lib/gamnit/egl.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 # Use of EGL to implement Gamnit on GNU/Linux and Android
  16 module egl
  17
  18 import ::egl
  19
  20 import gamnit::display
  21
  22 redef class GamnitDisplay
  23
  24         # The EGL display
  25         var egl_display: EGLDisplay is noautoinit
  26
  27         # The EGL context
  28         var egl_context: EGLContext is noautoinit
  29
  30         # The EGL surface for the window
  31         var window_surface: EGLSurface is noautoinit
  32
  33         # The selected EGL configuration
  34         var egl_config: EGLConfig is noautoinit
  35
  36         # Setup the EGL display for the given `native_display`
  37         protected fun setup_egl_display(native_display: Pointer)
  38         do
  39                 var egl_display = new EGLDisplay(native_display)
  40                 assert egl_display.is_valid else print "new EGL display is not valid"
  41
  42                 egl_display.initialize
  43                 assert egl_display.is_valid else print "EGL initialize error: {egl_display.error}"
  44
  45                 self.egl_display = egl_display
  46         end
  47
  48         # Select an EGL config
  49         protected fun select_egl_config(red, green, blue, alpha, depth, stencil, sample: Int)
  50         do
  51                 var config_chooser = new EGLConfigChooser
  52                 config_chooser.renderable_type_egl
  53                 config_chooser.surface_type_egl
  54                 config_chooser.red_size = red
  55                 config_chooser.green_size = green
  56                 config_chooser.blue_size = blue
  57                 if alpha > 0 then config_chooser.alpha_size = alpha
  58                 if depth > 0 then config_chooser.depth_size = depth
  59                 if stencil > 0 then config_chooser.stencil_size = stencil
  60                 if sample > 0 then config_chooser.sample_buffers = sample
  61                 config_chooser.close
  62
  63                 var configs = config_chooser.choose(egl_display)
  64                 assert configs != null else print "Choosing EGL config failed: {egl_display.error}"
  65                 assert not configs.is_empty else print "Found no EGL config"
  66
  67                 if debug_gamnit then
  68                         print "EGL available configurations:"
  69                         for config in configs do
  70                                 var attribs = config.attribs(egl_display)
  71                                 print "* Conformant to: {attribs.conformant}"
  72                                 print "  Caveats: {attribs.caveat}"
  73                                 print "  Size of RGBA: {attribs.red_size} {attribs.green_size} {attribs.blue_size} {attribs.alpha_size}"
  74                                 print "  Buffer, depth, stencil: {attribs.buffer_size} {attribs.depth_size} {attribs.stencil_size}"
  75                         end
  76                 end
  77
  78                 # We use the first one, it is recommended
  79                 self.egl_config = configs.first
  80         end
  81
  82         # Setup the EGL context for the given `native_window`
  83         protected fun setup_egl_context(native_window: Pointer)
  84         do
  85                 var window_surface = egl_display.create_window_surface(egl_config, native_window, [0])
  86                 assert window_surface.is_ok else print "Creating EGL window surface failed: {egl_display.error}"
  87                 self.window_surface = window_surface
  88
  89                 egl_context = egl_display.create_context(egl_config)
  90                 assert egl_context.is_ok else print "Creating EGL context failed: {egl_display.error}"
  91
  92                 var make_current_res = egl_display.make_current(window_surface, window_surface, egl_context)
  93                 assert make_current_res else print "Creating EGL make current failed: {egl_display.error}"
  94
  95                 # TODO make the API selection configurable per platform
  96                 assert egl_bind_opengl_es_api else print "EGL bind API failed: {egl_display.error}"
  97         end
  98
  99         redef fun width do return window_surface.attribs(egl_display).width
 100
 101         redef fun height do return window_surface.attribs(egl_display).height
 102
 103         # Close the EGL context
 104         fun close_egl
 105         do
 106                 egl_display.make_current(new EGLSurface.none, new EGLSurface.none, new EGLContext.none)
 107                 egl_display.destroy_context(egl_context)
 108                 egl_display.destroy_surface(window_surface)
 109         end
 110
 111         redef fun flip
 112         do
 113                 assert glGetError == gl_NO_ERROR
 114
 115                 assert egl_display.is_valid
 116
 117                 egl_display.swap_buffers(window_surface)
 118         end
 119 end