menu/background_*: vertices are only recalculated if the size changed

The size of the parent component is cached by the backgrounds and the
vertices to draw the backgrounds are only calculated again, if the
size of the parent component changed.

1 files changed, 15 insertions, 9 deletions

diff --git a/src/menu/background_image.cpp b/src/menu/background_image.cpp
index bb398304..451587f7 100644
--- a/src/menu/background_image.cpp
+++ b/src/menu/background_image.cpp
@@ -30,7 +30,7 @@ namespace usdx
 {
 	BackgroundImage::BackgroundImage(const DrawableControl &control,
 									 boost::filesystem::wpath filename) :
-		Background(control)
+		Background(control), texture(NULL), size(0,0)
 	{
 		texture = new Disposer<Texture>(new Texture(filename));
 	}
@@ -42,18 +42,24 @@ namespace usdx
 			texture = NULL;
 		}
 	}
+
+	void BackgroundImage::updateVertices() {
+		vertices[0] = 0;
+		vertices[1] = get_parent().get_height();
+		vertices[2] = get_parent().get_width();
+		vertices[3] = get_parent().get_height();
+		vertices[4] = get_parent().get_width();
+		vertices[5] = 0;
+		vertices[6] = 0;
+		vertices[7] = 0;
 	}
 
 	void BackgroundImage::draw(void)
 	{
-		this->vertices[0] = 0;
-		this->vertices[1] = get_parent().get_height();
-		this->vertices[2] = get_parent().get_width();
-		this->vertices[3] = get_parent().get_height();
-		this->vertices[4] = get_parent().get_width();
-		this->vertices[5] = 0;
-		this->vertices[6] = 0;
-		this->vertices[7] = 0;
+		if (size != get_parent().get_size()) {
+			this->updateVertices();
+			size = get_parent().get_size();
+		}
 
 		Activator<Texture> t(texture->get());