From 3fbd1d35eb8807e73b28ce843edeaa37f6da1080 Mon Sep 17 00:00:00 2001
From: OverloadedOrama <35376950+OverloadedOrama@users.noreply.github.com>
Date: Sun, 9 Feb 2020 02:16:14 +0200
Subject: [PATCH] The camera now zooms at the mouse's position.

---
 Changelog.md              |  1 +
 Scripts/CameraMovement.gd | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index 759b3f628..3b7346240 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Major changes to alpha blending behavior. The alpha values now get added/blended together instead of just replacing the pixel with the new value.
 - Replaced some OS alerts with a custom made error dialog.
 - Made the zooming smoother, is toggleable in Preferences whether to keep the new zooming or the old one.
+- The camera now zooms at the mouse's position.
 - Made the "X" button on the custom brushes a little smaller.
 - The color picker will now have a small white triangle on the top left of the color preview if at least one of its RGB values are above 1 in Raw mode. (Added automatically because of the Godot 3.2 update)
 - You can now toggle the visibility of hidden items on and off in the file dialogs. (Added automatically because of the Godot 3.2 update)
diff --git a/Scripts/CameraMovement.gd b/Scripts/CameraMovement.gd
index 0567f1e89..f2c1b5945 100644
--- a/Scripts/CameraMovement.gd
+++ b/Scripts/CameraMovement.gd
@@ -4,6 +4,7 @@ var tween : Tween
 var zoom_min := Vector2(0.005, 0.005)
 var zoom_max := Vector2.ONE
 var viewport_container : ViewportContainer
+var mouse_pos := Vector2.ZERO
 var drag := false
 
 func _ready() -> void:
@@ -12,7 +13,7 @@ func _ready() -> void:
 	add_child(tween)
 
 func _input(event : InputEvent) -> void:
-	var mouse_pos := viewport_container.get_local_mouse_position()
+	mouse_pos = viewport_container.get_local_mouse_position()
 	var viewport_size := viewport_container.rect_size
 	if event.is_action_pressed("middle_mouse") || event.is_action_pressed("space"):
 		drag = true
@@ -29,22 +30,26 @@ func _input(event : InputEvent) -> void:
 
 # Zoom Camera
 func zoom_camera(dir : int) -> void:
+	var viewport_size := viewport_container.rect_size
 	if Global.smooth_zoom:
 		var zoom_margin = zoom * dir / 5
-		if zoom + zoom_margin > zoom_min:
-			tween.interpolate_property(self, "zoom", zoom, zoom + zoom_margin, 0.05, Tween.TRANS_LINEAR, Tween.EASE_IN)
+		var new_zoom = zoom + zoom_margin
+		if new_zoom > zoom_min && new_zoom < zoom_max:
+			var new_offset = offset + (-0.5 * viewport_size + mouse_pos) * (zoom - new_zoom)
+			tween.interpolate_property(self, "zoom", zoom, new_zoom, 0.05, Tween.TRANS_LINEAR, Tween.EASE_IN)
+			tween.interpolate_property(self, "offset", offset, new_offset, 0.05, Tween.TRANS_LINEAR, Tween.EASE_IN)
 			tween.start()
 
-		if zoom > zoom_max:
-			tween.stop_all()
-			zoom = zoom_max
-
 	else:
+		var prev_zoom := zoom
 		var zoom_margin = zoom * dir / 10
 		if zoom + zoom_margin > zoom_min:
 			zoom += zoom_margin
 
 		if zoom > zoom_max:
 			zoom = zoom_max
+
+		offset = offset + (-0.5 * viewport_size + mouse_pos) * (prev_zoom - zoom)
+
 	if name == "Camera2D":
 		Global.zoom_level_label.text = str(round(100 / Global.camera.zoom.x)) + " %"