lib/gamnit/gamnit.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 # Game and multimedia framework for Nit
  16 module gamnit
  17
  18 import app
  19
  20 import display
  21 import textures
  22 import programs
  23
  24 import gamnit_android is conditional(android)
  25 import gamnit_linux is conditional(linux)
  26
  27 redef class App
  28
  29         # Main `GamnitDisplay` initialized by `create_gamnit`
  30         var display: nullable GamnitDisplay = null
  31
  32         # Hook to setup the OpenGL context: compiling shaders, creating VBO, reloading textures, etc.
  33         #
  34         # The gamnit services redefine this method to prepare optimizations and more.
  35         # Clients may also refine this method to prepare custom OpenGL resources.
  36         fun create_gamnit
  37         do
  38                 var display = new GamnitDisplay
  39                 display.setup
  40                 self.display = display
  41
  42                 # Print the current GL configuration, for debugging
  43                 print "GL vendor: {glGetString(gl_VENDOR)}"
  44                 print "GL renderer: {glGetString(gl_RENDERER)}"
  45                 print "GL version: {glGetString(gl_VERSION)}"
  46                 print "GLSL version: {glGetString(gl_SHADING_LANGUAGE_VERSION)}"
  47                 print "GL extensions: {glGetString(gl_EXTENSIONS)}"
  48         end
  49
  50         # Hook for client programs to setup the scene
  51         #
  52         # Refine this method to build the game world or the main menu,
  53         # creating instances of `Sprite` and `Actor` as needed.
  54         #
  55         # This method is called only once per execution of the program and it should
  56         # be considered as the entry point of most game logic.
  57         fun create_scene do end
  58
  59         # Core of the frame logic, executed only when the display is visible
  60         #
  61         # This method should be redefined by user modules to customize the behavior of the game.
  62         protected fun frame_core(display: GamnitDisplay) do end
  63
  64         # Full frame logic, executed even if the display is not visible
  65         #
  66         # This method wraps `frame_core` and other services to be executed in the main app loop.
  67         #
  68         # To customize the behavior on each turn, it is preferable to redefined `frame_core`.
  69         # Still, `frame_full` can be redefined with care for more control.
  70         protected fun frame_full
  71         do
  72                 var display = display
  73                 if display != null then frame_core(display)
  74
  75                 feed_events
  76         end
  77
  78         redef fun run
  79         do
  80                 # TODO manage exit condition
  81                 loop frame_full
  82         end
  83
  84         # Loop on available events and feed them back to the app
  85         #
  86         # The implementation varies per platform.
  87         private fun feed_events do end
  88
  89         # Hook to receive and respond to `event` triggered by the user or system
  90         #
  91         # Returns whether or not the event is used or intercepted.
  92         # If `true`, the event will not be processed further by the system.
  93         # Returns `false` to intercepts events like the back key on mobile devices.
  94         #
  95         # The instances passed as `event` may be freed (or overwritten),
  96         # right after this method returns. They should not be preserved.
  97         fun accept_event(event: InputEvent): Bool do return false
  98
  99         # The window has been resized by the user or system
 100         #
 101         # The framework handles resizing the viewport automatically.
 102         fun on_resize(display: GamnitDisplay) do end
 103 end