lib/mnit: expand images to the nearest power of 2 for OpenGL ES 1.0

[nit.git] / lib / mnit_android / android_assets.nit

diff --git a/lib/mnit_android/android_assets.nit b/lib/mnit_android/android_assets.nit
index 8f61c90..d1ee104 100644 (file)
--- a/lib/mnit_android/android_assets.nit
+++ b/lib/mnit_android/android_assets.nit
@@ -86,7 +86,7 @@ redef class App
                var a = load_asset_from_apk(path)
                if a != null then
                        if path.file_extension == "png" then
-                               var png = new Opengles1Image.from_android_asset(a)      
+                               var png = new Opengles1Image.from_android_asset(a)
                                a.close
                                return png
                        else if path.file_extension == "txt" then
@@ -118,7 +118,7 @@ end
 
 redef class Opengles1Image
        # Read a png from a zipped stream
-       new from_android_asset(asset: AndroidAsset) is extern `{
+       new from_android_asset(asset: AndroidAsset) import Int.next_pow `{
                struct mnit_opengles_Texture *recv = NULL;
 
                png_structp png_ptr = NULL;
@@ -133,13 +133,16 @@ redef class Opengles1Image
                unsigned char *pixels = NULL;
                unsigned int i;
 
+               png_uint_32 width_pow2, height_pow2;
+               unsigned int row_bytes_pow2;
+
                unsigned char sig[8];
                int sig_read = AAsset_read(asset, sig, 8);
                if (png_sig_cmp(sig, 0, sig_read)) {
                        LOGW("invalide png signature");
                        return NULL;
                }
-               
+
                png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
                if (png_ptr == NULL) {
                        LOGW("png_create_read_struct failed");
@@ -176,11 +179,16 @@ redef class Opengles1Image
                        png_read_update_info(png_ptr, info_ptr);
                }
 
-               LOGW("w: %i, h: %i", width, height);
+               width_pow2 = Int_next_pow(width, 2);
+               height_pow2 = Int_next_pow(height, 2);
+
+               LOGW("Loading image of w: %i, h: %i, w2: %d, h2: %d",
+                       width, height, width_pow2, height_pow2);
 
                row_bytes = png_get_rowbytes(png_ptr, info_ptr);
-               pixels = malloc(row_bytes * height);
-               row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * height);
+               row_bytes_pow2 = row_bytes * width_pow2 / width;
+               pixels = malloc(row_bytes_pow2 * height_pow2);
+               row_pointers = (png_bytep*)malloc(sizeof(png_bytep) * height_pow2);
 
                for (i=0; i<height; i++)
                        row_pointers[i] = (png_byte*) malloc(row_bytes);
@@ -188,11 +196,11 @@ redef class Opengles1Image
                png_read_image(png_ptr, row_pointers);
 
                for (i = 0; i < height; i++)
-                       memcpy(pixels + (row_bytes*i),
-                                       row_pointers[i], row_bytes);
+                       memcpy(pixels + (row_bytes_pow2*i), row_pointers[i], row_bytes);
 
-               recv = mnit_opengles_load_image((const uint_least32_t *)pixels, width, height, has_alpha);
                LOGW("OK");
+               recv = mnit_opengles_load_image((const uint_least32_t *)pixels,
+                       width, height, width_pow2, height_pow2, has_alpha);
 
        close_png_ptr:
                if (info_ptr != NULL)
@@ -213,3 +221,13 @@ redef class Opengles1Image
                return recv;
        `}
 end
+
+redef universal Int
+       # The first power of `exp` greater or equal to `self`
+       private fun next_pow(exp: Int): Int
+       do
+               var p = 0
+               while p < self do p = p*exp
+               return p
+       end
+end