diff --git a/layers/texture_layer_merger.cpp b/layers/texture_layer_merger.cpp
index 00d40e2..39e2d44 100644
--- a/layers/texture_layer_merger.cpp
+++ b/layers/texture_layer_merger.cpp
@@ -48,7 +48,7 @@ void TextureLayerMerger::set_texture_flags(uint32_t p_flags) {
 Color TextureLayerMerger::get_base_color() const {
 	return _base_color;
 }
-void TextureLayerMerger::set_base_color(const Color p_color) {
+void TextureLayerMerger::set_base_color(const Color &p_color) {
 	_base_color = p_color;
 }
 
@@ -72,7 +72,7 @@ Ref<ImageTexture> TextureLayerMerger::get_result_as_texture() const {
 	return tex;
 }
 
-void TextureLayerMerger::add_texture(Ref<Texture> p_texture, Color p_color, Vector2 p_position, Rect2 p_rect) {
+void TextureLayerMerger::add_texture(const Ref<Texture> &p_texture, const Color &p_color, const Vector2 &p_position, Rect2 p_rect) {
 	ERR_FAIL_COND(!p_texture.is_valid());
 
 	LayerMergerEntry entry;
@@ -118,7 +118,7 @@ Ref<Texture> TextureLayerMerger::get_texture(const int p_index) {
 
 	return _entries.get(p_index).texture;
 }
-void TextureLayerMerger::set_texture(const int p_index, Ref<Texture> p_texture) {
+void TextureLayerMerger::set_texture(const int p_index, const Ref<Texture> &p_texture) {
 	ERR_FAIL_INDEX(p_index, _entries.size());
 
 	_entries.get(p_index).texture = p_texture;
@@ -129,7 +129,7 @@ Color TextureLayerMerger::get_color(const int p_index) {
 
 	return _entries.get(p_index).color;
 }
-void TextureLayerMerger::set_color(const int p_index, Color p_color) {
+void TextureLayerMerger::set_color(const int p_index, const Color &p_color) {
 	ERR_FAIL_INDEX(p_index, _entries.size());
 
 	_entries.get(p_index).color = p_color;
@@ -140,7 +140,7 @@ Vector2 TextureLayerMerger::get_position(const int p_index) {
 
 	return _entries.get(p_index).position;
 }
-void TextureLayerMerger::set_position(const int p_index, Vector2 p_position) {
+void TextureLayerMerger::set_position(const int p_index, const Vector2 &p_position) {
 	ERR_FAIL_INDEX(p_index, _entries.size());
 
 	_entries.get(p_index).position = p_position;
@@ -151,7 +151,7 @@ Rect2 TextureLayerMerger::get_rect(const int p_index) {
 
 	return _entries.get(p_index).rect;
 }
-void TextureLayerMerger::set_rect(const int p_index, Rect2 p_rect) {
+void TextureLayerMerger::set_rect(const int p_index, const Rect2 &p_rect) {
 	ERR_FAIL_INDEX(p_index, _entries.size());
 
 	_entries.get(p_index).rect = p_rect;
diff --git a/layers/texture_layer_merger.h b/layers/texture_layer_merger.h
index 7df69d6..b1b5617 100644
--- a/layers/texture_layer_merger.h
+++ b/layers/texture_layer_merger.h
@@ -57,29 +57,29 @@ public:
 	void set_height(const int p_value);
 
 	uint32_t get_texture_flags() const;
-	void set_texture_flags(uint32_t p_flags);
+	void set_texture_flags(const uint32_t p_flags);
 
 	Color get_base_color() const;
-	void set_base_color(const Color p_color);
+	void set_base_color(const Color &p_color);
 
 	Ref<Image> get_data() const;
 	void set_data(const Ref<Image> &p_image);
 
 	Ref<ImageTexture> get_result_as_texture() const;
 
-	void add_texture(Ref<Texture> p_texture, Color p_color = Color(1, 1, 1, 1), Vector2 p_position = Vector2(), Rect2 p_rect = Rect2());
+	void add_texture(const Ref<Texture> &p_texture, const Color &p_color = Color(1, 1, 1, 1), const Vector2 &p_position = Vector2(), Rect2 p_rect = Rect2());
 
 	Ref<Texture> get_texture(const int p_index);
-	void set_texture(const int p_index, Ref<Texture> p_texture);
+	void set_texture(const int p_index, const Ref<Texture> &p_texture);
 
 	Color get_color(const int p_index);
-	void set_color(const int p_index, Color p_color);
+	void set_color(const int p_index, const Color &p_color);
 
