From 64bd8ee5306abf8f4b636ba92d00a6c1c8a02a66 Mon Sep 17 00:00:00 2001
From: Franz Dietrich <dietrich@teilgedanken.de>
Date: Sun, 19 Oct 2025 14:19:00 +0200
Subject: [PATCH] flip the direction of y now y increases upwards

---
 turtle-lib/src/builders.rs  | 2 +-
 turtle-lib/src/execution.rs | 3 ++-
 turtle-lib/src/tweening.rs  | 3 ++-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/turtle-lib/src/builders.rs b/turtle-lib/src/builders.rs
index 9fb48c2..bdcf84e 100644
--- a/turtle-lib/src/builders.rs
+++ b/turtle-lib/src/builders.rs
@@ -615,7 +615,7 @@ impl TurtlePlan {
     /// Coordinates are in screen space:
     /// - `(0, 0)` is at the center
     /// - Positive x goes right
-    /// - Positive y goes down
+    /// - Positive y goes up
     ///
     /// # Examples
     ///
diff --git a/turtle-lib/src/execution.rs b/turtle-lib/src/execution.rs
index 3b068c8..6eab70f 100644
--- a/turtle-lib/src/execution.rs
+++ b/turtle-lib/src/execution.rs
@@ -247,7 +247,8 @@ pub fn execute_command(command: &TurtleCommand, state: &mut Turtle) {
 
         TurtleCommand::Goto(coord) => {
             let start = state.params.position;
-            state.params.position = *coord;
+            // Flip Y coordinate: turtle graphics uses Y+ = up, but Macroquad uses Y+ = down
+            state.params.position = vec2(coord.x, -coord.y);
 
             if state.params.pen_down {
                 // Draw line segment with round caps
diff --git a/turtle-lib/src/tweening.rs b/turtle-lib/src/tweening.rs
index 4896735..e39396f 100644
--- a/turtle-lib/src/tweening.rs
+++ b/turtle-lib/src/tweening.rs
@@ -400,7 +400,8 @@ impl TweenController {
                 });
             }
             TurtleCommand::Goto(coord) => {
-                target.position = *coord;
+                // Flip Y coordinate: turtle graphics uses Y+ = up, but Macroquad uses Y+ = down
+                target.position = vec2(coord.x, -coord.y);
             }
             TurtleCommand::SetHeading(heading) => {
                 target.heading = normalize_angle(*heading);