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#include "render.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <signal.h>
#define UPPER "\xe2\x96\x80" // ▀ U+2580
static struct termios orig_termios;
static bool raw_active = false;
static void on_winch(int s);
void term_restore(void) {
if (raw_active) {
tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios);
raw_active = false;
}
// show cursor, leave alt screen, reset colors
printf("\x1b[0m\x1b[?25h\x1b[?1049l");
fflush(stdout);
}
void term_init(void) {
tcgetattr(STDIN_FILENO, &orig_termios);
struct termios raw = orig_termios;
raw.c_lflag &= ~(ECHO | ICANON | ISIG);
raw.c_iflag &= ~(IXON | ICRNL);
raw.c_cc[VMIN] = 0;
raw.c_cc[VTIME] = 0;
tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
raw_active = true;
// enter alt screen, hide cursor, clear
printf("\x1b[?1049h\x1b[?25l\x1b[2J\x1b[H");
fflush(stdout);
signal(SIGWINCH, on_winch);
render_force_full();
atexit(term_restore);
}
// large reusable output buffer
static char outbuf[SCREEN_W * (SCREEN_H/2) * 40 + 4096];
// previous frame's pixels, for inter-frame diffing
static u8 prev_fb[SCREEN_H][SCREEN_W][3];
static bool need_full = true; // force a complete repaint
static volatile sig_atomic_t resized = 0; // set by SIGWINCH
void render_force_full(void) { need_full = true; }
static void on_winch(int s) { (void)s; resized = 1; }
void render_frame(GB *gb) {
PPU *p = &gb->ppu;
char *o = outbuf;
if (resized) { resized = 0; need_full = true; o += sprintf(o, "\x1b[2J"); }
// Terminal SGR (color) state persists across cursor moves, so we can keep
// one fg/bg tracker for the whole frame even when we jump over unchanged
// cells. Reset each frame since we emit a final \x1b[0m.
int pr = -1, pg = -1, pb = -1; // last-emitted fg
int PR = -1, PG = -1, PB = -1; // last-emitted bg
int cur_row = -2, cur_col = -2; // terminal cell just written (0-indexed)
for (int y = 0; y < SCREEN_H; y += 2) {
int row = y / 2;
for (int x = 0; x < SCREEN_W; x++) {
u8 *top = p->fb[y][x];
u8 *bot = p->fb[y+1][x];
if (!need_full) {
u8 *pt = prev_fb[y][x], *pb2 = prev_fb[y+1][x];
if (top[0]==pt[0] && top[1]==pt[1] && top[2]==pt[2] &&
bot[0]==pb2[0] && bot[1]==pb2[1] && bot[2]==pb2[2])
continue; // cell unchanged -> skip
}
// reposition cursor only when we're not already right after the
// previously written cell
if (row != cur_row || x != cur_col + 1)
o += sprintf(o, "\x1b[%d;%dH", row + 1, x + 1);
if (top[0] != pr || top[1] != pg || top[2] != pb) {
o += sprintf(o, "\x1b[38;2;%d;%d;%dm", top[0], top[1], top[2]);
pr = top[0]; pg = top[1]; pb = top[2];
}
if (bot[0] != PR || bot[1] != PG || bot[2] != PB) {
o += sprintf(o, "\x1b[48;2;%d;%d;%dm", bot[0], bot[1], bot[2]);
PR = bot[0]; PG = bot[1]; PB = bot[2];
}
memcpy(o, UPPER, 3); o += 3;
cur_row = row; cur_col = x;
}
}
// status line: static text, only (re)draw on a full repaint
if (need_full) {
o += sprintf(o, "\x1b[0m\x1b[%d;1H\x1b[38;2;150;150;150m %.*s "
"[wasd/arrows] z:A x:B space:sel enter:start q:quit",
SCREEN_H/2 + 1, 15, gb->cart.title);
}
memcpy(prev_fb, p->fb, sizeof(prev_fb));
need_full = false;
if (o != outbuf) { // nothing changed -> write nothing
o += sprintf(o, "\x1b[0m");
fwrite(outbuf, 1, o - outbuf, stdout);
fflush(stdout);
}
}
// ---- input with decay-based "hold" emulation ----
static int hold[8]; // frames remaining for each BTN bit position
#define HOLD_FRAMES 4
static void press(int bit) {
for (int i = 0; i < 8; i++) if ((1 << i) == bit) hold[i] = HOLD_FRAMES;
}
bool input_poll(GB *gb) {
unsigned char buf[64];
int n = read(STDIN_FILENO, buf, sizeof(buf));
bool quit = false;
for (int i = 0; i < n; i++) {
unsigned char ch = buf[i];
if (ch == 0x1b && i + 2 < n && buf[i+1] == '[') {
switch (buf[i+2]) {
case 'A': press(BTN_UP); break;
case 'B': press(BTN_DOWN); break;
case 'C': press(BTN_RIGHT); break;
case 'D': press(BTN_LEFT); break;
}
i += 2;
continue;
}
switch (ch) {
case 'w': press(BTN_UP); break;
case 's': press(BTN_DOWN); break;
case 'a': press(BTN_LEFT); break;
case 'd': press(BTN_RIGHT); break;
case 'z': case 'j': press(BTN_A); break;
case 'x': case 'k': press(BTN_B); break;
case '\r': case '\n': press(BTN_START); break;
case ' ': press(BTN_SELECT); break;
case 'q': case 3: quit = true; break;
}
}
// build button state from decay counters
u8 b = 0;
for (int i = 0; i < 8; i++) {
if (hold[i] > 0) { hold[i]--; b |= (1 << i); }
}
gb->buttons = b;
if (b) gb_request_interrupt(gb, INT_JOYPAD);
return !quit;
}
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