// static
BoundingBox3f BoundingBox3f::unite( const BoundingBox3f& b0, const BoundingBox3f& b1 )
{
Vector3f b0Min = b0.minimum();
Vector3f b0Max = b0.maximum();
Vector3f b1Min = b1.minimum();
Vector3f b1Max = b1.maximum();
Vector3f newMin( min( b0Min.x, b1Min.x ), min( b0Min.y, b1Min.y ), min( b0Min.z, b1Min.z ) );
Vector3f newMax( max( b0Max.x, b1Max.x ), max( b0Max.y, b1Max.y ), max( b0Max.z, b1Max.z ) );
return BoundingBox3f( newMin, newMax );
}
// static
BoundingBox3f BoundingBox3f::intersect( const BoundingBox3f& b0, const BoundingBox3f& b1 )
{
Vector3f b0Min = b0.minimum();
Vector3f b0Max = b0.maximum();
Vector3f b1Min = b1.minimum();
Vector3f b1Max = b1.maximum();
Vector3f newMin( max( b0Min.x, b1Min.x ), max( b0Min.y, b1Min.y ), max( b0Min.z, b1Min.z ) );
Vector3f newMax( min( b0Max.x, b1Max.x ), min( b0Max.y, b1Max.y ), min( b0Max.z, b1Max.z ) );
for(int i = 0; i < 3; ++i)
newMax[i] = max(newMax[i], newMin[i]);
return BoundingBox3f( newMin, newMax );
}
bool BoundingBox3f::overlaps( const BoundingBox3f& other )
{
bool bOverlapsInDirection[3];
Vector3f otherMin = other.minimum();
Vector3f otherMax = other.maximum();
for( int i = 0; i < 3; ++i )
{
bool bMinInside0 = ( otherMin[i] >= m_min[i] ) && ( otherMin[i] <= m_max[i] );
bool bMinInside1 = ( m_min[i] >= otherMin[i] ) && ( m_min[i] <= otherMax[i] );
bool bMaxInside0 = ( otherMax[i] >= m_min[i] ) && ( otherMax[i] <= m_max[i] );
bool bMaxInside1 = ( m_max[i] >= otherMin[i] ) && ( m_max[i] <= otherMax[i] );
bool bMinInside = bMinInside0 || bMinInside1;
bool bMaxInside = bMaxInside0 || bMaxInside1;
bOverlapsInDirection[i] = bMinInside || bMaxInside;
}
return bOverlapsInDirection[0] && bOverlapsInDirection[1] && bOverlapsInDirection[2];
}
// virtual
Matrix4f DirectionalLight::lightMatrix( const Camera& camera, const BoundingBox3f& sceneBoundingBox )
{
const float feather = 1.01;
Matrix3f lightLinear = lightBasis();
Vector3f eye = camera.getEye();
// get the corners of the view frustum in light coordinates
// with the z = 0 plane at the eye
QVector< Vector3f > frustumCorners = camera.getFrustumCorners();
BoundingBox3f frustumBB;
for( int i = 0; i < frustumCorners.size(); ++i )
frustumBB.enlarge(frustumCorners[i]);
BoundingBox3f sceneAndFrustum = BoundingBox3f::intersect(frustumBB, sceneBoundingBox);
QVector< Vector3f > sceneCorners = sceneBoundingBox.corners();
QVector< Vector3f > sceneAndFrustumCorners = sceneAndFrustum.corners();
for( int i = 0; i < sceneAndFrustumCorners.size(); ++i )
{
sceneAndFrustumCorners[ i ] = lightLinear * ( sceneAndFrustumCorners[ i ] - eye );
sceneCorners[ i ] = lightLinear * ( sceneCorners[ i ] - eye );
}
BoundingBox3f inLightCoordinates;
for(int i = 0; i < sceneAndFrustumCorners.size(); ++i)
inLightCoordinates.enlarge(sceneAndFrustumCorners[i]);
Vector3f maxCorner = inLightCoordinates.maximum();
Vector3f minCorner = inLightCoordinates.minimum();
Vector3f center = inLightCoordinates.center();
maxCorner = center + feather * (maxCorner - center);
minCorner = center + feather * (minCorner - center);
// add eye point
for(int j = 0; j < 3; ++j)
{
maxCorner[j] = qMax( maxCorner[ j ], 0.0f );
minCorner[j] = qMin( minCorner[ j ], 0.0f );
}
// bound the near plane to the scene
for( int i = 0; i < sceneCorners.size(); ++i )
{
minCorner[2] = qMin( minCorner[2], sceneCorners[ i ][ 2 ] );
}
// finally, compute the full light matrix
Matrix4f lightMatrix;
lightMatrix.setSubmatrix3x3( 0, 0, lightLinear );
Vector3f origin = 0.5 * ( minCorner + maxCorner );
origin[2] = minCorner[2];
lightMatrix.setCol( 3, Vector4f( -origin, 1.f ) - Vector4f( lightLinear * eye, 0.f ) );
for(int i = 0; i < 3; ++i)
{
lightMatrix.setRow( i, lightMatrix.getRow( i ) * ( ( i == 2 ) ? 1.f : 2.f ) / ( maxCorner[i] - minCorner[i] ) );
}
return lightMatrix;
}
