lib/gamnit/camera_control.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # Simple camera control for user, as the method `accept_scroll_and_zoom`
  16 module camera_control
  17
  18 import gamnit
  19 import cameras
  20
  21 import camera_control_linux is conditional(linux)
  22 import camera_control_android is conditional(android)
  23
  24 redef class EulerCamera
  25         # Zoom and scroll this camera from user input
  26         #
  27         # Scrolling is accomplished by moving the camera on the XY plane and
  28         # zooming by moving it on the Z axis.
  29         #
  30         # This method has distinct implementations per platform.
  31         # On desktop computers, the mouse wheel changes the zoom level, and
  32         # holding down the middle mouse button scrolls the camera.
  33         # On Android, a two finger pinch and slide gesture zoom and scroll.
  34         #
  35         # Returns `true` if the event is used.
  36         #
  37         # Should be called from `App::accept_event` before accepting pointer events:
  38         #
  39         # ~~~nitish
  40         # redef class App
  41         #     redef fun accept_event(event)
  42         #     do
  43         #         if world_camera.accept_scroll_and_zoom(event) then return true
  44         #
  45         #         # Handle other events...
  46         #         return false
  47         #     end
  48         # end
  49         # ~~~
  50         fun accept_scroll_and_zoom(event: InputEvent): Bool do return false
  51 end