private static void HandleCollision(CollisionCircle circle1, CollisionCircle circle2)
{
if (circle1.IsStatic && circle2.IsStatic)
{
return;
}
Vector2 d = circle1.Center - circle2.Center;
float distance = d.Length();
// If two circles collide
if (circle1.Radius + circle2.Radius > distance)
{
if (distance == 0)
{
d.X = r.Next(-200, 201);
d.Y = r.Next(-200, 201);
if (d != Vector2.Zero)
{
d.Normalize();
}
}
else
{
d /= distance;
}
// Static objects do not move, so only move back the non-static one
if (circle1.IsStatic)
{
d *= -1;
float distToPush = circle1.Radius + circle2.Radius - distance + OFFSET;
circle2.Center += distToPush * d;
}
else if (circle2.IsStatic)
{
Vector2 direction = d / distance;
float distToPush = circle1.Radius + circle2.Radius - distance + OFFSET;
circle1.Center += distToPush * d;
}
// If both objects are non-static, move them both back evenly
else
{
float distToPush = (circle1.Radius + circle2.Radius - distance) / 2 + OFFSET;
circle1.Center += distToPush * d;
circle2.Center -= distToPush * d;
}
}
}
private static void HandleCollision(CollisionCircle circle, CollisionRect rect)
{
if(circle.IsStatic && rect.IsStatic)
return;
// Reference: stackoverflow.com/questions/401847/circle-rectangle-collision-detection-intersection/402010#402010
Vector2 d = circle.Center - rect.Center;
d = new Vector2(Math.Abs(d.X), Math.Abs(d.Y));
Vector2 cd = new Vector2(d.X - rect.Width * 0.5f, d.Y - rect.Depth * 0.5f);
float cornerDistSqr = cd.LengthSquared();
// If circle and rectangle collide
if(d.X <= rect.Width / 2 + circle.Radius && d.Y <= rect.Depth / 2 + circle.Radius
|| cornerDistSqr <= circle.Radius * circle.Radius) {
// If circle and rectangle centers completely overlap,
// slightly move one of the object's center so they don't completely overlap
if(d.Length() == 0) {
d.X = r.Next(-200, 201);
d.Y = r.Next(-200, 201);
if(d != Vector2.Zero) {
d.Normalize();
d *= 0.1f;
}
if(circle.IsStatic)
rect.Center += d;
else
circle.Center += d;
HandleCollision(circle, rect);
}
// Create a collision boundary around the rectangle, in which collision occurs
float top = rect.Center.Y + rect.Depth / 2 + circle.Radius;
float bottom = rect.Center.Y - rect.Depth / 2 - circle.Radius;
float left = rect.Center.X - rect.Width / 2 - circle.Radius;
float right = rect.Center.X + rect.Width / 2 + circle.Radius;
float distToTop = Math.Abs(circle.Center.Y - top);
float distToBottom = Math.Abs(circle.Center.Y - bottom);
float distToLeft = Math.Abs(circle.Center.X - left);
float distToRight = Math.Abs(circle.Center.X - right);
// Choose the closest distance to the collision boundary as the pushing direction
Vector2 pushAmount = new Vector2(); // How much should be pushed relative to circle
float min = Math.Min(Math.Min(Math.Min(distToTop, distToBottom), distToLeft), distToRight);
pushAmount.Y += min == distToTop ? distToTop + OFFSET : 0;
pushAmount.Y += min == distToBottom ? -distToBottom - OFFSET : 0;
pushAmount.X += min == distToLeft ? -distToLeft - OFFSET : 0;
pushAmount.X += min == distToRight ? distToRight + OFFSET : 0;
// Only move the non-static object
if(rect.IsStatic)
circle.Center += pushAmount;
else if(circle.IsStatic)
rect.Center -= pushAmount;
else {
circle.Center += pushAmount / 2;
rect.Center -= pushAmount / 2;
}
}
}
