decalInstance.cpp

Engine/source/T3D/decal/decalInstance.cpp

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Detailed Description

 1
 2//-----------------------------------------------------------------------------
 3// Copyright (c) 2012 GarageGames, LLC
 4//
 5// Permission is hereby granted, free of charge, to any person obtaining a copy
 6// of this software and associated documentation files (the "Software"), to
 7// deal in the Software without restriction, including without limitation the
 8// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 9// sell copies of the Software, and to permit persons to whom the Software is
10// furnished to do so, subject to the following conditions:
11//
12// The above copyright notice and this permission notice shall be included in
13// all copies or substantial portions of the Software.
14//
15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21// IN THE SOFTWARE.
22//-----------------------------------------------------------------------------
23
24#include "platform/platform.h"
25#include "T3D/decal/decalInstance.h"
26#include "scene/sceneRenderState.h"
27
28DecalInstance::DecalInstance()
29   : mDataBlock(NULL),
30   mRotAroundNormal(0.0f),
31   mSize(0.0f),
32   mCreateTime(0),
33   mVisibility(1.0f),
34   mLastAlpha(1.0f),
35   mTextureRectIdx(0),
36   mVerts(NULL),
37   mIndices(NULL),
38   mVertCount(0),
39   mIndxCount(0),
40   mFlags(0),
41   mRenderPriority(0),
42   mId(-1),
43   mCustomTex(NULL)
44{}
45void DecalInstance::getWorldMatrix( MatrixF *outMat, bool flip )
46{
47   outMat->setPosition( mPosition );
48
49   Point3F fvec;
50   mCross( mNormal, mTangent, &fvec );
51
52   outMat->setColumn( 0, mTangent );
53   outMat->setColumn( 1, fvec );
54   outMat->setColumn( 2, mNormal );
55}
56
57F32 DecalInstance::calcPixelSize( U32 viewportHeight, const Point3F &cameraPos, F32 worldToScreenScaleY ) const
58{  
59   // If fadeStartPixelSize is set less than zero this is interpreted to mean
60   // pixelSize based fading is disabled and the decal always renders.
61   // Returning a value of F32_MAX should be treated by the caller as
62   // meaning "big enough to render at normal quality, dont LOD me.".
63   if ( mDataBlock->fadeStartPixelSize < 0.0f )
64      return F32_MAX;
65
66   // This is an approximation since mSize is actually the xyz size of the
67   // cube we use to clip geometry for the decal. In this case we are assuming
68   // it is appropriate to use the radius of the sphere 'inscribed' in that
69   // cube as the equivalent of mShape->radius for purposes of calculating
70   // the pixelScale ( see TSShapeInstance::setDetailFromDistance ).
71   const F32 radius = mSize * 0.5f;
72
73   // Approximate distance to the decal.    
74   const F32 distance = ( cameraPos - mPosition ).len() - radius;
75
76   // We are inside the decal's volume. There is no useful pixelSize for us
77   // to return, it is essentially the entire screen.
78   if ( distance <= 0.0f )
79      return F32_MAX;
80
81   // Lod is relative to a viewport with a heigh of 300.  Could prescale this into decalSize...
82   const F32 pixelScale = viewportHeight / 300.0f;
83
84   // Inline of SceneState::projectRadius.
85   const F32 pixelSize = mSize / distance * worldToScreenScaleY * pixelScale;
86
87   // Optionally scale pixelSize by a detail adjust value here...
88   // eg. pixelSize *= TSDetailAdjust...
89
90   return pixelSize;
91}
92