From 4e123c94ed70b23c4922afb512a76d16af2b50bc Mon Sep 17 00:00:00 2001
From: =?utf8?q?Alexis=20Laferri=C3=A8re?= <alexis.laf@xymus.net>
Date: Wed, 5 Apr 2017 15:05:45 -0400
Subject: [PATCH] gamnit: intro `camera_control` an abstraction of
 `accept_two_fingers_motion`
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Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
---
 lib/gamnit/camera_control.nit                      |   51 ++++++++++++++++++++
 ...ngers_motion.nit => camera_control_android.nit} |   29 ++---------
 lib/gamnit/flat.nit                                |    3 +-
 3 files changed, 56 insertions(+), 27 deletions(-)
 create mode 100644 lib/gamnit/camera_control.nit
 rename lib/gamnit/{android_two_fingers_motion.nit => camera_control_android.nit} (79%)

diff --git a/lib/gamnit/camera_control.nit b/lib/gamnit/camera_control.nit
new file mode 100644
index 0000000..af5bedd
--- /dev/null
+++ b/lib/gamnit/camera_control.nit
@@ -0,0 +1,51 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Simple camera control for user, as the method `accept_scroll_and_zoom`
+module camera_control
+
+import gamnit
+import cameras
+
+import camera_control_linux is conditional(linux)
+import camera_control_android is conditional(android)
+
+redef class EulerCamera
+	# Zoom and scroll this camera from user input
+	#
+	# Scrolling is accomplished by moving the camera on the XY plane and
+	# zooming by moving it on the Z axis.
+	#
+	# This method has distinct implementations per platform.
+	# On desktop computers, the mouse wheel changes the zoom level, and
+	# holding down the middle mouse button scrolls the camera.
+	# On Android, a two finger pinch and slide gesture zoom and scroll.
+	#
+	# Returns `true` if the event is used.
+	#
+	# Should be called from `App::accept_event` before accepting pointer events:
+	#
+	# ~~~nitish
+	# redef class App
+	#     redef fun accept_event(event)
+	#     do
+	#         if world_camera.accept_scroll_and_zoom(event) then return true
+	#
+	#         # Handle other events...
+	#         return false
+	#     end
+	# end
+	# ~~~
+	fun accept_scroll_and_zoom(event: InputEvent): Bool do return false
+end
diff --git a/lib/gamnit/android_two_fingers_motion.nit b/lib/gamnit/camera_control_android.nit
similarity index 79%
rename from lib/gamnit/android_two_fingers_motion.nit
rename to lib/gamnit/camera_control_android.nit
index b8329ef..6461c29 100644
--- a/lib/gamnit/android_two_fingers_motion.nit
+++ b/lib/gamnit/camera_control_android.nit
@@ -12,16 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Two fingers camera manipulation, scroll and pinch to zoom
-#
-# Provides the main service `EulerCamera::accept_two_fingers_motion`.
-module android_two_fingers_motion
-
-# TODO add an abstraction when another platform supports it
+# Two fingers camera manipulation, pinch to zoom and slide to scroll
+module camera_control_android
 
-import gamnit
-import cameras
 import android
+import camera_control
 
 redef class EulerCamera
 	# Smoothened history of pointers in the current motion event
@@ -30,23 +25,7 @@ redef class EulerCamera
 	# Start time of the current motion event
 	private var last_motion_start: Int = -1
 
-	# Move and zoom (set `position`) from a two finger pinch and slide option
-	#
-	# Returns `true` if the event is intercepted.
-	#
-	# Should be called from `App::accept_event` before accepting pointer events:
-	#
-	# ~~~nitish
-	# redef class App
-	#     redef fun accept_event(event)
-	#     do
-	#         if world_camera.accept_two_fingers_motion(event) then return true
-	#
-	#         # Handle other events...
-	#     end
-	# end
-	# ~~~
-	fun accept_two_fingers_motion(event: InputEvent): Bool
+	redef fun accept_scroll_and_zoom(event)
 	do
 		if not event isa AndroidMotionEvent then return false
 
diff --git a/lib/gamnit/flat.nit b/lib/gamnit/flat.nit
index d5cb28e..c9935d8 100644
--- a/lib/gamnit/flat.nit
+++ b/lib/gamnit/flat.nit
@@ -42,8 +42,7 @@ import performance_analysis
 import gamnit
 import gamnit::cameras
 import gamnit::limit_fps
-
-import android_two_fingers_motion is conditional(android)
+import gamnit::camera_control
 
 # Draw a `texture` at `center`
 #
-- 
1.7.9.5