Merge topic 'fix_color_cal_in_singlevtpexport'

0b20b2a4 fix a case where color could exceed 1.0
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4737

IO/Export/vtkSingleVTPExporter.cxx

@@ -384,6 +384,39 @@ void vtkSingleVTPExporter::WriteVTP(
     opd->GetPointData()->SetNormals(otnormals);
   }
 
+  // compute the maximum color in case it goes over 1.0
+  float maxColor = 1.0;
+  for (size_t i = 0; i < actors.size(); ++i)
+  {
+    actorData *ad = &(actors[i]);
+    vtkProperty *prop = ad->Actor->GetProperty();
+    double *dcolor = prop->GetDiffuseColor();
+    double diffuse = prop->GetDiffuse();
+    double *acolor = prop->GetAmbientColor();
+    double ambient = prop->GetAmbient();
+    float col[3] = {
+      static_cast<float>(
+        dcolor[0]*diffuse + acolor[0]*ambient),
+      static_cast<float>(
+        dcolor[1]*diffuse + acolor[1]*ambient),
+      static_cast<float>(
+        dcolor[2]*diffuse + acolor[2]*ambient)
+    };
+    if (col[0] > maxColor)
+    {
+      maxColor = col[0];
+    }
+    if (col[1] > maxColor)
+    {
+      maxColor = col[1];
+    }
+    if (col[2] > maxColor)
+    {
+      maxColor = col[2];
+    }
+  }
+  maxColor = 255.0/maxColor;
+
   int pointOffset = 0;
   for (size_t i = 0; i < actors.size(); ++i)
   {
@@ -475,11 +508,11 @@ void vtkSingleVTPExporter::WriteVTP(
     double opacity = prop->GetOpacity();
     float col[4] = {
       static_cast<float>(
-        vtkMath::Min(255.0*(dcolor[0]*diffuse + acolor[0]*ambient),255.0)),
+        vtkMath::Min(maxColor*(dcolor[0]*diffuse + acolor[0]*ambient),255.0)),
       static_cast<float>(
-        vtkMath::Min(255.0*(dcolor[1]*diffuse + acolor[1]*ambient),255.0)),
+        vtkMath::Min(maxColor*(dcolor[1]*diffuse + acolor[1]*ambient),255.0)),
       static_cast<float>(
-        vtkMath::Min(255.0*(dcolor[2]*diffuse + acolor[2]*ambient),255.0)),
+        vtkMath::Min(maxColor*(dcolor[2]*diffuse + acolor[2]*ambient),255.0)),
       static_cast<float>(opacity*255.0)
     };
     if (!is)