354 lines
13 KiB
C++
354 lines
13 KiB
C++
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/****************************************************************************
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Copyright (c) 2011-2013,WebJet Business Division,CYOU
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http://www.genesis-3d.com.cn
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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****************************************************************************/
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#include "stdneb.h"
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#include "shadowmaputil.h"
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#include "math/frustum.h"
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namespace AppUtil
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{
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void ShadowMapUtil::CalculateAABBPoints(Math::float4* aabbPoints, const Math::float4& sceneCenter, const Math::float4& sceneExtends)
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{
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//This map enables us to use a for loop and do vector math.
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static const Math::float4 vExtentsMap[8] =
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{
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Math::float4(1.0f, 1.0f, -1.0f, 1.0f),
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Math::float4(-1.0f, 1.0f, -1.0f, 1.0f),
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Math::float4(1.0f, -1.0f, -1.0f, 1.0f),
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Math::float4(-1.0f, -1.0f, -1.0f, 1.0f),
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Math::float4(1.0f, 1.0f, 1.0f, 1.0f),
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Math::float4(-1.0f, 1.0f, 1.0f, 1.0f),
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Math::float4(1.0f, -1.0f, 1.0f, 1.0f),
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Math::float4(-1.0f, -1.0f, 1.0f, 1.0f)
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};
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for( IndexT index = 0; index < 8; ++index )
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{
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aabbPoints[index] = Math::float4::multiply(vExtentsMap[index], sceneExtends) + sceneCenter;
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}
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}
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void ShadowMapUtil::CreateFrustumPointsFromCascadeInterval(float fCascadeIntervalBegin, float fCascadeIntervalEnd, const Math::matrix44 &vProjection,Math::float4* pvCornerPointsWorld)
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{
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Math::frustum::ComputeFrustumFromProjection( pvCornerPointsWorld,fCascadeIntervalBegin,fCascadeIntervalEnd, vProjection, 0.0f != vProjection.mx[3][2]);
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}
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// From DX SDK
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void ShadowMapUtil::ComputeNearAndFar( float& fNearPlane, float& fFarPlane, Math::float4 vLightCameraOrthographicMin, Math::float4 vLightCameraOrthographicMax, Math::float4* pvPointsInCameraView )
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{
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//--------------------------------------------------------------------------------------
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// Used to compute an intersection of the orthographic projection and the Scene AABB
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//--------------------------------------------------------------------------------------
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struct Triangle
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{
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Math::float4 pt[3];
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bool culled;
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};
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// Initialize the near and far planes
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fNearPlane = S_C_FLOAT4MAX.x();
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fFarPlane = -S_C_FLOAT4MAX.x();
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Triangle triangleList[16];
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IndexT iTriangleCnt = 1;
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triangleList[0].pt[0] = pvPointsInCameraView[0];
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triangleList[0].pt[1] = pvPointsInCameraView[1];
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triangleList[0].pt[2] = pvPointsInCameraView[2];
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triangleList[0].culled = false;
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// These are the indices used to tesselate an AABB into a list of triangles.
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static const IndexT iAABBTriIndexes[] =
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{
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0,1,2, 1,2,3,
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4,5,6, 5,6,7,
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0,2,4, 2,4,6,
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1,3,5, 3,5,7,
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0,1,4, 1,4,5,
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2,3,6, 3,6,7
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};
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IndexT iPointPassesCollision[3];
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// At a high level:
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// 1. Iterate over all 12 triangles of the AABB.
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// 2. Clip the triangles against each plane. Create new triangles as needed.
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// 3. Find the min and max z values as the near and far plane.
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//This is easier because the triangles are in camera spacing making the collisions tests simple comparisions.
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float fLightCameraOrthographicMinX = vLightCameraOrthographicMin.x();
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float fLightCameraOrthographicMaxX = vLightCameraOrthographicMax.x();
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float fLightCameraOrthographicMinY = vLightCameraOrthographicMin.x();
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float fLightCameraOrthographicMaxY = vLightCameraOrthographicMax.x();
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for( IndexT AABBTriIter = 0; AABBTriIter < 12; ++AABBTriIter )
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{
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triangleList[0].pt[0] = pvPointsInCameraView[ iAABBTriIndexes[ AABBTriIter*3 + 0 ] ];
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triangleList[0].pt[1] = pvPointsInCameraView[ iAABBTriIndexes[ AABBTriIter*3 + 1 ] ];
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triangleList[0].pt[2] = pvPointsInCameraView[ iAABBTriIndexes[ AABBTriIter*3 + 2 ] ];
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iTriangleCnt = 1;
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triangleList[0].culled = false;
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// Clip each invidual triangle against the 4 frustums. When ever a triangle is clipped into new triangles,
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//add them to the list.