 	Vector2 get_position(const int p_index);
-	void set_position(const int p_index, Vector2 p_position);
+	void set_position(const int p_index, const Vector2 &p_position);
 
 	Rect2 get_rect(const int p_index);
-	void set_rect(const int p_index, Rect2 p_rect);
+	void set_rect(const int p_index, const Rect2 &p_rect);
 
 	void remove_texture(const int p_index);
 	int get_texture_count();
diff --git a/texture_merger.cpp b/texture_merger.cpp
index c622be6..dd4f741 100644
--- a/texture_merger.cpp
+++ b/texture_merger.cpp
@@ -59,7 +59,7 @@ void TextureMerger::set_keep_original_atlases(const bool value) {
 Color TextureMerger::get_background_color() const {
 	return _packer->get_background_color();
 }
-void TextureMerger::set_background_color(const Color color) {
+void TextureMerger::set_background_color(const Color &color) {
 	_packer->set_background_color(color);
 }
 
@@ -80,7 +80,7 @@ void TextureMerger::set_automatic_merge(const bool value) {
 Ref<TexturePacker> TextureMerger::get_packer() const {
 	return _packer;
 }
-void TextureMerger::set_packer(const Ref<TexturePacker> packer) {
+void TextureMerger::set_packer(const Ref<TexturePacker> &packer) {
 	_packer = packer;
 }
 
@@ -130,7 +130,7 @@ void TextureMerger::set_textures(const Vector<Variant> &textures) {
 		set_dirty(true);
 }
 
-Ref<AtlasTexture> TextureMerger::add_texture(Ref<Texture> texture) {
+Ref<AtlasTexture> TextureMerger::add_texture(const Ref<Texture> &texture) {
 	ERR_FAIL_COND_V(!texture.is_valid(), Ref<AtlasTexture>());
 
 	_textures.push_back(texture);
@@ -151,23 +151,23 @@ Ref<AtlasTexture> TextureMerger::add_texture(Ref<Texture> texture) {
 	return tex;
 }
 
-Ref<Texture> TextureMerger::get_original_texture(int index) {
+Ref<Texture> TextureMerger::get_original_texture(const int index) {
 	return _packer->get_original_texture(index);
 }
 
-bool TextureMerger::contains_texture(Ref<Texture> texture) {
+bool TextureMerger::contains_texture(const Ref<Texture> &texture) {
 	return _packer->contains_texture(texture);
 }
 
-Ref<AtlasTexture> TextureMerger::get_texture(Ref<Texture> texture) {
+Ref<AtlasTexture> TextureMerger::get_texture(const Ref<Texture> &texture) {
 	return _packer->get_texture(texture);
 }
 
-Ref<AtlasTexture> TextureMerger::get_texture_index(int index) {
+Ref<AtlasTexture> TextureMerger::get_texture_index(const int index) {
 	return _packer->get_texture_index(index);
 }
 
-bool TextureMerger::unref_texture_index(int index) {
+bool TextureMerger::unref_texture_index(const int index) {
 	if (_packer->unref_texture_index(index)) {
 		if (has_method("_texture_removed"))
 			call("_texture_removed");
@@ -182,7 +182,7 @@ bool TextureMerger::unref_texture_index(int index) {
 	return false;
 }
 
-bool TextureMerger::unref_texture(Ref<Texture> texture) {
+bool TextureMerger::unref_texture(const Ref<Texture> &texture) {
 	if (_packer->unref_texture(texture)) {
 		if (has_method("_texture_removed"))
 			call("_texture_removed");
@@ -197,7 +197,7 @@ bool TextureMerger::unref_texture(Ref<Texture> texture) {
 	return false;
 }
 
-void TextureMerger::remove_texture_index(int index) {
+void TextureMerger::remove_texture_index(const int index) {
 	_packer->remove_texture_index(index);
 
 	if (has_method("_texture_removed"))
@@ -208,7 +208,7 @@ void TextureMerger::remove_texture_index(int index) {
 	set_dirty(true);
 }
 
-void TextureMerger::remove_texture(Ref<Texture> texture) {
+void TextureMerger::remove_texture(const Ref<Texture> &texture) {
 	_packer->remove_texture(texture);
 
 	if (has_method("_texture_removed"))
@@ -227,7 +227,7 @@ void TextureMerger::clear() {
 	_packer->clear();
 }
 
