From 4987faed561b9593885f7a86561995a197a6a3e2 Mon Sep 17 00:00:00 2001
From: jonathan santis <jonathan.wyss@santismail.ch>
Date: Tue, 22 Oct 2024 14:57:57 +0200
Subject: [PATCH] sdf

---
 main.zig | 56 +++++++++++++++++++++++++++-----------------------------
 1 file changed, 27 insertions(+), 29 deletions(-)

diff --git a/main.zig b/main.zig
index 2c80c58..63513ac 100644
--- a/main.zig
+++ b/main.zig
@@ -17,9 +17,9 @@ const Winsize = struct {
     ws_ypixel: c_ushort = 0,
 };
 const Point = struct {
-    x: u32,
-    y: u32,
-    z: u32,
+    x: i32,
+    y: i32,
+    z: i32,
 };
 const Vec3 = struct {
     a: Point,
@@ -136,11 +136,11 @@ fn fillBuffer() !void {
     };
     _ = vec;
     //triangle(vec);
-    _ = try bresenham(buffer, w, Point{ .x = 10, .y = 40, .z = 0 }, Point{ .x = 100, .y = 20, .z = 0 });
+    _ = try bresenham(buffer, w, Point{ .x = 10, .y = 40, .z = 0 }, Point{ .x = 30, .y = 10, .z = 0 });
     try file.writeAll(buffer);
 }
-fn pixel(buffer: []u8, w: Winsize, x: u64, y: u64, symbol: u21) !void {
-    const i = 4 * (x + y * w.ws_col);
+fn pixel(buffer: []u8, w: Winsize, x: i64, y: i64, symbol: u21) !void {
+    const i: usize = @intCast(4 * (x + y * w.ws_col));
     if (i < buffer.len) {
         const slice = buffer[i .. i + 4];
         print("slice:{u}\n", .{slice});
@@ -152,37 +152,35 @@ fn pixel(buffer: []u8, w: Winsize, x: u64, y: u64, symbol: u21) !void {
     }
 }
 fn bresenham(buf: []u8, w: Winsize, p1: Point, p2: Point) !void {
-    var x: u64 = p1.x;
-    var y: u64 = p1.y;
+    const x1: i32 = p1.x;
+    const y1: i32 = p1.y;
+    var x: i32 = 0;
+    var y: i32 = 0;
     const dx = (p2.x - p1.x);
-    const a: u32 = 20;
-    const b: u32 = 40;
-    var c1: i64 = 0;
-    c1 = a - b;
-    print("c:{}\n", .{c1});
-    print("p2: {} - {},{}", .{ p2.y, p1.y, p2.y - p1.y });
-    var dy: i64 = ((p2.y) - (p1.y));
+    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, '.');
-
-        if (dy > 0) {
-            er += dy;
-            if (2 * er >= dx) {
-                y += 1;
-                er -= dx;
-            }
-        } else if (dy < 0) {
-            er -= dy;
-            if (2 * er >= dx) {
-                y -= 1;
-                er += dx;
-            }
+        er += dy;
+        if (2 * er >= dx) {
+            y += 1;
+            er -= dx;
         }
     }
-    dy = 0;
 }
 
 //fn triangle(vec: Vec3) void {