+ /**
+ * set the alpha component of the cloud base color. Normally this
+ * should be 1.0, but you can set it anywhere in the range of 0.0
+ * to 1.0 to fade a cloud layer in or out.
+ * @param alpha cloud alpha value (0.0 to 1.0)
+ */
+ inline void setAlpha( float alpha ) {
+ if ( alpha < 0.0 ) { alpha = 0.0; }
+ if ( alpha > 1.0 ) { alpha = 1.0; }
+ cloud_alpha = alpha;
+ }
+