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                 print "GL max texture size: {glGetIntegerv(gl_MAX_TEXTURE_SIZE, 0)}"
  49         end
  50
  51         # Hook for client programs to setup the scene
  52         #
  53         # Refine this method to build the game world or the main menu,
  54         # creating instances of `Sprite` and `Actor` as needed.
  55         #
  56         # This method is called only once per execution of the program and it should
  57         # be considered as the entry point of most game logic.
  58         fun create_scene do end
  59
  60         # Core of the frame logic, executed only when the display is visible
  61         #
  62         # This method should be redefined by user modules to customize the behavior of the game.
  63         protected fun frame_core(display: GamnitDisplay) do end
  64
  65         # Full frame logic, executed even if the display is not visible
  66         #
  67         # This method wraps `frame_core` and other services to be executed in the main app loop.
  68         #
  69         # To customize the behavior on each turn, it is preferable to redefined `frame_core`.
  70         # Still, `frame_full` can be redefined with care for more control.
  71         protected fun frame_full
  72         do
  73                 var display = display
  74                 if display != null then frame_core(display)
  75
  76                 feed_events
  77         end
  78
  79         redef fun run
  80         do
  81                 # TODO manage exit condition
  82                 loop frame_full
  83         end
  84
  85         # Loop on available events and feed them back to the app
  86         #
  87         # The implementation varies per platform.
  88         private fun feed_events do end
  89
  90         # Hook to receive and respond to `event` triggered by the user or system
  91         #
  92         # Returns whether or not the event is used or intercepted.
  93         # If `true`, the event will not be processed further by the system.
  94         # Returns `false` to intercepts events like the back key on mobile devices.
  95         #
  96         # The instances passed as `event` may be freed (or overwritten),
  97         # right after this method returns. They should not be preserved.
  98         fun accept_event(event: InputEvent): Bool do return false
  99
 100         # The window has been resized by the user or system
 101         #
 102         # The framework handles resizing the viewport automatically.
 103         fun on_resize(display: GamnitDisplay) do end
 104 end
 105
 106 # Portable indirection to `glBindFramebuffer(gl_FRAMEBUFFER, fbo)`
 107 #
 108 # This is implemented differently on iOS.
 109 fun bind_screen_framebuffer(fbo: Int) do glBindFramebuffer(gl_FRAMEBUFFER, fbo)