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for( IndexT frustumPlaneIter = 0; frustumPlaneIter < 4; ++frustumPlaneIter )
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{
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Math::scalar fEdge;
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IndexT iComponent;
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if( frustumPlaneIter == 0 )
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{
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fEdge = fLightCameraOrthographicMinX; // todo make float temp
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iComponent = 0;
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}
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else if( frustumPlaneIter == 1 )
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{
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fEdge = fLightCameraOrthographicMaxX;
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iComponent = 0;
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}
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else if( frustumPlaneIter == 2 )
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{
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fEdge = fLightCameraOrthographicMinY;
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iComponent = 1;
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}
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else
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{
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fEdge = fLightCameraOrthographicMaxY;
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iComponent = 1;
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}
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for( IndexT triIter=0; triIter < iTriangleCnt; ++triIter )
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{
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// We don't delete triangles, so we skip those that have been culled.
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if( !triangleList[triIter].culled )
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{
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IndexT iInsideVertCount = 0;
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Math::float4 tempOrder;
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// Test against the correct frustum plane.
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// This could be written more compactly, but it would be harder to understand.
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if( frustumPlaneIter == 0 )
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{
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for( IndexT triPtIter=0; triPtIter < 3; ++triPtIter )
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{
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if( triangleList[triIter].pt[triPtIter].x() >
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vLightCameraOrthographicMin.x() )
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{
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iPointPassesCollision[triPtIter] = 1;
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}
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else
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{
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iPointPassesCollision[triPtIter] = 0;
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}
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iInsideVertCount += iPointPassesCollision[triPtIter];
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}
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}
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else if( frustumPlaneIter == 1 )
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{
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for( IndexT triPtIter=0; triPtIter < 3; ++triPtIter )
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{
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if( triangleList[triIter].pt[triPtIter].x() <
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vLightCameraOrthographicMax.x() )
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{
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iPointPassesCollision[triPtIter] = 1;
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}
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else
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{
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iPointPassesCollision[triPtIter] = 0;
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}
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iInsideVertCount += iPointPassesCollision[triPtIter];
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}
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}
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else if( frustumPlaneIter == 2 )
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{
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for( IndexT triPtIter=0; triPtIter < 3; ++triPtIter )
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{
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if( triangleList[triIter].pt[triPtIter].y() >
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vLightCameraOrthographicMin.y() )
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{
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iPointPassesCollision[triPtIter] = 1;
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}
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else
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{
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iPointPassesCollision[triPtIter] = 0;
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}
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iInsideVertCount += iPointPassesCollision[triPtIter];
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}
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}
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else
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{
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for( IndexT triPtIter=0; triPtIter < 3; ++triPtIter )
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{
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if( triangleList[triIter].pt[triPtIter].y() <
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vLightCameraOrthographicMax.y() )
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{
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iPointPassesCollision[triPtIter] = 1;
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}
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else
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{
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iPointPassesCollision[triPtIter] = 0;
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}
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iInsideVertCount += iPointPassesCollision[triPtIter];
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}
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}
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// Move the points that pass the frustum test to the begining of the array.
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if( iPointPassesCollision[1] && !iPointPassesCollision[0] )
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{
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tempOrder = triangleList[triIter].pt[0];
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triangleList[triIter].pt[0] = triangleList[triIter].pt[1];
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triangleList[triIter].pt[1] = tempOrder;
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iPointPassesCollision[0] = 1;
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iPointPassesCollision[1] = 0;
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}
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if( iPointPassesCollision[2] && !iPointPassesCollision[1] )
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{
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tempOrder = triangleList[triIter].pt[1];
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triangleList[triIter].pt[1] = triangleList[triIter].pt[2];
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triangleList[triIter].pt[2] = tempOrder;
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iPointPassesCollision[1] = 1;
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iPointPassesCollision[2] = 0;
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}
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if( iPointPassesCollision[1] && !iPointPassesCollision[0] )
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{
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tempOrder = triangleList[triIter].pt[0];
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triangleList[triIter].pt[0] = triangleList[triIter].pt[1];
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triangleList[triIter].pt[1] = tempOrder;
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iPointPassesCollision[0] = 1;
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iPointPassesCollision[1] = 0;
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}
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if( iInsideVertCount == 0 )
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{ // All points failed. We're done,
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triangleList[triIter].culled = true;
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}
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else if( iInsideVertCount == 1 )
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{// One point passed. Clip the triangle against the Frustum plane
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triangleList[triIter].culled = false;
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//
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Math::float4 vVert0ToVert1 = triangleList[triIter].pt[1] - triangleList[triIter].pt[0];
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Math::float4 vVert0ToVert2 = triangleList[triIter].pt[2] - triangleList[triIter].pt[0];
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// Find the collision ratio.