-Ref<ImageTexture> TextureMerger::get_generated_texture(int index) {
+Ref<ImageTexture> TextureMerger::get_generated_texture(const int index) {
 	return _packer->get_generated_texture(index);
 }
 int TextureMerger::get_generated_texture_count() {
diff --git a/texture_merger.h b/texture_merger.h
index e54652d..d0e40e7 100644
--- a/texture_merger.h
+++ b/texture_merger.h
@@ -54,7 +54,7 @@ public:
 	void set_keep_original_atlases(const bool value);
 
 	Color get_background_color() const;
-	void set_background_color(const Color color);
+	void set_background_color(const Color &color);
 
 	int get_margin() const;
 	void set_margin(const int margin);
@@ -63,26 +63,26 @@ public:
 	void set_automatic_merge(const bool value);
 
 	Ref<TexturePacker> get_packer() const;
-	void set_packer(const Ref<TexturePacker> packer);
+	void set_packer(const Ref<TexturePacker> &packer);
 
 	Vector<Variant> get_textures();
 	void set_textures(const Vector<Variant> &textures);
 
-	Ref<AtlasTexture> add_texture(Ref<Texture> texture);
-	Ref<AtlasTexture> get_texture(Ref<Texture> texture);
-	Ref<AtlasTexture> get_texture_index(int index);
-	Ref<Texture> get_original_texture(int index);
-	bool contains_texture(Ref<Texture> texture);
+	Ref<AtlasTexture> add_texture(const Ref<Texture> &texture);
+	Ref<AtlasTexture> get_texture(const Ref<Texture> &texture);
+	Ref<AtlasTexture> get_texture_index(const int index);
+	Ref<Texture> get_original_texture(const int index);
+	bool contains_texture(const Ref<Texture> &texture);
 
-	bool unref_texture_index(int index);
-	bool unref_texture(Ref<Texture> texture);
-	void remove_texture_index(int index);
-	void remove_texture(Ref<Texture> texture);
+	bool unref_texture_index(const int index);
+	bool unref_texture(const Ref<Texture> &texture);
+	void remove_texture_index(const int index);
+	void remove_texture(const Ref<Texture> &texture);
 
 	int get_texture_count();
 	void clear();
 
-	Ref<ImageTexture> get_generated_texture(int index);
+	Ref<ImageTexture> get_generated_texture(const int index);
 	int get_generated_texture_count();
 
 	void merge();
diff --git a/texture_packer.cpp b/texture_packer.cpp
index ec6133a..b2b82f7 100644
--- a/texture_packer.cpp
+++ b/texture_packer.cpp
@@ -46,7 +46,7 @@ void TexturePacker::set_keep_original_atlases(const bool value) {
 Color TexturePacker::get_background_color() const {
 	return _background_color;
 }
-void TexturePacker::set_background_color(const Color color) {
+void TexturePacker::set_background_color(const Color &color) {
 	_background_color = color;
 }
 
@@ -57,7 +57,7 @@ void TexturePacker::set_margin(const int margin) {
 	_margin = margin;
 }
 
-Ref<AtlasTexture> TexturePacker::add_texture(Ref<Texture> texture) {
+Ref<AtlasTexture> TexturePacker::add_texture(const Ref<Texture> &texture) {
 	ERR_FAIL_COND_V(!texture.is_valid(), Ref<AtlasTexture>());
 
 	Ref<AtlasTexture> atlas_text = texture;
@@ -140,7 +140,7 @@ Ref<AtlasTexture> TexturePacker::add_texture(Ref<Texture> texture) {
 	return tex;
 }
 
-Ref<AtlasTexture> TexturePacker::get_texture(Ref<Texture> texture) {
+Ref<AtlasTexture> TexturePacker::get_texture(const Ref<Texture> &texture) {
 	for (int i = 0; i < _rects.size(); ++i) {
 		rect_xywhf *r = _rects.get(i);
 
@@ -160,19 +160,19 @@ Ref<AtlasTexture> TexturePacker::get_texture(Ref<Texture> texture) {
 	return Ref<Texture>();
 }
 
-Ref<AtlasTexture> TexturePacker::get_texture_index(int index) {
+Ref<AtlasTexture> TexturePacker::get_texture_index(const int index) {
 	ERR_FAIL_INDEX_V(index, _rects.size(), Ref<AtlasTexture>());
 
 	return _rects.get(index)->atlas_texture;
 }
 
-Ref<Texture> TexturePacker::get_original_texture(int index) {
+Ref<Texture> TexturePacker::get_original_texture(const int index) {
 	ERR_FAIL_INDEX_V(index, _rects.size(), Ref<Texture>());
 
 	return _rects.get(index)->original_texture;
 }
 
-bool TexturePacker::contains_texture(Ref<Texture> texture) {
+bool TexturePacker::contains_texture(const Ref<Texture> &texture) {
 	for (int i = 0; i < _rects.size(); ++i) {
 		rect_xywhf *r = _rects.get(i);
 
