Add video demo

Makefile

@@ -23,7 +23,8 @@ STAGE_BIN=$(STAGE)/init \
 		  $(STAGE)/bin/mkdir \
 		  $(STAGE)/bin/netctl \
 		  $(STAGE)/bin/netmeow \
-		  $(STAGE)/bin/netdump
+		  $(STAGE)/bin/netdump \
+		  $(STAGE)/bin/video
 
 #		  $(STAGE)/bin/com \
 #		  $(STAGE)/bin/ase \

core/bin/video.c

@@ -0,0 +1,85 @@
+#include <ygg/video.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <assert.h>
+#include <signal.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <time.h>
+
+static int running = 1;
+
+static void signal_handler(int signum) {
+    running = 0;
+}
+
+int main(int argc, char **argv) {
+    struct ioc_vmode mode;
+    int fd = open("/dev/fb0", O_RDONLY, 0);
+    if (fd < 0) {
+        perror("open()");
+        return -1;
+    }
+
+    if (ioctl(fd, IOC_GETVMODE, &mode) != 0) {
+        perror("ioctl()");
+        goto end;
+    }
+
+    signal(SIGINT, signal_handler);
+
+    printf("Video mode: %dx%d\n", mode.width, mode.height);
+
+    size_t size = mode.width * mode.height * 4;
+    size = (size + 0xFFF) & ~0xFFF;
+    printf("%u bytes\n", size);
+
+    printf("You can exit by pressing ^C\n");
+    printf("Starting video in 3 secs\n");
+    usleep(3000000);
+
+    int no = 0;
+    if (ioctl(fd, IOC_FBCON, &no) != 0) {
+        perror("ioctl()");
+        goto  end;
+    }
+
+    uint32_t *data = mmap(NULL, size, 0, MAP_PRIVATE, fd, 0);
+    assert(data);
+
+    struct timeval tv;
+    int c = 0;
+    int s = 0;
+
+    while (running) {
+        usleep(10000);
+        gettimeofday(&tv, NULL);
+        if (s == 0) {
+            c += 2;
+        } else {
+            c -= 2;
+        }
+        if (c < 0) {
+            s = 0;
+            c = 0;
+        } else if (c >= 256) {
+            s = 1;
+            c = 255;
+        }
+        memset(data, c, size);
+    }
+
+    munmap(data, size);
+    no = 1;
+    if (ioctl(fd, IOC_FBCON, &no) != 0) {
+        perror("ioctl()");
+        goto  end;
+    }
+    puts2("\033[2J\033[1;1f");
+    printf("Goodbye\n");
+end:
+    close(fd);
+
+    return 0;
+}