Bugfix/maguire7/trilinear shading dev (#4547)

* Fix harshness of lighting power in Headlight

* adding gradient lighting test

* adding baselines

* cleanup

* cleanup: inconsistent spacing and lines > 80 char

* updating release notes

src/avt/Pipeline/Data/avtPhong.C

@@ -36,6 +36,7 @@ avtPhong::avtPhong(double gmax, double lpow)
     : gradMax(gmax), lightingPower(lpow)
 {
     inv_gradMax = 1. / gmax;
+    inv_lightingPower = 1. / lightingPower;
 }
 
 
@@ -246,7 +247,8 @@ double dot(double v1[3], double v2[3]){
 }
 
 
-void avtPhong::AddLightingHeadlight(int index, const avtRay *ray, unsigned char *rgb, double alpha, double matProperties[4]) const
+void avtPhong::AddLightingHeadlight(int index, const avtRay *ray,
+    unsigned char *rgb, double alpha, double matProperties[4]) const
 {
     const LightAttributes &l = lights.GetLight(0);
     if (l.GetEnabledFlag()){
@@ -300,9 +302,18 @@ void avtPhong::AddLightingHeadlight(int index, const avtRay *ray, unsigned char
         if (nl < 0.0)
             nl = -nl;
 
+        //
+        // Lighting power is too harsh if we just multiply it in. Incorporating it
+        // into diffuse gives a much more palatable result.
+        //
         for (int i=0; i<3; i++) 
-              col[i] = ( ((matProperties[0] + (matProperties[1] * nl)) * col[i])   + ((matProperties[2] * pow(nl,matProperties[3])) * alpha) ) * lightingPower;
-            //                amb              +          diff                   +                    spec
+        {
+            // amb + diff + spec
+            double amb  = matProperties[0];
+            double diff = pow(matProperties[1], inv_lightingPower) * nl;
+            double spec = matProperties[2] * pow(nl,matProperties[3]) * alpha;
+            col[i] = ((amb + diff) * col[i]) + spec;
+        }
 
        // convert to unsignedChar
         if ((col[0] * 255) > 255.0)

src/avt/Pipeline/Data/avtPhong.h

@@ -38,6 +38,9 @@
 //    Added ability to reduce amount of lighting for low-gradient-mag areas.
 //    Default values to constructor leave the old behavior (i.e. gradmax=0).
 //
+//    Alister Maguire, Fri Mar 20 16:02:16 PDT 2020
+//    Added inv_lightingPower for use in AddLightingHeadlight.
+//
 // ****************************************************************************
 
 class PIPELINE_API avtPhong : public avtLightingModel
@@ -49,10 +52,13 @@ class PIPELINE_API avtPhong : public avtLightingModel
     virtual void           AddLighting(int, const avtRay *, unsigned char *)
                              const;
 
-    virtual void       AddLightingHeadlight(int, const avtRay *, unsigned char *, double alpha, double matProperties[4]) 
-                 const;
+    virtual void           AddLightingHeadlight(int, const avtRay *,
+                                                unsigned char *,
+                                                double alpha,
+                                                double matProperties[4]) const;
   private:
     double                 gradMax, inv_gradMax, lightingPower;
+    double                 inv_lightingPower;
 };
 
 

src/resources/help/en_US/relnotes3.1.2.html

@@ -31,6 +31,7 @@ enhancements and bug-fixes that were added to this release.</p>
   <li>Fixed ability to save a movie template via the Save Movie Wizard on Windows.</li>
   <li>Fixed bugs with the avtLinesFileFormat reader. The reader can now distinguish 2D from 3D, and it will not remove identical consecutive points that exist on different lines.</li>
   <li>Fixed a crash with the generation of ghost zones using global node ids where there were NULL domains.</li>
+  <li>Fixed a bug that caused trilinear ray casting to have very harsh lighting.</li>
 </ul>
 
 <a name="Enhancements"></a>

src/test/tests/plots/volumePlot.py

@@ -44,6 +44,9 @@
 #    Alister Maguire, Wed Jun  5 11:01:31 PDT 2019
 #    Added opacity attenuation test. 
 #
+#    Alister Maguire, Fri Mar 20 15:36:37 PDT 2020
+#    Added gradient lighting reduction test.
+#
 # ----------------------------------------------------------------------------
 
 def InitAnnotations():
@@ -360,6 +363,42 @@ def TestVolumeSampling():
 
     DeleteAllPlots()
 
+
+def TestGradientLightingReduction():
+
+    view = GetView3D()
+    view.viewNormal = (0.746662961825451, 0.1647201021100829, 0.6444856161303283)
+    SetView3D(view)
+
+    OpenDatabase(silo_data_path("globe.silo"))
+    AddPlot("Volume", "v")
+    DrawPlots()
+
+    #
+    # Trilinear ray casting used to have very harsh results with
+    # gradient lighting reduction. Let's make sure they're better
+    # now.
+    #
+    v = VolumeAttributes()
+    v.lightingFlag = 1
+    v.rendererType = v.RayCasting
+    v.sampling     = v.Trilinear
+
+    v.lowGradientLightingReduction = v.Lower
+    SetPlotOptions(v)
+    Test("graidentLighting_00")
+
+    v.lowGradientLightingReduction = v.Medium
+    SetPlotOptions(v)
+    Test("graidentLighting_01")
+
+    v.lowGradientLightingReduction = v.Higher
+    SetPlotOptions(v)
+    Test("graidentLighting_02")
+
+    DeleteAllPlots()
+    CloseDatabase(silo_data_path("globe.silo"))
+
 #FIXME: For some reason, if you render using the ray caster, 
 #       attempting to render using the default renderer afterwards
 #       will result in a blank test result. I have not been able
@@ -375,5 +414,6 @@ InitAnnotations()
 TestVolumeScaling()
 TestVolumeSampling()
 TestOpacityAttenuation()
+TestGradientLightingReduction()
 
 Exit()

test/baseline/plots/volumePlot/graidentLighting_00.png

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test/baseline/plots/volumePlot/graidentLighting_01.png

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test/baseline/plots/volumePlot/graidentLighting_02.png

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