@@ -192,7 +192,7 @@ bool TexturePacker::contains_texture(Ref<Texture> texture) {
 	return false;
 }
 
-bool TexturePacker::unref_texture_index(int index) {
+bool TexturePacker::unref_texture_index(const int index) {
 	ERR_FAIL_INDEX_V(index, _rects.size(), false);
 
 	rect_xywhf *r = _rects.get(index);
@@ -213,7 +213,7 @@ bool TexturePacker::unref_texture_index(int index) {
 	return false;
 }
 
-bool TexturePacker::unref_texture(Ref<Texture> texture) {
+bool TexturePacker::unref_texture(const Ref<Texture> &texture) {
 	for (int i = 0; i < _rects.size(); ++i) {
 		rect_xywhf *r = _rects.get(i);
 
@@ -247,7 +247,7 @@ bool TexturePacker::unref_texture(Ref<Texture> texture) {
 	return false;
 }
 
-void TexturePacker::remove_texture_index(int index) {
+void TexturePacker::remove_texture_index(const int index) {
 	ERR_FAIL_INDEX(index, _rects.size());
 
 	rect_xywhf *r = _rects.get(index);
@@ -258,7 +258,7 @@ void TexturePacker::remove_texture_index(int index) {
 	memdelete(r);
 }
 
-void TexturePacker::remove_texture(Ref<Texture> texture) {
+void TexturePacker::remove_texture(const Ref<Texture> &texture) {
 	for (int i = 0; i < _rects.size(); ++i) {
 		rect_xywhf *r = _rects.get(i);
 
@@ -307,7 +307,7 @@ void TexturePacker::clear() {
 	_generated_textures.clear();
 }
 
-Ref<ImageTexture> TexturePacker::get_generated_texture(int index) {
+Ref<ImageTexture> TexturePacker::get_generated_texture(const int index) {
 	ERR_FAIL_INDEX_V(index, _generated_textures.size(), Ref<ImageTexture>());
 
 	return _generated_textures.get(index);
@@ -418,7 +418,7 @@ void TexturePacker::merge() {
 	}
 }
 
-int TexturePacker::get_offset_for_format(Image::Format format) {
+int TexturePacker::get_offset_for_format(const Image::Format format) {
 	switch (format) {
 		case Image::FORMAT_RGB8:
 			return 3;
diff --git a/texture_packer.h b/texture_packer.h
index c616348..3c5900c 100644
--- a/texture_packer.h
+++ b/texture_packer.h
@@ -66,34 +66,34 @@ public:
 	void set_keep_original_atlases(const bool value);
 
 	Color get_background_color() const;
-	void set_background_color(const Color color);
+	void set_background_color(const Color &color);
 
 	int get_margin() const;
 	void set_margin(const int margin);
 
-	Ref<AtlasTexture> add_texture(Ref<Texture> texture);
+	Ref<AtlasTexture> add_texture(const Ref<Texture> &texture);
 
-	Ref<AtlasTexture> get_texture(Ref<Texture> texture);
-	Ref<AtlasTexture> get_texture_index(int index);
+	Ref<AtlasTexture> get_texture(const Ref<Texture> &texture);
+	Ref<AtlasTexture> get_texture_index(const int index);
 
-	Ref<Texture> get_original_texture(int index);
+	Ref<Texture> get_original_texture(const int index);
 
-	bool contains_texture(Ref<Texture> texture);
+	bool contains_texture(const Ref<Texture> &texture);
 
-	bool unref_texture_index(int index);
-	bool unref_texture(Ref<Texture> texture);
-	void remove_texture_index(int index);
-	void remove_texture(Ref<Texture> texture);
+	bool unref_texture_index(const int index);
+	bool unref_texture(const Ref<Texture> &texture);
+	void remove_texture_index(const int index);
+	void remove_texture(const Ref<Texture> &texture);
 
 	int get_texture_count();
 	void clear();
 
-	Ref<ImageTexture> get_generated_texture(int index);
+	Ref<ImageTexture> get_generated_texture(const int index);
 	int get_generated_texture_count();
 
 	void merge();
 
-	int get_offset_for_format(Image::Format format);
+	int get_offset_for_format(const Image::Format format);
 
 	TexturePacker();
 	~TexturePacker();