validated bling phong

src/main/java/bdv/jogl/VolumeRenderer/ShaderPrograms/ShaderSources/functions/volumeninterpreter/IsoSurfaceVolumeInterpreter.java

@@ -76,9 +76,11 @@ public class IsoSurfaceVolumeInterpreter extends AbstractVolumeInterpreter {
 				"						vec3 lightDirs,",
 				"						vec3 iIn){",
 				"	vec3 halfVec = (lightDirs+lookVector)/length(lightDirs+lookVector);",
+				"	float ln = dot(lightDirs, normal);",
+				"	float v =max (sign(ln),0.0);",
 				"	vec3 iOut = constants.x * iAmbient;//ambient",
-				"	iOut += iIn*(constants.y*abs(dot(lightDirs, normal)));//diffuse",
-				"	iOut += iIn*(constants.z*pow( abs(dot(halfVec,normal)),10.0));//specular",
+				"	iOut += iIn*(constants.y*max(ln,0.0));//diffuse",
+				"	iOut += v*iIn*(constants.z*max(pow( dot(halfVec,normal),10.0),0.0));//specular",
 				"	",
 				"	return iOut;",
 				"}",
@@ -106,7 +108,7 @@ public class IsoSurfaceVolumeInterpreter extends AbstractVolumeInterpreter {
 				"		vec4 gradient = "+gradEval.call(new String[]{"refinedVal.xyz"})+";",
 				"		color.rgb = blinnPhongShading(	inconstants,",
 				"										ambientColor/*c.rgb*/,",
-				"										normalize(gradient.xyz),",
+				"										-normalize(gradient.xyz),",
 				"										-1.0 * "+sgvRayDirections+",",
 				"										normalize( "+suvEyePosition+" - "+sgvRayPositions+"),",
 				"										"+suvLightIntensiy+");",