/*
============
idWinding2D::LineIntersection
============
*/
bool idWinding2D::LineIntersection( const idVec2 &start, const idVec2 &end ) const {
int i, numEdges;
int sides[MAX_POINTS_ON_WINDING_2D+1], counts[3];
float d1, d2, epsilon = 0.1f;
idVec3 plane, edges[2];
counts[SIDE_FRONT] = counts[SIDE_BACK] = counts[SIDE_ON] = 0;
plane = Plane2DFromPoints( start, end );
for ( i = 0; i < numPoints; i++ ) {
d1 = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if ( d1 > epsilon ) {
sides[i] = SIDE_FRONT;
}
else if ( d1 < -epsilon ) {
sides[i] = SIDE_BACK;
}
else {
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
if ( !counts[SIDE_FRONT] ) {
return false;
}
if ( !counts[SIDE_BACK] ) {
return false;
}
numEdges = 0;
for ( i = 0; i < numPoints; i++ ) {
if ( sides[i] != sides[i+1] && sides[i+1] != SIDE_ON ) {
edges[numEdges++] = Plane2DFromPoints( p[i], p[(i+1)%numPoints] );
if ( numEdges >= 2 ) {
break;
}
}
}
if ( numEdges < 2 ) {
return false;
}
d1 = edges[0].x * start.x + edges[0].y * start.y + edges[0].z;
d2 = edges[0].x * end.x + edges[0].y * end.y + edges[0].z;
if ( FLOATSIGNBITNOTSET( d1 ) & FLOATSIGNBITNOTSET( d2 ) ) {
return false;
}
d1 = edges[1].x * start.x + edges[1].y * start.y + edges[1].z;
d2 = edges[1].x * end.x + edges[1].y * end.y + edges[1].z;
if ( FLOATSIGNBITNOTSET( d1 ) & FLOATSIGNBITNOTSET( d2 ) ) {
return false;
}
return true;
}
/*
============
idWinding2D::PointInside
============
*/
bool idWinding2D::PointInside( const idVec2 &point, const float epsilon ) const {
int i;
float d;
idVec3 plane;
for ( i = 0; i < numPoints; i++ ) {
plane = Plane2DFromPoints( p[i], p[(i+1) % numPoints] );
d = plane.x * point.x + plane.y * point.y + plane.z;
if ( d > epsilon ) {
return false;
}
}
return true;
}
/*
============
idWinding2D::ExpandForAxialBox
============
*/
void idWinding2D::ExpandForAxialBox( const idVec2 bounds[2] ) {
int i, j, numPlanes;
idVec2 v;
idVec3 planes[MAX_POINTS_ON_WINDING_2D], plane, bevel;
// get planes for the edges and add bevels
for ( numPlanes = i = 0; i < numPoints; i++ ) {
j = (i+1) % numPoints;
if ( ( p[j] - p[i] ).LengthSqr() < 0.01f ) {
continue;
}
plane = Plane2DFromPoints( p[i], p[j], true );
if ( i ) {
if ( GetAxialBevel( planes[numPlanes-1], plane, p[i], bevel ) ) {
planes[numPlanes++] = bevel;
}
}
assert( numPlanes < MAX_POINTS_ON_WINDING_2D );
planes[numPlanes++] = plane;
}
assert( numPlanes < MAX_POINTS_ON_WINDING_2D && numPlanes > 0 );
if ( GetAxialBevel( planes[numPlanes-1], planes[0], p[0], bevel ) ) {
planes[numPlanes++] = bevel;
}
// expand the planes
for ( i = 0; i < numPlanes; i++ ) {
v.x = bounds[ IEEE_FLT_SIGNBITSET( planes[i].x ) ].x;
v.y = bounds[ IEEE_FLT_SIGNBITSET( planes[i].y ) ].y;
planes[i].z += v.x * planes[i].x + v.y * planes[i].y;
}
// get intersection points of the planes
for ( numPoints = i = 0; i < numPlanes; i++ ) {
if ( Plane2DIntersection( planes[(i+numPlanes-1) % numPlanes], planes[i], p[numPoints] ) ) {
numPoints++;
}
}
}
/*
============
idWinding2D::RayIntersection
============
*/
bool idWinding2D::RayIntersection( const idVec2 &start, const idVec2 &dir, float &scale1, float &scale2, int *edgeNums ) const {
int i, numEdges, localEdgeNums[2];
int sides[MAX_POINTS_ON_WINDING_2D+1], counts[3];
float d1, d2, epsilon = 0.1f;
idVec3 plane, edges[2];
scale1 = scale2 = 0.0f;
counts[SIDE_FRONT] = counts[SIDE_BACK] = counts[SIDE_ON] = 0;
plane = Plane2DFromVecs( start, dir );
for ( i = 0; i < numPoints; i++ ) {
d1 = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if ( d1 > epsilon ) {
sides[i] = SIDE_FRONT;
}
else if ( d1 < -epsilon ) {
sides[i] = SIDE_BACK;
}
else {
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
if ( !counts[SIDE_FRONT] ) {
return false;
}
if ( !counts[SIDE_BACK] ) {
return false;
}
numEdges = 0;
for ( i = 0; i < numPoints; i++ ) {
if ( sides[i] != sides[i+1] && sides[i+1] != SIDE_ON ) {
localEdgeNums[numEdges] = i;
edges[numEdges++] = Plane2DFromPoints( p[i], p[(i+1)%numPoints] );
if ( numEdges >= 2 ) {
break;
}
}
}
if ( numEdges < 2 ) {
return false;
}
d1 = edges[0].x * start.x + edges[0].y * start.y + edges[0].z;
d2 = - ( edges[0].x * dir.x + edges[0].y * dir.y );
if ( d2 == 0.0f ) {
return false;
}
scale1 = d1 / d2;
d1 = edges[1].x * start.x + edges[1].y * start.y + edges[1].z;
d2 = - ( edges[1].x * dir.x + edges[1].y * dir.y );
if ( d2 == 0.0f ) {
return false;
}
scale2 = d1 / d2;
if ( idMath::Fabs( scale1 ) > idMath::Fabs( scale2 ) ) {
idSwap( scale1, scale2 );
idSwap( localEdgeNums[0], localEdgeNums[1] );
}
if ( edgeNums ) {
edgeNums[0] = localEdgeNums[0];
edgeNums[1] = localEdgeNums[1];
}
return true;
}