private static void HandleCollision(CollisionCircle circle1, CollisionCircle circle2)
{
if(circle1.IsStatic && circle2.IsStatic) return;
Vector2 d = circle1.Center - circle2.Center;
float distance = d.Length();
// If two circles collide
if(circle1.Radius + circle2.Radius > distance) {
if(distance == 0) {
d.X = r.Next(-200, 201);
d.Y = r.Next(-200, 201);
if(d != Vector2.Zero)
d.Normalize();
}
else {
d /= distance;
}
// Static objects do not move, so only move back the non-static one
if(circle1.IsStatic) {
d *= -1;
float distToPush = circle1.Radius + circle2.Radius - distance + OFFSET;
circle2.Center += distToPush * d;
}
else if(circle2.IsStatic) {
Vector2 direction = d / distance;
float distToPush = circle1.Radius + circle2.Radius - distance + OFFSET;
circle1.Center += distToPush * d;
}
// If both objects are non-static, move them both back evenly
else {
float distToPush = (circle1.Radius + circle2.Radius - distance) / 2 + OFFSET;
circle1.Center += distToPush * d;
circle2.Center -= distToPush * d;
}
}
}
private static void HandleCollision(CollisionCircle circle, CollisionRect rect)
{
if (circle.IsStatic && rect.IsStatic)
{
return;
}
// Reference: stackoverflow.com/questions/401847/circle-rectangle-collision-detection-intersection/402010#402010
Vector2 d = circle.Center - rect.Center;
d = new Vector2(Math.Abs(d.X), Math.Abs(d.Y));
Vector2 cd = new Vector2(d.X - rect.Width * 0.5f, d.Y - rect.Depth * 0.5f);
float cornerDistSqr = cd.LengthSquared();
// If circle and rectangle collide
if (d.X <= rect.Width / 2 + circle.Radius && d.Y <= rect.Depth / 2 + circle.Radius ||
cornerDistSqr <= circle.Radius * circle.Radius)
{
// If circle and rectangle centers completely overlap,
// slightly move one of the object's center so they don't completely overlap
if (d.Length() == 0)
{
d.X = r.Next(-200, 201);
d.Y = r.Next(-200, 201);
if (d != Vector2.Zero)
{
d.Normalize();
d *= 0.1f;
}
if (circle.IsStatic)
{
rect.Center += d;
}
else
{
circle.Center += d;
}
HandleCollision(circle, rect);
}
// Create a collision boundary around the rectangle, in which collision occurs
float top = rect.Center.Y + rect.Depth / 2 + circle.Radius;
float bottom = rect.Center.Y - rect.Depth / 2 - circle.Radius;
float left = rect.Center.X - rect.Width / 2 - circle.Radius;
float right = rect.Center.X + rect.Width / 2 + circle.Radius;
float distToTop = Math.Abs(circle.Center.Y - top);
float distToBottom = Math.Abs(circle.Center.Y - bottom);
float distToLeft = Math.Abs(circle.Center.X - left);
float distToRight = Math.Abs(circle.Center.X - right);
// Choose the closest distance to the collision boundary as the pushing direction
Vector2 pushAmount = new Vector2(); // How much should be pushed relative to circle
float min = Math.Min(Math.Min(Math.Min(distToTop, distToBottom), distToLeft), distToRight);
pushAmount.Y += min == distToTop ? distToTop + OFFSET : 0;
pushAmount.Y += min == distToBottom ? -distToBottom - OFFSET : 0;
pushAmount.X += min == distToLeft ? -distToLeft - OFFSET : 0;
pushAmount.X += min == distToRight ? distToRight + OFFSET : 0;
// Only move the non-static object
if (rect.IsStatic)
{
circle.Center += pushAmount;
}
else if (circle.IsStatic)
{
rect.Center -= pushAmount;
}
else
{
circle.Center += pushAmount / 2;
rect.Center -= pushAmount / 2;
}
}
}
