Engine directory for ticket #1

Engine/source/T3D/decal/decalInstance.cpp

@@ -0,0 +1,73 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#include "platform/platform.h"
+#include "T3D/decal/decalInstance.h"
+#include "scene/sceneRenderState.h"
+
+void DecalInstance::getWorldMatrix( MatrixF *outMat, bool flip )
+{
+   outMat->setPosition( mPosition );
+
+   Point3F fvec;
+   mCross( mNormal, mTangent, &fvec );
+
+   outMat->setColumn( 0, mTangent );
+   outMat->setColumn( 1, fvec );
+   outMat->setColumn( 2, mNormal );
+}
+
+F32 DecalInstance::calcPixelSize( U32 viewportHeight, const Point3F &cameraPos, F32 worldToScreenScaleY ) const
+{  
+   // If fadeStartPixelSize is set less than zero this is interpreted to mean
+   // pixelSize based fading is disabled and the decal always renders.
+   // Returning a value of F32_MAX should be treated by the caller as
+   // meaning "big enough to render at normal quality, dont LOD me.".
+   if ( mDataBlock->fadeStartPixelSize < 0.0f )
+      return F32_MAX;
+
+   // This is an approximation since mSize is actually the xyz size of the
+   // cube we use to clip geometry for the decal. In this case we are assuming
+   // it is appropriate to use the radius of the sphere 'inscribed' in that
+   // cube as the equivalent of mShape->radius for purposes of calculating
+   // the pixelScale ( see TSShapeInstance::setDetailFromDistance ).
+   const F32 radius = mSize * 0.5f;
+
+   // Approximate distance to the decal.    
+   const F32 distance = ( cameraPos - mPosition ).len() - radius;
+
+   // We are inside the decal's volume. There is no useful pixelSize for us
+   // to return, it is essentially the entire screen.
+   if ( distance <= 0.0f )
+      return F32_MAX;
+
+   // Lod is relative to a viewport with a heigh of 300.  Could prescale this into decalSize...
+   const F32 pixelScale = viewportHeight / 300.0f;
+
+   // Inline of SceneState::projectRadius.
+   const F32 pixelSize = mSize / distance * worldToScreenScaleY * pixelScale;
+
+   // Optionally scale pixelSize by a detail adjust value here...
+   // eg. pixelSize *= TSDetailAdjust...
+
+   return pixelSize;
+}