From f834d31d46290115c9548da8f847b42f0351578d Mon Sep 17 00:00:00 2001
From: jonathan santis <jonathan.wyss@santismail.ch>
Date: Wed, 23 Oct 2024 13:51:33 +0200
Subject: [PATCH] Add bresenham variants

---
 main.zig | 61 +++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 23 deletions(-)

diff --git a/main.zig b/main.zig
index 63513ac..a8cf970 100644
--- a/main.zig
+++ b/main.zig
@@ -136,7 +136,11 @@ fn fillBuffer() !void {
     };
     _ = vec;
     //triangle(vec);
-    _ = try bresenham(buffer, w, Point{ .x = 10, .y = 40, .z = 0 }, Point{ .x = 30, .y = 10, .z = 0 });
+    _ = try bresenham(buffer, w, Point{ .x = 10, .y = 10, .z = 0 }, Point{ .x = 30, .y = 12, .z = 0 });
+    _ = try bresenham(buffer, w, Point{ .x = 10, .y = 10, .z = 0 }, Point{ .x = 30, .y = 28, .z = 0 });
+    _ = 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 file.writeAll(buffer);
 }
 fn pixel(buffer: []u8, w: Winsize, x: i64, y: i64, symbol: u21) !void {
@@ -152,33 +156,44 @@ fn pixel(buffer: []u8, w: Winsize, x: i64, y: i64, symbol: u21) !void {
     }
 }
 fn bresenham(buf: []u8, w: Winsize, p1: Point, p2: Point) !void {
-    const x1: i32 = p1.x;
-    const y1: i32 = p1.y;
-    var x: i32 = 0;
-    var y: i32 = 0;
+    var x: i32 = p1.x;
+    var y: i32 = p1.y;
+    //var x: i32 = 0;
+    //var y: i32 = 0;
     const dx = (p2.x - p1.x);
     print("p2: {} - {},{}\n", .{ p2.y, p1.y, p2.y - p1.y });
     const dy: i64 = (p2.y - p1.y);
     //const slope = dx/dy;
     var er: i64 = 0;
-
-    if (dy > 0 and dy <= dx) {
-        x = x1;
-        y = y1;
-    }
-    if (dy < 0 and @abs(dy) > dx) {
-        print("octant2\n", .{});
-        x = y1;
-        y = x1;
-    }
-
-    while (x <= p2.x) : (x += 1) {
-        print("[bresenham]x:{},y:{},er:{},dx:{},dy:{}\n", .{ x, y, er, dx, dy });
-        _ = try pixel(buf, w, x, y, '.');
-        er += dy;
-        if (2 * er >= dx) {
-            y += 1;
-            er -= dx;
+    if (dx >= dy and dy > 0) {
+        while (x <= p2.x) : (x += 1) {
+            print("[bresenham]x:{},y:{},er:{},dx:{},dy:{}\n", .{ x, y, er, dx, dy });
+            _ = try pixel(buf, w, x, y, '.');
+            er += dy;
+            if (2 * er >= dx) {
+                y += 1;
+                er -= dx;
+            }
+        }
+    } else if (dx < dy and dy > 0) {
+        while (y <= p2.y) : (y += 1) {
+            print("[bresenham2]x:{},y:{},er:{},dx:{},dy:{}\n", .{ x, y, er, dx, dy });
+            _ = try pixel(buf, w, x, y, ',');
+            er += dx;
+            if (2 * er >= dy) {
+                x += 1;
+                er -= dy;
+            }
+        }
+    } else if (@abs(dy) < dx and dy < 0) {
+        while (x <= p2.x) : (x += 1) {
+            print("[bresenham3]x:{},y:{},er:{},dx:{},dy:{}\n", .{ x, y, er, dx, dy });
+            _ = try pixel(buf, w, x, y, 'x');
+            er -= dy;
+            if (2 * er >= dx) {
+                y -= 1;
+                er -= dx;
+            }
         }
     }
 }