From 4ee5a2d4868082c9c1f44ba67dd006756de9ad2c Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Mon, 5 Feb 2018 14:47:19 -0500
Subject: Double-buffer gfb frontend

Still not vsync (seems like a newer DRM-fbdev implementation handles
FBIO_WAITFORVSYNC but my kernel doesn't), but avoids flicker from
clearing to black for each frame.
---
 bin/gfb.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/bin/gfb.c b/bin/gfb.c
index e64efee5..9925cc12 100644
--- a/bin/gfb.c
+++ b/bin/gfb.c
@@ -19,6 +19,7 @@
 #include <linux/fb.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sysexits.h>
@@ -75,8 +76,10 @@ int main(int argc, char *argv[]) {
     error = tcsetattr(STDERR_FILENO, TCSADRAIN, &term);
     if (error) err(EX_IOERR, "tcsetattr");
 
+    uint32_t back[info.xres * info.yres];
     for (;;) {
-        draw(buf, info.xres, info.yres);
+        draw(back, info.xres, info.yres);
+        memcpy(buf, back, size);
 
         char in;
         ssize_t len = read(STDERR_FILENO, &in, 1);
-- 
cgit 1.4.1