main: --shot with --headless dumps final LCD on exit

Lets scripted runs feed stdin to the serial console AND capture the
resulting screen, e.g. printf 'ls\nexit\n' | gbc rom.gb --headless --shot 0 out.ppm
Previously --shot ran frames with no stdin, so anything waiting on input
(a shell) only showed its first prompt.

2 files changed, 9 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index 935c9e7..6d6379a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -135,6 +135,14 @@ int main(int argc, char **argv) {
             }
         }
         if (raw_tty) tcsetattr(STDIN_FILENO, TCSANOW, &saved_tio);
+        if (shot_frames >= 0) {          // --headless --shot FILE: dump final LCD
+            FILE *pf = fopen(shot_path, "wb");
+            fprintf(pf, "P6\n%d %d\n255\n", SCREEN_W, SCREEN_H);
+            for (int y = 0; y < SCREEN_H; y++)
+                for (int x = 0; x < SCREEN_W; x++)
+                    fwrite(gb->ppu.fb[y][x], 1, 3, pf);
+            fclose(pf);
+        }
         cart_free(&gb->cart); free(gb); return 0;
     }
 
diff --git a/src/ppu.c b/src/ppu.c
index 16ecc2e..381c306 100644
--- a/src/ppu.c
+++ b/src/ppu.c
@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include "ppu.h"
 #include <string.h>