diff --git a/emscripten/crn.cpp b/emscripten/crn.cpp
index 3a37761..cc66b7d 100644
--- a/emscripten/crn.cpp
+++ b/emscripten/crn.cpp
@@ -1,4 +1,26 @@
-#define PLATFORM_NACL
+/* Copyright (c) 2013, Evan Parker, Brandon Jones. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+  * Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
+
+#define PLATFORM_NACL // This disables use of 64 bit integers, among other things.
 
 #include <stddef.h> // For NULL, size_t
 #include <cstring> // for malloc etc
@@ -10,8 +32,9 @@ extern "C" {
   unsigned int crn_get_height(void *src, unsigned int src_size);
   unsigned int crn_get_levels(void *src, unsigned int src_size);
   unsigned int crn_get_dxt_format(void *src, unsigned int src_size);
-  unsigned int crn_get_uncompressed_size(void *p, unsigned int size);
-  void crn_decompress(void *src, unsigned int src_size, void *dst, unsigned int dst_size);
+  unsigned int crn_get_bytes_per_block(void *src, unsigned int src_size);
+  unsigned int crn_get_uncompressed_size(void *p, unsigned int size, unsigned int level);
+  void crn_decompress(void *src, unsigned int src_size, void *dst, unsigned int dst_size, unsigned int firstLevel, unsigned int levelCount);
 }
 
 unsigned int crn_get_width(void *src, unsigned int src_size) {
@@ -38,11 +61,17 @@ unsigned int crn_get_dxt_format(void *src, unsigned int src_size) {
   return tex_info.m_format;
 }
 
-unsigned int crn_get_uncompressed_size(void *src, unsigned int src_size) {
+unsigned int crn_get_bytes_per_block(void *src, unsigned int src_size) {
   crnd::crn_texture_info tex_info;
   crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
-  const crn_uint32 width = tex_info.m_width;
-  const crn_uint32 height = tex_info.m_height;
+  return crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
+}
+
+unsigned int crn_get_uncompressed_size(void *src, unsigned int src_size, unsigned int level) {
+  crnd::crn_texture_info tex_info;
+  crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
+  const crn_uint32 width = tex_info.m_width >> level;
+  const crn_uint32 height = tex_info.m_height >> level;
   const crn_uint32 blocks_x = (width + 3) >> 2;
   const crn_uint32 blocks_y = (height + 3) >> 2;
   const crn_uint32 row_pitch = blocks_x * crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
@@ -50,19 +79,32 @@ unsigned int crn_get_uncompressed_size(void *src, unsigned int src_size) {
   return total_face_size;
 }
 
-void crn_decompress(void *src, unsigned int src_size, void *dst, unsigned int dst_size) {
+void crn_decompress(void *src, unsigned int src_size, void *dst, unsigned int dst_size, unsigned int firstLevel, unsigned int levelCount) {
   crnd::crn_texture_info tex_info;
   crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
-  const crn_uint32 width = tex_info.m_width;
-  const crn_uint32 height = tex_info.m_height;
-  const crn_uint32 blocks_x = (width + 3) >> 2;
-  const crn_uint32 blocks_y = (height + 3) >> 2;
-  const crn_uint32 row_pitch = blocks_x * crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
+
+  crn_uint32 width = tex_info.m_width >> firstLevel;
+  crn_uint32 height = tex_info.m_height >> firstLevel;
+  crn_uint32 bytes_per_block = crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
+
+  void *pDecomp_images[1];
+  pDecomp_images[0] = dst;
 
   crnd::crnd_unpack_context pContext =
       crnd::crnd_unpack_begin(static_cast<crn_uint8*>(src), src_size);
-  void *pDecomp_images[1];
-  pDecomp_images[0] = dst;
-  crnd::crnd_unpack_level(pContext, pDecomp_images, dst_size, row_pitch, 0);
+
+  for (int i = firstLevel; i < firstLevel + levelCount; ++i) {
+    crn_uint32 blocks_x = (width + 3) >> 2;
+    crn_uint32 blocks_y = (height + 3) >> 2;
+    crn_uint32 row_pitch = blocks_x * bytes_per_block;
+    crn_uint32 total_level_size = row_pitch * blocks_y;
+
+    crnd::crnd_unpack_level(pContext, pDecomp_images, total_level_size, row_pitch, i);
+    pDecomp_images[0] = (char*)pDecomp_images[0] + total_level_size;
+
+    width = width >> 1;
+    height = height >> 1;
+  }
+
   crnd::crnd_unpack_end(pContext);
 }
\ No newline at end of file