diff --git a/examples/NeoPixelDibTest/NeoPixelDibTest.ino b/examples/NeoPixelDibTest/NeoPixelDibTest.ino
index 83fbfdc..1a13c13 100644
--- a/examples/NeoPixelDibTest/NeoPixelDibTest.ino
+++ b/examples/NeoPixelDibTest/NeoPixelDibTest.ino
@@ -34,10 +34,12 @@ const RgbColor White(255);
 const RgbColor Black(0);
 
 // define a custom shader object that provides brightness support
-class BrightnessShader
+// based upon the NeoShaderBase
+class BrightnessShader : public NeoShaderBase
 {
 public:
   BrightnessShader():
+    NeoShaderBase(),
     _brightness(255) // default to full bright
   {}
 
@@ -57,6 +59,7 @@ public:
   void setBrightness(uint8_t brightness)
   {
     _brightness = brightness;
+    Dirty(); // must call dirty when a property changes
   }
 
   // provide an accessor to get brightness
@@ -141,12 +144,15 @@ void loop()
   
   Serial.println(brightness);
    
-  // render the image using the shader
+  
+  // render the image using the shader and then call Show()
+  // these two should be called together in order
+  //
+
   // need to provide the type of color feature for the strip and
   // the type of our custom shader
   image.Render<NeoGrbFeature, BrightnessShader>(strip, shader);
-
-  // and just show the strip
   strip.Show();
+
 }
 
diff --git a/src/NeoPixelBus.h b/src/NeoPixelBus.h
index c886b73..4d43a11 100644
--- a/src/NeoPixelBus.h
+++ b/src/NeoPixelBus.h
@@ -27,6 +27,9 @@ License along with NeoPixel.  If not, see
 
 #include <Arduino.h>
 
+// '_state' flags for internal state
+#define NEO_DIRTY   0x80 // a change was made to pixel data that requires a show
+
 #include "internal/NeoHueBlend.h"
 
 #include "internal/RgbColor.h"
@@ -78,8 +81,6 @@ License along with NeoPixel.  If not, see
 #include "internal/DotStarSpiMethod.h"
 #endif
 
-// '_state' flags for internal state
-#define NEO_DIRTY   0x80 // a change was made to pixel data that requires a show
 
 template<typename T_COLOR_FEATURE, typename T_METHOD> class NeoPixelBus
 {
@@ -89,18 +90,21 @@ public:
    
     NeoPixelBus(uint16_t countPixels, uint8_t pin) :
         _countPixels(countPixels),
+        _state(0),
         _method(pin, countPixels, T_COLOR_FEATURE::PixelSize)
     {
     }
 
     NeoPixelBus(uint16_t countPixels, uint8_t pinClock, uint8_t pinData) :
         _countPixels(countPixels),
+        _state(0),
         _method(pinClock, pinData, countPixels, T_COLOR_FEATURE::PixelSize)
     {
     }
 
     NeoPixelBus(uint16_t countPixels) :
         _countPixels(countPixels),
+        _state(0),
         _method(countPixels, T_COLOR_FEATURE::PixelSize)
     {
     }
diff --git a/src/internal/NeoDib.h b/src/internal/NeoDib.h
index ddbd140..ef69ce6 100644
--- a/src/internal/NeoDib.h
+++ b/src/internal/NeoDib.h
@@ -25,13 +25,42 @@ License along with NeoPixel.  If not, see
 -------------------------------------------------------------------------*/
 #pragma once
 
+class NeoShaderBase
+{
+public:
+    NeoShaderBase() :
+        _state(0)
+    {
+    }
+
+    bool IsDirty() const
+    {
+        return  (_state & NEO_DIRTY);
+    };
+
+    void Dirty()
+    {
+        _state |= NEO_DIRTY;
+    };
+
+    void ResetDirty()
+    {
+        _state &= ~NEO_DIRTY;
+    };
+
+protected:
+    uint8_t _state;     // internal state
+};
+
 template<typename T_COLOR_OBJECT> class NeoDib
 {
 public:
     NeoDib(uint16_t countPixels) :
-        _countPixels(countPixels)
+        _countPixels(countPixels),
+        _state(0)
     {
         _pixels = (T_COLOR_OBJECT*)malloc(PixelsSize());
+        ResetDirty();
     }
 
     ~NeoDib()
@@ -66,6 +95,7 @@ public:
         if (indexPixel < PixelCount())
         {
             _pixels[indexPixel] = color;
+            Dirty();
         }
     };
 
@@ -85,24 +115,47 @@ public:
         {
             _pixels[pixel] = color;
         }
+        Dirty();
     };
 
-    template <typename T_COLOR_FEATURE, typename T_SHADER> void Render(NeoBufferContext<T_COLOR_FEATURE> destBuffer, T_SHADER shader)
+    template <typename T_COLOR_FEATURE, typename T_SHADER> void Render(NeoBufferContext<T_COLOR_FEATURE> destBuffer, T_SHADER& shader)
     {
-        uint16_t countPixels = destBuffer.PixelCount();
-        if (countPixels > _countPixels)
+        if (IsDirty() || shader.IsDirty())
         {
-            countPixels = _countPixels;
-        }
+            uint16_t countPixels = destBuffer.PixelCount();
+            if (countPixels > _countPixels)
+            {
+                countPixels = _countPixels;
+            }
 
-        for (uint16_t indexPixel = 0; indexPixel < countPixels; indexPixel++)
-        {
-            T_COLOR_OBJECT color = shader.Apply(indexPixel, _pixels[indexPixel]);
-            T_COLOR_FEATURE::applyPixelColor(destBuffer.Pixels, indexPixel, color);
+            for (uint16_t indexPixel = 0; indexPixel < countPixels; indexPixel++)
+            {
+                T_COLOR_OBJECT color = shader.Apply(indexPixel, _pixels[indexPixel]);
+                T_COLOR_FEATURE::applyPixelColor(destBuffer.Pixels, indexPixel, color);
+            }
+
+            shader.ResetDirty();
+            ResetDirty();
         }
     }
 
+    bool IsDirty() const
+    {
+        return  (_state & NEO_DIRTY);
+    };
+
+    void Dirty()
+    {
+        _state |= NEO_DIRTY;
+    };
+
+    void ResetDirty()
+    {
+        _state &= ~NEO_DIRTY;
+    };
+
 private:
     const uint16_t _countPixels; // Number of RGB LEDs in strip
     T_COLOR_OBJECT* _pixels;
+    uint8_t _state;     // internal state
 };
\ No newline at end of file