lib/mnit_android/android_assets.nit

   1 # This file is part of NIT (http://www.nitlanguage.org).
   2 #
   3 # Copyright 2012-2014 Alexis Laferrière <alexis.laf@xymus.net>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # Implements the `mnit::assets` services with a wraper around the filesystem
  18 # API provided by the Android ndk.
  19 #
  20 # This module relies heavily on 3 C libraries:
  21 # * The Android ndk
  22 # * zlib (which is included in the Android ndk)
  23 # * libpng which must be provided by the Nit compilation framework
  24 module android_assets is ldflags "-lz"
  25
  26 import mnit
  27 import android_app
  28
  29 in "C header" `{
  30         #include <png.h>
  31         #include <zlib.h>
  32 `}
  33
  34 in "C" `{
  35         void mnit_android_png_read_data(png_structp png_ptr,
  36                         png_bytep data, png_size_t length)
  37         {
  38                         struct AAsset *recv = png_get_io_ptr(png_ptr);
  39                         int read = AAsset_read(recv, data, length);
  40         }
  41         void mnit_android_png_error_fn(png_structp png_ptr,
  42                 png_const_charp error_msg)
  43         {
  44                         LOGW("libpng error: %s", error_msg);
  45         }
  46         void mnit_android_png_warning_fn(png_structp png_ptr,
  47                 png_const_charp warning_msg)
  48         {
  49                         LOGW("libpng warning: %s", warning_msg);
  50         }
  51 `}
  52
  53 extern class AndroidAsset in "C" `{struct AAsset*`}
  54
  55         fun read(count: Int): nullable String is extern import String.as nullable, NativeString.to_s `{
  56                 char *buffer = malloc(sizeof(char) * (count+1));
  57                 int read = AAsset_read(recv, buffer, count);
  58                 if (read != count)
  59                         return null_String();
  60                 else
  61                 {
  62                         buffer[count] = '\0';
  63                         return String_as_nullable(NativeString_to_s(buffer));
  64                 }
  65         `}
  66
  67         fun length: Int is extern `{
  68                 return AAsset_getLength(recv);
  69         `}
  70
  71         fun to_fd: Int is extern `{
  72                 off_t start;
  73                 off_t length;
  74                 int fd = AAsset_openFileDescriptor(recv, &start, &length);
  75                 return fd;
  76         `}
  77
  78         fun close is extern `{
  79                 AAsset_close(recv);
  80         `}
  81 end
  82
  83 redef class App
  84         redef fun try_loading_asset(path)
  85         do
  86                 var a = load_asset_from_apk(path)
  87                 if a != null then
  88                         if path.file_extension == "png" then
  89                                 var png = new Opengles1Image.from_android_asset(a)
  90                                 a.close
  91                                 return png
  92                         else if path.file_extension == "txt" then
  93                                 var len = a.length
  94                                 var txt = a.read(len)
  95                                 return txt
  96                         end
  97                 else
  98                         print "didn't get asset {path}"
  99                 end
 100
 101                 return null
 102         end
 103
 104         protected fun load_asset_from_apk(path: String): nullable AndroidAsset is extern import String.to_cstring, AndroidAsset.as nullable, native_app_glue  `{
 105                 struct android_app *native_app_glue = App_native_app_glue(recv);
 106                 struct AAsset* a = AAssetManager_open(native_app_glue->activity->assetManager, String_to_cstring(path), AASSET_MODE_BUFFER);
 107                 if (a == NULL)
 108                 {
 109                         LOGW("nit d g a");
 110                         return null_AndroidAsset();
 111                 }
 112                 else
 113                 {
 114                         return AndroidAsset_as_nullable(a);
 115                 }
 116         `}
 117 end
 118
 119 redef class Opengles1Image
 120         # Read a png from a zipped stream
 121         new from_android_asset(asset: AndroidAsset) is extern `{
 122                 struct mnit_opengles_Texture *recv = NULL;
 123
 124                 png_structp png_ptr = NULL;
 125                 png_infop info_ptr = NULL;
 126
 127                 png_uint_32 width, height;
 128                 int depth, color_type;
 129                 int has_alpha;
 130
 131                 unsigned int row_bytes;
 132                 png_bytepp row_pointers = NULL;
 133                 unsigned char *pixels = NULL;
 134                 unsigned int i;
 135
 136                 unsigned char sig[8];
 137                 int sig_read = AAsset_read(asset, sig, 8);
 138                 if (png_sig_cmp(sig, 0, sig_read)) {
 139                         LOGW("invalide png signature");
 140                         return NULL;
 141                 }
 142
 143                 png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 144                 if (png_ptr == NULL) {
 145                         LOGW("png_create_read_struct failed");
 146                         goto close_stream;
 147                 }
 148                 png_set_error_fn(png_ptr, NULL, mnit_android_png_error_fn, mnit_android_png_warning_fn);
 149
 150                 info_ptr = png_create_info_struct(png_ptr);
 151                 if (info_ptr == NULL) {
 152                         LOGW("png_create_info_struct failed");
 153                         goto close_png_ptr;
 154                 }
 155
 156                 if (setjmp(png_jmpbuf(png_ptr))) {
 157                         LOGW("reading png file failed");
 158                         goto close_png_ptr;
 159                 }
 160
 161                 png_set_read_fn(png_ptr, (void*)asset, mnit_android_png_read_data);
 162
 163                 png_set_sig_bytes(png_ptr, sig_read);
 164
 165                 png_read_info(png_ptr, info_ptr);
 166
 167                 png_get_IHDR(   png_ptr, info_ptr, &width, &height,
 168                                                 &depth, &color_type, NULL, NULL, NULL);
 169                 has_alpha = color_type & PNG_COLOR_MASK_ALPHA;
 170
 171                 // If we get gray and alpha only, standardize the format of the pixels.
 172                 // GA is not supported by OpenGL ES 1.
 173                 if (!(color_type & PNG_COLOR_MASK_COLOR)) {
 174                         png_set_gray_to_rgb(png_ptr);
 175                         png_set_palette_to_rgb(png_ptr);
 176                         png_read_update_info(png_ptr, info_ptr);
 177                 }
 178
 179                 LOGW("w: %i, h: %i", width, height);
 180
 181                 row_bytes = png_get_rowbytes(png_ptr, info_ptr);
 182                 pixels = malloc(row_bytes * height);
 183                 row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * height);
 184
 185                 for (i=0; i<height; i++)
 186                         row_pointers[i] = (png_byte*) malloc(row_bytes);
 187
 188                 png_read_image(png_ptr, row_pointers);
 189
 190                 for (i = 0; i < height; i++)
 191                         memcpy(pixels + (row_bytes*i),
 192                                         row_pointers[i], row_bytes);
 193
 194                 recv = mnit_opengles_load_image((const uint_least32_t *)pixels, width, height, has_alpha);
 195                 LOGW("OK");
 196
 197         close_png_ptr:
 198                 if (info_ptr != NULL)
 199                         png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 200                 else
 201                         png_destroy_read_struct(&png_ptr, NULL, NULL);
 202
 203                 if (pixels != NULL)
 204                         free(pixels);
 205
 206                 if (row_pointers != NULL) {
 207                         for (i=0; i<height; i++)
 208                                 free(row_pointers[i]);
 209                         free(row_pointers);
 210                 }
 211
 212         close_stream:
 213                 return recv;
 214         `}
 215 end