added GetOverlayAlpha()

c/segNet.cpp

@@ -283,6 +283,9 @@ segNet* segNet::Create( const char* prototxt, const char* model, const char* lab
 	net->loadClassLabels(labels_path);
 	net->loadClassColors(colors_path);
 
+	// set overlay alpha value
+	net->SetOverlayAlpha(SEGNET_DEFAULT_ALPHA);
+
 	return net;
 }
 
@@ -440,6 +443,21 @@ void segNet::SetClassColor( uint32_t classIndex, float r, float g, float b, floa
 }
 
 
+// GetOverlayAlpha
+float segNet::GetOverlayAlpha() const
+{
+	const uint32_t numClasses = GetNumClasses();
+
+	for( uint32_t n=0; n < numClasses; n++ )
+	{
+		if( !mColorsAlphaSet[n] )
+			return mClassColors[n].w;
+	}
+
+	return SEGNET_DEFAULT_ALPHA;
+}
+
+
 // SetOverlayAlpha
 void segNet::SetOverlayAlpha( float alpha, bool explicit_exempt )
 {

c/segNet.h

@@ -287,6 +287,11 @@ class segNet : public tensorNet
 	 */
 	void SetClassColor( uint32_t classIndex, float r, float g, float b, float a=255.0f );
 
+	/**
+	 * Retrieve the overlay alpha blending value for classes that don't have it explicitly set.
+	 */
+	float GetOverlayAlpha() const;
+
 	/**
  	 * Set overlay alpha blending value for all classes (between 0-255),
 	 * (optionally except for those that have been explicitly set).