From 76228f2d0c789f740251c98d946c22e24cc3c8b4 Mon Sep 17 00:00:00 2001
From: Azaezel <quillus@hotmail.com>
Date: Wed, 9 Mar 2016 20:02:39 -0600
Subject: [PATCH] alpha masking for buttons. original attribution @dottools

---
 .../gui/buttons/guiBitmapButtonCtrl.cpp       | 41 +++++++++++++++++++
 .../source/gui/buttons/guiBitmapButtonCtrl.h  |  4 ++
 2 files changed, 45 insertions(+)

diff --git a/Engine/source/gui/buttons/guiBitmapButtonCtrl.cpp b/Engine/source/gui/buttons/guiBitmapButtonCtrl.cpp
index ce95475f2..29d81231f 100644
--- a/Engine/source/gui/buttons/guiBitmapButtonCtrl.cpp
+++ b/Engine/source/gui/buttons/guiBitmapButtonCtrl.cpp
@@ -124,6 +124,7 @@ GuiBitmapButtonCtrl::GuiBitmapButtonCtrl()
    mUseModifiers = false;
    mUseStates = true;
    setExtent( 140, 30 );
+   mMasked = false;
 }
 
 //-----------------------------------------------------------------------------
@@ -157,6 +158,7 @@ void GuiBitmapButtonCtrl::initPersistFields()
          "Defaults to true.\n\n"
          "If you do not use per-state images on this button set this to false to speed up the loading process "
          "by inhibiting searches for the individual images." );
+      addField("masked", TypeBool, Offset(mMasked, GuiBitmapButtonCtrl),"Use alpha masking for interaction.");
          
    endGroup( "Bitmap" );
       
@@ -551,3 +553,42 @@ void GuiBitmapButtonTextCtrl::renderButton( GFXTexHandle &texture, const Point2I
    GFX->getDrawUtil()->setBitmapModulation( mProfile->mFontColor );
    renderJustifiedText(textPos, getExtent(), mButtonText);
 }
+
+bool GuiBitmapButtonCtrl::pointInControl(const Point2I& parentCoordPoint)
+{
+   if (mMasked && getTextureForCurrentState())
+   {
+      ColorI rColor(0, 0, 0, 0);
+      GBitmap* bmp;
+
+      const RectI &bounds = getBounds();
+      S32 xt = parentCoordPoint.x - bounds.point.x;
+      S32 yt = parentCoordPoint.y - bounds.point.y;
+
+      bmp = getTextureForCurrentState().getBitmap();
+      if (!bmp)
+      {
+         setBitmap(mBitmapName);
+         bmp = getTextureForCurrentState().getBitmap();
+      }
+
+      S32 relativeXRange = this->getExtent().x;
+      S32 relativeYRange = this->getExtent().y;
+      S32 fileXRange = bmp->getHeight(0);
+      S32 fileYRange = bmp->getWidth(0);
+      //Con::errorf("xRange:[%i -- %i],  Range:[%i -- %i]  pos:(%i,%i)",relativeXRange,fileXRange,relativeYRange,fileYRange,xt,yt);
+
+      S32 fileX = (xt*fileXRange) / relativeXRange;
+      S32 fileY = (yt*fileYRange) / relativeYRange;
+      //Con::errorf("Checking %s @ (%i,%i)",this->getName(),fileX,fileY);
+
+      bmp->getColor(fileX, fileY, rColor);
+
+      if (rColor.alpha)
+         return true;
+      else
+         return false;
+   }
+   else
+      return Parent::pointInControl(parentCoordPoint);
+}
\ No newline at end of file
diff --git a/Engine/source/gui/buttons/guiBitmapButtonCtrl.h b/Engine/source/gui/buttons/guiBitmapButtonCtrl.h
index c42b4f3f4..2a9d464e7 100644
--- a/Engine/source/gui/buttons/guiBitmapButtonCtrl.h
+++ b/Engine/source/gui/buttons/guiBitmapButtonCtrl.h
@@ -113,6 +113,9 @@ class GuiBitmapButtonCtrl : public GuiButtonCtrl
       /// File name for bitmap.
       String mBitmapName;
       
+      /// alpha masking
+      bool mMasked;
+      
       ///
       Textures mTextures[ NumModifiers ];
       
@@ -163,6 +166,7 @@ class GuiBitmapButtonCtrl : public GuiButtonCtrl
       virtual void onRender(Point2I offset, const RectI &updateRect);
 
       static void initPersistFields();
+      bool pointInControl(const Point2I& parentCoordPoint);
 
       DECLARE_CONOBJECT(GuiBitmapButtonCtrl);
       DECLARE_DESCRIPTION( "A button control rendered entirely from bitmaps.\n"