Make dump glyph page possible for new texture format

Also implement read-only lock, please use reload() for writing

src/font/font_with_face.cpp

@@ -312,7 +312,20 @@ void FontWithFace::updateCharactersList()
  */
 void FontWithFace::dumpGlyphPage(const std::string& name)
 {
-    // Todo for new texture format
+    for (unsigned int i = 0; i < m_spritebank->getTextureCount(); i++)
+    {
+        video::ITexture* tex = m_spritebank->getTexture(i);
+        core::dimension2d<u32> size = tex->getSize();
+        video::ECOLOR_FORMAT col_format = tex->getColorFormat();
+        void* data = tex->lock();
+        video::IImage* image = irr_driver->getVideoDriver()
+            ->createImageFromData(col_format, size, data,
+            true/*ownForeignMemory*/);
+        tex->unlock();
+        irr_driver->getVideoDriver()->writeImageToFile(image, std::string
+            (name + "_" + StringUtils::toString(i) + ".png").c_str());
+        image->drop();
+    }
 }   // dumpGlyphPage
 
 // ----------------------------------------------------------------------------

src/graphics/stk_texture.cpp

@@ -425,3 +425,22 @@ bool STKTexture::hasMipMaps() const
     return false;
 #endif   // !SERVER_ONLY
 }   // hasMipMaps
+
+//-----------------------------------------------------------------------------
+void* STKTexture::lock(video::E_TEXTURE_LOCK_MODE mode, u32 mipmap_level)
+{
+#ifndef SERVER_ONLY
+    if (m_texture_image)
+        return m_texture_image->lock();
+
+    uint8_t* pixels = new uint8_t[m_size.Width * m_size.Height * 4]();
+    GLint tmp_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &tmp_texture);
+    glBindTexture(GL_TEXTURE_2D, m_texture_name);
+    glGetTexImage(GL_TEXTURE_2D, 0, GL_BGRA, GL_UNSIGNED_BYTE, pixels);
+    glBindTexture(GL_TEXTURE_2D, tmp_texture);
+    return pixels;
+#else
+    return NULL;
+#endif   // !SERVER_ONLY
+}   // lock

src/graphics/stk_texture.hpp

@@ -69,12 +69,7 @@ public:
     virtual ~STKTexture();
     // ------------------------------------------------------------------------
     virtual void* lock(video::E_TEXTURE_LOCK_MODE mode =
-                       video::ETLM_READ_WRITE, u32 mipmap_level = 0)
-    {
-        if (m_texture_image)
-            return m_texture_image->lock();
-        return NULL;
-    }
+                       video::ETLM_READ_WRITE, u32 mipmap_level = 0);
     // ------------------------------------------------------------------------
     virtual void unlock()
     {