dif fixes

main.zig

@@ -18,10 +18,16 @@ const Winsize = struct {
     ws_xpixel: c_ushort = 0,
     ws_ypixel: c_ushort = 0,
 };
+const Direction = struct {
+    x: i8 = 1,
+    y: i8 = 1,
+    z: i8 = 1,
+};
 const Point = struct {
     x: i32,
     y: i32,
     z: i32,
+    direction: Direction, //for movement state
 };
 const Vec3 = struct {
     a: Point,
@@ -119,10 +125,6 @@ fn fillBuffer() !void {
     var w = Winsize{};
     var i: u64 = 0;
     var buf = std.mem.zeroes([2]u8);
-    var d: i8 = 1;
-    var d2: i8 = 1;
-    var d3: i8 = -1;
-    var d4: i8 = -1;
 
     buf[0] = 0;
     w = try getTermDimension();
@@ -132,9 +134,9 @@ fn fillBuffer() !void {
     var buffer = try allocator.alloc(u8, w.ws_row * w.ws_col * 4); //utf-8 can be 4 bytes long
     defer allocator.free(buffer);
     var vec = Vec3{
-        .a = Point{ .x = 20, .y = 20, .z = 0 },
+        .a = Point{ .x = 20, .y = 20, .z = 0, .direction = .{ .x = 1, .y = 1, .z = 1 } },
-        .b = Point{ .x = 50, .y = 30, .z = 0 },
+        .b = Point{ .x = 50, .y = 30, .z = 0, .direction = .{ .x = 1, .y = 1, .z = 1 } },
-        .c = Point{ .x = 30, .y = 1, .z = 0 },
+        .c = Point{ .x = 30, .y = 1, .z = 0, .direction = .{ .x = 1, .y = 1, .z = 1 } },
     };
 
     while (true) {
@@ -148,46 +150,61 @@ fn fillBuffer() !void {
         try pixel(buffer, w, 5, 10, '\u{1F702}');
         try triangle(buffer, w, vec);
         //_ = try bresenham(buffer, w, Point{ .x = 10, .y = 10, .z = 0 }, Point{ .x = 30, .y = 12, .z = 0 });
-        // try file.writeAll(buffer);
-
-        if (vec.c.x < w.ws_col) {
-            vec.c.x += d;
-        }
-        if (vec.c.x == w.ws_col or vec.c.x == 0) {
-            d *= -1;
-            vec.c.x += d;
-        }
-        if (vec.a.y < w.ws_row) {
-            vec.a.y += d2;
-        }
-        if (vec.a.y == w.ws_row or vec.a.y == 0) {
-            d2 *= -1;
-            vec.a.y += d2;
-        }
-        if (vec.b.y < w.ws_row) {
-            vec.b.y += d3;
-        }
-        if (vec.b.y == w.ws_row or vec.b.y == 0) {
-            d3 *= -1;
-            vec.b.y += d3;
-        }
-        if (vec.b.x < w.ws_col) {
-            vec.b.x += d4;
-        }
-        if (vec.b.x == w.ws_col or vec.b.x == 0) {
-            d4 *= -1;
-            vec.b.x += d4;
-        }
 
         try triangle(buffer, w, vec);
         try out.print("\x1B[2J", .{});
-
+        bounce(w, &vec.a, 'x');
+        bounce(w, &vec.a, 'y');
+        bounce(w, &vec.b, 'x');
+        bounce(w, &vec.b, 'y');
+        bounce(w, &vec.c, 'x');
+        bounce(w, &vec.c, 'y');
         print("\x1b[45\x1b[37", .{});
         try out.print("{s}", .{buffer});
 
         _ = try stdin.readUntilDelimiterOrEof(&buf, '\n');
     }
 }
+fn bounce(w: Winsize, point: *Point, axis: u8) void {
+    var cor = &point.x;
+    var dir = &point.direction.x;
+    var upper = w.ws_col;
+
+    switch (axis) {
+        'x' => {
+            cor = &point.x;
+            upper = w.ws_col;
+            dir = &point.direction.x;
+        },
+        'y' => {
+            cor = &point.y;
+            upper = w.ws_row;
+            dir = &point.direction.y;
+        },
+        'X' => {
+            cor = &point.x;
+            upper = w.ws_col;
+            dir = &point.direction.y;
+            dir.* = -1;
+        },
+        'Y' => {
+            cor = &point.y;
+            upper = w.ws_row;
+            dir = &point.direction.y;
+            dir.* = -1;
+        },
+        else => {},
+    }
+
+    if (cor.* < upper) {
+        cor.* += dir.*;
+    }
+    if (cor.* >= upper or cor.* <= 0) {
+        dir.* *= -1;
+        cor.* += dir.*;
+    }
+}
+
 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) { //-1 ??