Initial commit

fb.c

@@ -0,0 +1,45 @@
+#include "fb.h"
+
+#include <linux/fb.h>
+#include <sys/mman.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+
+Framebuffer newFramebuffer(const char* device) {
+	Framebuffer fb;
+	
+	// Open the framebuffer file descriptor
+	fb.fd = open(device, O_RDWR);
+	assert(fb.fd >= 0 && "Invalid framebuffer device, please ensure your user is in the 'video' group.");
+
+	// Get information about framebuffer
+	ioctl(fb.fd, FBIOGET_VSCREENINFO, &fb.vinfo);
+
+	// Get size of screen for writing pixels in bounds
+	fb.screensize = fb.vinfo.xres * fb.vinfo.yres * fb.vinfo.bits_per_pixel / 8;
+
+	fb.data = mmap(0, fb.screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fb.fd, 0);
+
+	return fb;
+} 
+
+void writeColourToFramebuffer(Framebuffer* fb, Pixel pixel, Colour colour) {
+	int offset = (pixel.y * fb->vinfo.xres + pixel.x) * (fb->vinfo.bits_per_pixel / 8);
+
+	fb->data[offset + 0] = colour.red;
+	fb->data[offset + 1] = colour.green;
+	fb->data[offset + 2] = colour.blue;
+	fb->data[offset + 3] = colour.alpha;
+
+	
+	munmap(fb->data, fb->screensize);
+}
+
+void destroyFramebuffer(Framebuffer* fb) {
+	close(fb->fd);
+
+	// NOTE: Do not free fb->data, this is not memory owned by us.
+	// Will cause a segfault
+}