internal static bool CollideCircleLine(ICollidible circleCollidible1, CollisionTypeCircle cTypeCircle1, CollisionTypeLine cTypeLine)
{
// calculate the length of the perpendicular line from the line to the center of the circle
CCPoint vectorPerpToLine = CCPoint.PerpendicularCCW((cTypeLine.EndPoint - cTypeLine.StartPoint));
CCPoint vectorLineStartToCircle = ((CCNode)circleCollidible1).PositionWorldspace - cTypeLine.StartPoint;
float perpLength = (float)Math.Abs(CCPoint.Dot(vectorPerpToLine, vectorLineStartToCircle) / vectorPerpToLine.Length);
return(perpLength <= CorrectRadius(circleCollidible1, cTypeCircle1));
}
internal static bool CollideCircleCircle(ICollidible circleCollidible1, CollisionTypeCircle cTypeCircle1, ICollidible circleCollidible2, CollisionTypeCircle cTypeCircle2)
{
CCPoint pos1 = ((CCNode)circleCollidible1).PositionWorldspace;
CCPoint pos2 = ((CCNode)circleCollidible2).PositionWorldspace;
float radius1 = CorrectRadius(circleCollidible1, cTypeCircle1);
float radius2 = CorrectRadius(circleCollidible2, cTypeCircle2);
return(pos1.IsNear(pos2, radius1 + radius2));
}
// is dirty, as it only checks whether polygon points are contained in the circle, not whether polygon lines are crossed by it
internal static bool CollideCirclePolygon(ICollidible circleCollidible, CollisionTypeCircle cTypeCircle, ICollidible polyCollidible, CollisionTypePolygon cTypePoly)
{
float radius = CorrectRadius(circleCollidible, cTypeCircle);
CCPoint pos = ((CCNode)circleCollidible).PositionWorldspace;
// transform the polygon to match the positioning, rotation and scale of the node
Polygon transformedPolygon = ((Polygon)cTypePoly.collisionPolygon.Clone());
transformedPolygon.TransformAccordingToGameObject(polyCollidible);
// for each point of the polygon check whether its contained in the circle
foreach (var point in transformedPolygon.Points)
{
if (point.IsNear(pos, radius))
{
return(true);
}
}
return(false);
}
// exact
internal static bool CollideDiamondCircle(ICollidible collidibleDiamond, ICollidible collidibleCircle, CollisionTypeCircle cTypeCircle)
{
var circlePos = ((CCNode)collidibleCircle).PositionWorldspace;
var radius = CorrectRadius(collidibleCircle, cTypeCircle);
// for performance first check whether they are too far to collide anyway
var diamondBox = ((CCNode)collidibleDiamond).BoundingBoxTransformedToWorld;
float maxSizeBox = diamondBox.Size.Width > diamondBox.Size.Height ? diamondBox.Size.Width : diamondBox.Size.Height;
if (Math.Abs(circlePos.X - diamondBox.Center.X) > radius + diamondBox.Size.Width / 2 ||
Math.Abs(circlePos.Y - diamondBox.Center.Y) > radius + diamondBox.Size.Height / 2)
{
return(false);
}
var diamond = BoxToDiamond(diamondBox);
int i, j;
for (i = 0, j = diamond.Length - 1; i < diamond.Length; j = i++)
{
if (CollideCircleLine(circlePos, radius, diamond[i], diamond[j]))
{
return(true);
}
}
return(false);
}
internal static bool CollideBoundingBoxCircle(ICollidible boxCollidible, ICollidible circleCollidible, CollisionTypeCircle cTypeCircle)
{
return(CollideBoundingBoxCircle(((CCNode)boxCollidible).BoundingBoxTransformedToWorld, ((CCNode)circleCollidible).PositionWorldspace, CorrectRadius(circleCollidible, cTypeCircle)));
}
internal static bool CollidePositionCircle(ICollidible posCollidible, ICollidible circleCollidible, CollisionTypeCircle cTypeCircle)
{
return(((CCNode)circleCollidible).PositionWorldspace.IsNear(((CCNode)posCollidible).PositionWorldspace, CorrectRadius(circleCollidible, cTypeCircle)));
}
internal static float CorrectRadius(ICollidible circleCollidible, CollisionTypeCircle cTypeCircle)
{
return((cTypeCircle.useScale ? circleCollidible.GetTotalScale() : 1f) * cTypeCircle.radius);
}