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Math::scalar fHitPointTimeRatio = fEdge - triangleList[triIter].pt[0][iComponent] ;
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// Calculate the distance along the vector as ratio of the hit ratio to the component.
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Math::scalar fDistanceAlongVector01 = fHitPointTimeRatio / vVert0ToVert1[iComponent];
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Math::scalar fDistanceAlongVector02 = fHitPointTimeRatio / vVert0ToVert2[iComponent];
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// Add the point plus a percentage of the vector.
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vVert0ToVert1 *= fDistanceAlongVector01;
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vVert0ToVert1 += triangleList[triIter].pt[0];
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vVert0ToVert2 *= fDistanceAlongVector02;
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vVert0ToVert2 += triangleList[triIter].pt[0];
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triangleList[triIter].pt[1] = vVert0ToVert2;
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triangleList[triIter].pt[2] = vVert0ToVert1;
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}
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else if( iInsideVertCount == 2 )
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{ // 2 in // tesselate into 2 triangles
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// Copy the triangle\(if it exists) after the current triangle out of
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// the way so we can override it with the new triangle we're inserting.
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triangleList[iTriangleCnt] = triangleList[triIter+1];
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triangleList[triIter].culled = false;
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triangleList[triIter+1].culled = false;
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// Get the vector from the outside point into the 2 inside points.
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Math::float4 vVert2ToVert0 = triangleList[triIter].pt[0] - triangleList[triIter].pt[2];
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Math::float4 vVert2ToVert1 = triangleList[triIter].pt[1] - triangleList[triIter].pt[2];
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// Get the hit point ratio.
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Math::scalar fHitPointTime_2_0 = fEdge - triangleList[triIter].pt[2][iComponent];
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Math::scalar fDistanceAlongVector_2_0 = fHitPointTime_2_0 / vVert2ToVert0[iComponent];
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// Calcaulte the new vert by adding the percentage of the vector plus point 2.
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vVert2ToVert0 *= fDistanceAlongVector_2_0;
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vVert2ToVert0 += triangleList[triIter].pt[2];
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// Add a new triangle.
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triangleList[triIter+1].pt[0] = triangleList[triIter].pt[0];
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triangleList[triIter+1].pt[1] = triangleList[triIter].pt[1];
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triangleList[triIter+1].pt[2] = vVert2ToVert0;
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//Get the hit point ratio.
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Math::scalar fHitPointTime_2_1 = fEdge - triangleList[triIter].pt[2][iComponent];
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Math::scalar fDistanceAlongVector_2_1 = fHitPointTime_2_1 / vVert2ToVert1[iComponent];
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vVert2ToVert1 *= fDistanceAlongVector_2_1;
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vVert2ToVert1 += triangleList[triIter].pt[2];
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triangleList[triIter].pt[0] = triangleList[triIter+1].pt[1];
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triangleList[triIter].pt[1] = triangleList[triIter+1].pt[2];
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triangleList[triIter].pt[2] = vVert2ToVert1;
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// Cncrement triangle count and skip the triangle we just inserted.
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++iTriangleCnt;
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++triIter;
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}
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else
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{ // all in
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triangleList[triIter].culled = false;
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}
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}// end if !culled loop
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}
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}
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for( IndexT index=0; index < iTriangleCnt; ++index )
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{
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if( !triangleList[index].culled )
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{
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// Set the near and far plan and the min and max z values respectivly.
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for( int vertind = 0; vertind < 3; ++ vertind )
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{
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float fTriangleCoordZ = triangleList[index].pt[vertind].z();
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if( fNearPlane > fTriangleCoordZ )
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{
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fNearPlane = fTriangleCoordZ;
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}
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if( fFarPlane <fTriangleCoordZ )
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{
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fFarPlane = fTriangleCoordZ;
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}
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}
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}
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}
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}
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}
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void ShadowMapUtil::CalculateCloseSphereFromFrustum(const Math::float4 points[8], Math::float4& outCenter, float& outRadius)
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{
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Math::float4 halfFarLongVec = (points[0] - points[3]) * 0.5f;
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Math::float4 halfNearLongVec = (points[4] - points[7]) * 0.5f;
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float squareFarRadius = Math::float4::dot3(halfFarLongVec, halfFarLongVec);
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float squareNearRadius = Math::float4::dot3(halfNearLongVec, halfNearLongVec);
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float subZ = Math::n_abs( points[0].z() - points[4].z() );
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float offsetZNear = 0.5f * ((squareFarRadius - squareNearRadius) / subZ + subZ);
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float squareOffsetZNear = offsetZNear * offsetZNear;
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outCenter = Math::float4(0.0f, 0.0f, points[4].z() - offsetZNear, 1.0f);
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outRadius = Math::n_sqrt( squareOffsetZNear + squareNearRadius ) + 0.001f;
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}
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}
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