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 import gamnit_ios is conditional(ios)
  27 import input_ios is conditional(ios)
  28
  29 redef class App
  30
  31         # Main `GamnitDisplay` initialized by `create_gamnit`
  32         var display: nullable GamnitDisplay = null
  33
  34         # Hook to setup the OpenGL context: compiling shaders, creating VBO, reloading textures, etc.
  35         #
  36         # The gamnit services redefine this method to prepare optimizations and more.
  37         # Clients may also refine this method to prepare custom OpenGL resources.
  38         fun create_gamnit do end
  39
  40         # Hook to prepare for recreating the OpenGL context
  41         #
  42         # Some gamnit services refine this method to reset caches before the
  43         # next call to `create_gamnit`.
  44         fun recreate_gamnit do end
  45
  46         # Create and set `self.display`
  47         fun create_display
  48         do
  49                 var display = new GamnitDisplay
  50                 display.setup
  51                 self.display = display
  52
  53                 # Print the current GL configuration, for debugging
  54                 print "GL vendor: {glGetString(gl_VENDOR)}"
  55                 print "GL renderer: {glGetString(gl_RENDERER)}"
  56                 print "GL version: {glGetString(gl_VERSION)}"
  57                 print "GLSL version: {glGetString(gl_SHADING_LANGUAGE_VERSION)}"
  58                 print "GL extensions: {glGetString(gl_EXTENSIONS)}"
  59                 print "GL max texture size: {glGetIntegerv(gl_MAX_TEXTURE_SIZE, 0)}"
  60         end
  61
  62         # Hook for client programs to setup the scene
  63         #
  64         # Refine this method to build the game world or the main menu,
  65         # creating instances of `Sprite` and `Actor` as needed.
  66         #
  67         # This method is called only once per execution of the program and it should
  68         # be considered as the entry point of most game logic.
  69         fun create_scene do end
  70
  71         # Core of the frame logic, executed only when the display is visible
  72         #
  73         # This method should be redefined by user modules to customize the behavior of the game.
  74         protected fun frame_core(display: GamnitDisplay) do end
  75
  76         # Full frame logic, executed even if the display is not visible
  77         #
  78         # This method wraps `frame_core` and other services to be executed in the main app loop.
  79         #
  80         # To customize the behavior on each turn, it is preferable to redefined `frame_core`.
  81         # Still, `frame_full` can be redefined with care for more control.
  82         protected fun frame_full
  83         do
  84                 var display = display
  85                 if display != null then frame_core(display)
  86
  87                 feed_events
  88         end
  89
  90         redef fun run
  91         do
  92                 # TODO manage exit condition
  93                 loop frame_full
  94         end
  95
  96         # Loop on available events and feed them back to the app
  97         #
  98         # The implementation varies per platform.
  99         private fun feed_events do end
 100
 101         # Hook to receive and respond to `event` triggered by the user or system
 102         #
 103         # Returns whether or not the event is used or intercepted.
 104         # If `true`, the event will not be processed further by the system.
 105         # Returns `false` to intercepts events like the back key on mobile devices.
 106         #
 107         # The instances passed as `event` may be freed (or overwritten),
 108         # right after this method returns. They should not be preserved.
 109         fun accept_event(event: InputEvent): Bool do return false
 110
 111         # The window has been resized by the user or system
 112         #
 113         # The framework handles resizing the viewport automatically.
 114         fun on_resize(display: GamnitDisplay) do end
 115 end
 116
 117 # Portable indirection to `glBindFramebuffer(gl_FRAMEBUFFER, fbo)`
 118 #
 119 # This is implemented differently on iOS.
 120 fun bind_screen_framebuffer(fbo: Int) do glBindFramebuffer(gl_FRAMEBUFFER, fbo)