chrp += t << 10 & 0x2000;
q->pal = 0x20 | t << 2 & 0x1c;
}else
q->pal = 4 + (t >> 2 & 4);
q->chr = chrp[0] << 8 | chrp[1];
if(p[1] < 8)
if((t & SPRXFL) != 0)
q->chr >>= 8 - p[1];
else
q->chr <<= 8 - p[1];
q->fetched = 0;
if((mode & COL) != 0 && sprm == spr + 10)
break;
}
}
void
sprites(void)
{
sprite *q;
u8int attr;
u32int *picp;
int x, x1;
u16int chr;
picp = pic + ppuy * PICW * scale;
for(q = spr; q < sprm; q++){
if(q->x <= ppux0 || q->x >= ppux + 8)
continue;
x = q->x - 8;
if(x < ppux0) x = ppux0;
x1 = q->x;
if(x1 > ppux) x1 = ppux;
for(; x < x1; x++){
attr = picp[x] >> prish;
chr = q->chr;
if((chr & ((q->t & SPRXFL) != 0 ? 0x0101 : 0x8080)) != 0 && (attr & TILSPR) == 0 &&
((mode & COL) != 0 && (reg[LCDC] & BGPRI) == 0 ||
(attr & TILPRI) == 0 && ((q->t & SPRPRI) == 0 || (attr & TILCOL0) != 0)))
if((q->t & SPRXFL) == 0)
picp[x] = pal[q->pal | chr >> 15 | chr >> 6 & 2] | TILSPR << prish;
else
picp[x] = pal[q->pal | chr << 1 & 2 | chr >> 8 & 1] | TILSPR << prish;
if((q->t & SPRXFL) != 0)
q->chr >>= 1;
else
q->chr <<= 1;
}
}
ppux0 = ppux;
}
void
ppusync(void)
{
if(ppustate != 3)
return;
cyc = clock - rendclock;
if(cyc != 0)
myield();
sprites();
rendclock = clock;
}
int
linelen(void)
{
int t;
t = 174 + (reg[SCX] & 7);
if((reg[LCDC] & WINEN) != 0 && ppuy >= reg[WY] && reg[WX] < 166)
if(reg[WX] == 0)
t += 7;
else
t += 6;
return t*2;
}
static void
lineexpand(void)
{
u32int *picp, *p, *q, l;
int i, s;
s = scale;
picp = pic + ppuy * PICW * s;
p = picp + PICW;
q = picp + PICW * scale;
for(i = PICW; --i >= 0; ){
l = *--p;
*--q = l;
*--q = l;
if(scale == 3)
*--q = l;
}
}
void
hblanktick(void *)
{
extern Event evhblank;
int t;
switch(ppustate){
case 0:
hblclock = clock + evhblank.time;
if(++ppuy == 144){
ppustate = 1;
if((reg[STAT] & IRQM1) != 0)
reg[IF] |= IRQLCDS;
addevent(&evhblank, 456*2);
reg[IF] |= IRQVBL;
flush();
}else{
ppustate = 2;
if((reg[STAT] & IRQM2) != 0)
reg[IF] |= IRQLCDS;
addevent(&evhblank, 80*2);
}
if((reg[STAT] & IRQLYC) != 0 && ppuy == reg[LYC])
reg[IF] |= IRQLCDS;
break;
case 1:
hblclock = clock + evhblank.time;
if(++ppuy == 154){
ppuy = 0;
ppustate = 2;
if((reg[STAT] & IRQM2) != 0)
reg[IF] |= IRQLCDS;
addevent(&evhblank, 80*2);
}else
addevent(&evhblank, 456*2);
if((reg[STAT] & IRQLYC) != 0 && ppuy == reg[LYC])
reg[IF] |= IRQLCDS;
break;
case 2:
oamsearch();
rendclock = clock + evhblank.time;
ppustate = 3;
addevent(&evhblank, linelen());
break;
case 3:
ppusync();
if(!done) print("not done?!\n");
done = 0;
if(scale > 1)
lineexpand();
ppustate = 0;
if((reg[STAT] & IRQM0) != 0)
reg[IF] |= IRQLCDS;
t = hblclock + 456 * 2 - clock;
addevent(&evhblank, t < 0 ? 456 * 2 : t);
if(dma < 0)
dma = 1;
break;
}
}
void
ppuinit(void)
{
static char ppustack[4096];
renderjmp[JMPBUFPC] = (uintptr)ppurender;
renderjmp[JMPBUFSP] = (uintptr)(ppustack + sizeof(ppustack) - 64);
myield();
}