From ae9afbc93728f3896b2b19634c1b6b03dc08e04f Mon Sep 17 00:00:00 2001
From: jonathan santis <jonathan.wyss@santismail.ch>
Date: Wed, 23 Oct 2024 14:37:15 +0200
Subject: [PATCH] add 4th octant

---
 main.zig | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/main.zig b/main.zig
index a8cf970..705a949 100644
--- a/main.zig
+++ b/main.zig
@@ -141,6 +141,7 @@ fn fillBuffer() !void {
     _ = try bresenham(buffer, w, Point{ .x = 10, .y = 10, .z = 0 }, Point{ .x = 30, .y = 30, .z = 0 });
     _ = try bresenham(buffer, w, Point{ .x = 10, .y = 10, .z = 0 }, Point{ .x = 30, .y = 40, .z = 0 });
     _ = try bresenham(buffer, w, Point{ .x = 30, .y = 30, .z = 0 }, Point{ .x = 60, .y = 10, .z = 0 });
+    _ = try bresenham(buffer, w, Point{ .x = 60, .y = 30, .z = 0 }, Point{ .x = 70, .y = 5, .z = 0 });
     try file.writeAll(buffer);
 }
 fn pixel(buffer: []u8, w: Winsize, x: i64, y: i64, symbol: u21) !void {
@@ -195,6 +196,16 @@ fn bresenham(buf: []u8, w: Winsize, p1: Point, p2: Point) !void {
                 er -= dx;
             }
         }
+    } else if (@abs(dy) > dx and dy < 0) {
+        while (y >= p2.y) : (y -= 1) {
+            print("[bresenham4]x:{},y:{},er:{},dx:{},dy:{}\n", .{ x, y, er, dx, dy });
+            _ = try pixel(buf, w, x, y, '4');
+            er += dx;
+            if (2 * er >= dy) {
+                x += 1;
+                er += dy;
+            }
+        }
     }
 }