1 files changed, 5 insertions, 1 deletions
diff --git a/framebuffer.c b/framebuffer.c
index 32c0f0f..ce48f35 100644
--- a/framebuffer.c
+++ b/framebuffer.c
@@ -73,7 +73,11 @@ void fb_put(Framebuffer fb, size_t row, size_t col, Pixel pixel) {
 }
 
 void fb_vert_line(Framebuffer fb, size_t x, size_t y1, size_t y2, Pixel pixel) {
-    assert(y2 >= y1);
+    if (y2 < y1) {
+        y2 ^= y1;
+        y1 ^= y2;
+        y2 ^= y1;
+    };
 
     for (size_t y = y1; y <= y2; y++) {
         fb.fb[y][x] = pixel;