private bool CheckShapeIntersection(Vector2 posA, float cosA, float sinA, float scaleA, CollisionShape shapeA,
Vector2 posB, float cosB, float sinB, float scaleB, CollisionShape shapeB)
{
CircleCollisionShape circleA = shapeA as CircleCollisionShape;
PolygonCollisionShape polygonA = shapeA as PolygonCollisionShape;
CircleCollisionShape circleB = shapeB as CircleCollisionShape;
PolygonCollisionShape polygonB = shapeB as PolygonCollisionShape;
if (circleA != null && circleB != null)
{
return(CheckCircleCircleIntersection(posA, circleA,
posB, circleB));
}
if (circleB != null && polygonA != null)
{
return(CheckPolygonCircleIntersection(posA, cosA, sinA, scaleA, polygonA,
posB, circleB));
}
if (circleA != null && polygonB != null)
{
return(CheckPolygonCircleIntersection(posB, cosB, sinB, scaleB, polygonB,
posA, circleA));
}
if (polygonA != null && polygonB != null)
{
return(CheckPolygonPolygonIntersection(posA, cosA, sinA, scaleA, polygonA,
posB, cosB, sinB, scaleB, polygonB));
}
return(false);
}
private bool CheckPolygonCircleIntersection(Vector2 posA, float cosA, float sinA, float scaleA, PolygonCollisionShape polygonA,
Vector2 posB, CircleCollisionShape circleB)
{
Vector2[] worldPolyA = new Vector2[polygonA.Vertices.Length];
for (int i = 0; i < polygonA.Vertices.Length; i++)
{
worldPolyA[i] = new Vector2(cosA * polygonA.Vertices[i].X - sinA * polygonA.Vertices[i].Y,
sinA * polygonA.Vertices[i].X + cosA * polygonA.Vertices[i].Y) * scaleA + posA;
}
BoundingCircle worldCircleB = new BoundingCircle(posB, circleB.Radius);
for (int i = 0; i < worldPolyA.Length; i++)
{
int j = (i + 1) % worldPolyA.Length;
Vector2 v1 = worldPolyA[j];
Vector2 v2 = worldPolyA[i];
// Check vertices; guarenteed to intersect if vertices
// are contained and less expensive than a segment intersection
// test.
if (worldCircleB.Contains(v1) || worldCircleB.Contains(v2))
{
return(true);
}
// Cast circle position onto segment
Vector2 segment = v2 - v1;
float circleOnSegment = Vector2.Dot(segment, worldCircleB.Position);
// Make sure segment is along the segment
if (circleOnSegment < 0)
{
continue;
}
if (circleOnSegment * circleOnSegment > segment.LengthSquared())
{
continue;
}
// Find point along segment
segment.Normalize();
Vector2 intersectionPoint = segment * circleOnSegment + v1;
// Check for intersection of intersection point
if (worldCircleB.Contains(intersectionPoint))
{
return(true);
}
}
return(false);
}
private bool CheckCircleCircleIntersection(Vector2 posA, CircleCollisionShape circleA,
Vector2 posB, CircleCollisionShape circleB)
{
return((posB - posA).LengthSquared() < circleB.RadiusSquared + circleA.RadiusSquared);
}
public void Draw(Matrix transformMatrix, float dt)
{
SpriteBatch.Begin(SpriteSortMode.Deferred,
BlendState.Opaque,
SamplerState.PointClamp,
null,
null,
null,
transformMatrix);
foreach (Entity entity in _collisionEntities)
{
CollisionComponent collisionComp = entity.GetComponent <CollisionComponent>();
TransformComponent transformComp = entity.GetComponent <TransformComponent>();
Vector2 position = transformComp.Position * FlipY;
float cos = (float)Math.Cos(-transformComp.Rotation);
float sin = (float)Math.Sin(-transformComp.Rotation);
float scale = transformComp.Scale;
foreach (CollisionShape shape in collisionComp.CollisionShapes)
{
Vector2 rotatedOffset = rotateAroundOrigin(shape.Offset, cos, sin);
BoundingRect AABB = shape.GetAABB(cos, sin, scale);
AABB.Min += position;
AABB.Max += position;
SpriteBatch.DrawRectangle(new Rectangle((int)AABB.Left,
(int)AABB.Bottom,
(int)AABB.Width,
(int)AABB.Height),
Color.BlueViolet,
1);
CircleCollisionShape circleCollisionShape = shape as CircleCollisionShape;
if (circleCollisionShape != null)
{
SpriteBatch.DrawCircle(position + rotatedOffset * scale,
circleCollisionShape.Radius * scale,
25,
Color.YellowGreen);
}
PolygonCollisionShape polygonCollisionShape = shape as PolygonCollisionShape;
if (polygonCollisionShape != null)
{
for (int i = 0; i < polygonCollisionShape.Vertices.Length; i++)
{
Vector2 v1 = polygonCollisionShape.Vertices[i] * FlipY;
Vector2 v2 = polygonCollisionShape.Vertices[(i + 1) % polygonCollisionShape.Vertices.Length] * FlipY;
SpriteBatch.DrawLine(position + (rotatedOffset + rotateAroundOrigin(v1, cos, sin)) * scale,
position + (rotatedOffset + rotateAroundOrigin(v2, cos, sin)) * scale,
Color.YellowGreen);
}
}
}
}
SpriteBatch.End();
}
