add load_texture_rw interface for load texture from buffer

src/sdl2/image/mod.rs

@@ -135,6 +135,7 @@ impl<'a> SaveSurface for Surface<'a> {
 /// Method extensions for creating Textures from a `TextureCreator`
 pub trait LoadTexture {
     fn load_texture<P: AsRef<Path>>(&self, filename: P) -> Result<Texture, String>;
+    fn load_texture_rw(&self, buf: &[u8]) -> Result<Texture, String>;
 }
 
 impl<T> LoadTexture for TextureCreator<T> {
@@ -150,6 +151,18 @@ impl<T> LoadTexture for TextureCreator<T> {
             }
         }
     }
+
+    fn load_texture_rw(&self, buf: &[u8]) -> Result<Texture, String> {
+        unsafe {
+            let buf = sdl2_sys::SDL_RWFromMem(buf.as_ptr() as *mut libc::c_void, buf.len() as i32);
+            let raw = image::IMG_LoadTexture_RW(self.raw(), buf, 1); // close(free) buff after load
+            if (raw as *mut ()).is_null() {
+                Err(get_error())
+            } else {
+                Ok(self.raw_create_texture(raw))
+            }
+        }
+    }
 }
 
 /// Context manager for `sdl2_image` to manage quitting. Can't do much with it but