From 5800f04eb0417c980fef2eddd78d8b60d19d0db5 Mon Sep 17 00:00:00 2001
From: gbc dev <gbc@localhost>
Date: Sat, 4 Jul 2026 22:12:57 +0200
Subject: terminal renderer (truecolor half-block), input, screenshot mode

---
 src/render.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 src/render.c

(limited to 'src/render.c')

diff --git a/src/render.c b/src/render.c
new file mode 100644
index 0000000..005fd71
--- /dev/null
+++ b/src/render.c
@@ -0,0 +1,112 @@
+#include "render.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <termios.h>
+#include <fcntl.h>
+
+#define UPPER "\xe2\x96\x80"   // ▀ U+2580
+
+static struct termios orig_termios;
+static bool raw_active = false;
+
+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);
+    atexit(term_restore);
+}
+
+// large reusable output buffer
+static char outbuf[SCREEN_W * (SCREEN_H/2) * 40 + 4096];
+
+void render_frame(GB *gb) {
+    PPU *p = &gb->ppu;
+    char *o = outbuf;
+    o += sprintf(o, "\x1b[H");
+    for (int y = 0; y < SCREEN_H; y += 2) {
+        int pr = -1, pg = -1, pb = -1;   // prev fg
+        int PR = -1, PG = -1, PB = -1;   // prev bg
+        for (int x = 0; x < SCREEN_W; x++) {
+            u8 *top = p->fb[y][x];
+            u8 *bot = p->fb[y+1][x];
+            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;
+        }
+        memcpy(o, "\x1b[0m\r\n", 6); o += 6;
+    }
+    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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