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, 18 insertions, 11 deletions

diff --git a/src/menu/background_color.cpp b/src/menu/background_color.cpp
index f55763b7..031ffe26 100644
--- a/src/menu/background_color.cpp
+++ b/src/menu/background_color.cpp
@@ -28,26 +28,33 @@
 namespace usdx
 {
 	BackgroundColor::BackgroundColor(const DrawableControl &control)
-		: Background(control), color(0,0,0)
+		: Background(control), color(0,0,0), size(0, 0)
 	{
 	}
 
 	BackgroundColor::BackgroundColor(const DrawableControl &control,
 									 const RgbColor &color) :
-		Background(control), color(color)
+		Background(control), color(color), size(0, 0)
 	{
 	}
 
-	void BackgroundColor::draw()
+	void BackgroundColor::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 BackgroundColor::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();
+		}
 
 		glEnableClientState(GL_VERTEX_ARRAY);
 		glEnableClientState(GL_COLOR_ARRAY);