public static DistanceConstraint CreateJoint(this World world, Vertex v0, Vertex v1)
{
var constraint = new DistanceConstraint(
v0,
v1,
false
);
world.AddGlobalConstraint(constraint);
return(constraint);
}
public static bool CheckCollide(Body b0, Body b1)
{
if (
!(0 > Mathf.Abs(b1.center.x - b0.center.x) - (b1.halfExtent.x + b0.halfExtent.x) &&
0 > Mathf.Abs(b1.center.y - b0.center.y) - (b1.halfExtent.y + b0.halfExtent.y))
)
{
return(false); // no aabb overlap
}
var minDistance = float.MaxValue;
var n0 = b0.edges.Length;
var n1 = b1.edges.Length;
var dist = float.MaxValue;
// Iterate through all of the edges of both bodies
for (var i = 0; i < n1 + n0; i++)
{
// get edge
var edge = i < n0 ? b0.edges[i] : b1.edges[i - n0];
// Calculate the perpendicular to this edge and normalize it
m_TestAxis = MathUtils.Normal(edge.v0.position, edge.v1.position);
// Project both bodies onto the normal
b0.ProjectAxis(m_TestAxis);
b1.ProjectAxis(m_TestAxis);
//Calculate the distance between the two intervals
dist = b0.min < b1.min ? b1.min - b0.max : b0.min - b1.max;
// If the intervals don't overlap, return, since there is no collision
if (dist > 0)
{
return(false);
}
else if (Mathf.Abs(dist) < minDistance)
{
minDistance = Mathf.Abs(dist);
// Save collision information
m_Axis = m_TestAxis;
m_Edge = edge;
}
}
m_Depth = minDistance;
// Ensure collision edge in B1 and collision vertex in B0
if (m_Edge.parent != b1)
{
var t = b1;
b1 = b0;
b0 = t;
}
// Make sure that the collision normal is pointing at B1
m_Center = b0.center - b1.center;
var n = Vector2.Dot(m_Center, m_Axis);
// Revert the collision normal if it points away from B1
if (n < 0)
{
m_Axis = MathUtils.Neg(m_Axis);
}
var smallestDist = float.MaxValue;
for (var i = 0; i < b0.vertices.Length; i++)
{
// Measure the distance of the vertex from the line using the line equation
var v = b0.vertices[i];
m_Line = v.position - b1.center;
dist = Vector2.Dot(m_Axis, m_Line);
// Set the smallest distance and the collision vertex
if (dist < smallestDist)
{
smallestDist = dist;
m_Vertex = v;
}
}
m_Body = b0;
// There is no separating axis. Report a collision!
return(true);
}