Brightness slider initialised from all light colours

Initialise the slider to the brightness of the highest RGB component in ALL
selected lights, rather than the first light entity selected. This should
ensure that no individual light is overbrightened when the slider is dragged to
maximum value.

radiant/ui/lightinspector/LightInspector.cpp

@@ -380,6 +380,19 @@ namespace
     }
 }
 
+float LightInspector::highestComponentAllLights() const
+{
+    float highest = 0;
+    for (const Entity* e: _lightEntities)
+    {
+        Vector3 col = entityColour(*e);
+        float entityHighest = highestComponent(col);
+        if (entityHighest > highest)
+            highest = entityHighest;
+    }
+    return highest;
+}
+
 void LightInspector::updateColourPicker()
 {
     // Examine colour of all entities. If they are the same, use this colour in
@@ -404,19 +417,16 @@ void LightInspector::updateColourPicker()
     picker->SetColour(col);
 }
 
-void LightInspector::updateColourWidgets(const Entity& entity)
+void LightInspector::updateColourWidgets()
 {
-    Vector3 colour = entityColour(entity);
-
     // Set colour chooser button
     updateColourPicker();
 
     // Set brightness slider based on the brightest channel. This means that
     // 100% blue and 100% white will both show as maximum brightness, which
     // isn't correct in terms of optics, but prevents the slider from
     // overbrightening a colour and changing the hue.
-    float highest = highestComponent(colour);
-    _brightnessSlider->SetValue(highest * 100.f);
+    _brightnessSlider->SetValue(highestComponentAllLights() * 100.f);
 }
 
 // Get keyvals from entity and insert into text entries
@@ -452,7 +462,7 @@ void LightInspector::getValuesFromEntity()
 		}
 	}
 
-    updateColourWidgets(*entity);
+    updateColourWidgets();
 
     // Set the texture selection from the "texture" key
     _texSelector->setSelection(entity->getKeyValue("texture"));

radiant/ui/lightinspector/LightInspector.h

@@ -77,9 +77,12 @@ class LightInspector :
     void adjustBrightness() const;
 
     void updateColourPicker();
-    void updateColourWidgets(const Entity&);
+    void updateColourWidgets();
     void updateLightShapeWidgets();
 
+    // Get the highest RGB component of ALL selected light colours
+    float highestComponentAllLights() const;
+
     // Update the dialog widgets from keyvals on the first selected entity
     void getValuesFromEntity();