Working on framebuffer graphics.

1 files changed, 66 insertions, 0 deletions

diff --git a/sofbcode.c b/sofbcode.c
new file mode 100644
index 0000000..e4b9d3d
--- /dev/null
+++ b/sofbcode.c
@@ -0,0 +1,66 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <sys/mman.h>
+
+int main()
+{
+        int fbfd = 0;
+        struct fb_var_screeninfo vinfo;
+        struct fb_fix_screeninfo finfo;
+        long int screensize = 0;
+         char *fbp = 0;
+        int x = 0, y = 0;
+        long int location = 0;
+        int count ;
+
+        /* Open the file for reading and writing */
+        fbfd = open("/dev/fb0", O_RDWR);
+        if (!fbfd) {
+                printf("Error: cannot open framebuffer device.\n");
+                exit(1);
+        }
+        printf("The framebuffer device was opened successfully.\n");
+     /* Get fixed screen information */
+        if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
+               printf("Error reading fixed information.\n");
+                exit(2);
+        }
+
+        /* Get variable screen information */
+        if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
+                printf("Error reading variable information.\n");
+                exit(3);
+        }
+
+        /* Figure out the size of the screen in bytes */
+        screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;
+        printf("\nScreen size is %d",screensize);
+        printf("\nVinfo.bpp = %d",vinfo.bits_per_pixel);
+
+        /* Map the device to memory */
+        fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,fbfd, 0);
+        if ((int)fbp == -1) {
+                printf("Error: failed to map framebuffer device to memory.\n");
+                exit(4);
+        }
+         printf("The framebuffer device was mapped to memory successfully.\n");
+
+
+        x = 100; y = 100; /* Where we are going to put the pixel */
+
+        /* Figure out where in memory to put the pixel */
+        location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) + (y+vinfo.yoffset) * finfo.line_length;
+        for(count = 1 ;count < 100 ;count++)
+        {
+                *(fbp + location) = 255;    /* Some blue */
+                *(fbp + location + count) = 0; /* A little green */
+                *(fbp + location + count + 1) = 0; /* A lot of red */
+                *(fbp + location + count + 2) = 0; /* No transparency */
+        }
+        munmap(fbp, screensize);
+        close(fbfd);
+        return 0;
+}