public bool RayCastToCollider(Ray ray, out Hit hit, Collider collider)
{
hit = new Hit(0, null);
Collider rect = collider;
Vector2 relative = rect.GetCentrePoint() - ray.position;
Matrix3 t = collider.GetConnectedPhysicsObject().GetGlobalTransform();
float minTotalDistance = 0;
float maxTotalDistance = float.PositiveInfinity;
float scale = t.GetScaleX();
Vector2 max = rect.GetLocalHalfWidthHeightVector() * scale;
Vector2 min = max * -1;
Vector2 x = new Vector2(t.m11, t.m21) / scale;
float e = Vector2.Dot(x, relative);
float f = Vector2.Dot(x, ray.direction);
float minimumDistance;
float maximumDistance;
if (Math.Abs(f) > 0.0001f)
{
f = 1 / f;
minimumDistance = (e + min.x) * f;
maximumDistance = (e + max.x) * f;
if (minimumDistance > maximumDistance)
{
float cache = minimumDistance;
minimumDistance = maximumDistance;
maximumDistance = cache;
}
maxTotalDistance = maximumDistance;
if (minimumDistance > 0)
{
minTotalDistance = minimumDistance;
}
if (maxTotalDistance < minTotalDistance)
{
return(false);
}
}
else if (min.x - e > 0 || max.x - e < 0)
{
return(false);
}
Vector2 y = new Vector2(t.m12, t.m22) / scale;
e = Vector2.Dot(y, relative);
f = Vector2.Dot(y, ray.direction);
if (Math.Abs(f) > 0.0001f)
{
f = 1 / f;
minimumDistance = (e + min.y) * f;
maximumDistance = (e + max.y) * f;
if (minimumDistance > maximumDistance)
{
float cache = minimumDistance;
minimumDistance = maximumDistance;
maximumDistance = cache;
}
if (maximumDistance < maxTotalDistance)
{
maxTotalDistance = maximumDistance;
}
if (minimumDistance > minTotalDistance)
{
minTotalDistance = minimumDistance;
}
if (maxTotalDistance < minTotalDistance)
{
return(false);
}
}
else if (min.y - e > 0 || max.y - e < 0)
{
return(false);
}
hit = new Hit(minTotalDistance, collider.GetConnectedPhysicsObject());
return(true);
}
public bool RayCast(Ray ray, out Hit hit, float magnitude = float.PositiveInfinity, params CollisionLayer[] ignoredLayers)
{
//this raycast was done using this algorithm
//http://www.opengl-tutorial.org/miscellaneous/clicking-on-objects/picking-with-custom-ray-obb-function/
//this page isn't the only one to use these concepts but it is where I found out how to do this without (many) transformation shenanigans
bool collided = false;
float distance = float.PositiveInfinity;
PhysicsObject colliderHit = null;
for (int i = 0; i < objList.Count; i++)
{
Collider rect = objList[i].GetCollider();
if (ignoredLayers.Contains(rect.GetLayer()) || (ray.position - rect.GetCentrePoint()).MagnitudeSquared() > magnitude * magnitude)
{
continue;
}
Vector2 relative = rect.GetCentrePoint() - ray.position;
Matrix3 t = objList[i].GetGlobalTransform();
float minTotalDistance = 0;
float maxTotalDistance = float.PositiveInfinity;
//everything in the game has uniform scaling on x and y (because otherwise there are rotation issues) so only one getscale is required
float scale = t.GetScaleX();
Vector2 max = rect.GetLocalHalfWidthHeightVector() * scale;
Vector2 min = max * -1;
//X axis
//We don't use t.GetRightVector() to cut down on the square rooting
Vector2 x = new Vector2(t.m11, t.m21) / scale;
//the distance between the ray and the centre of the rectangle along the rectangle's x axis
float e = Vector2.Dot(x, relative);
//The projection of the ray's direction onto the rectangle's x axis
float f = Vector2.Dot(x, ray.direction);
float minimumDistance;
float maximumDistance;
//if f is around zero that means f is almost the same as x: aka it is parallel and is not colliding (unless you have a really massive object)
if (Math.Abs(f) > 0.0001f)
{
f = 1 / f;
//these contain the distance between the ray position and the hit point
//there are two because we are crossing two lines for each axis
//e is translation, f is rotation
minimumDistance = (e + min.x) * f;
maximumDistance = (e + max.x) * f;
if (minimumDistance > maximumDistance)
{
float cache = minimumDistance;
minimumDistance = maximumDistance;
maximumDistance = cache;
}
maxTotalDistance = maximumDistance;
//min distance should be more than zero. If it isn't, it should be ignored
if (minimumDistance > 0)
{
minTotalDistance = minimumDistance;
}
}
else if (min.x - e > 0 || max.x - e < 0)
{
continue;
}
//Y axis (same as x basically)
Vector2 y = new Vector2(t.m12, t.m22) / scale;
e = Vector2.Dot(y, relative);
f = Vector2.Dot(y, ray.direction);
if (Math.Abs(f) > 0.0001f)
{
f = 1 / f;
minimumDistance = (e + min.y) * f;
maximumDistance = (e + max.y) * f;
if (minimumDistance > maximumDistance)
{
float cache = minimumDistance;
minimumDistance = maximumDistance;
maximumDistance = cache;
}
if (maximumDistance < maxTotalDistance)
{
maxTotalDistance = maximumDistance;
}
if (minimumDistance > minTotalDistance)
{
minTotalDistance = minimumDistance;
}
if (maxTotalDistance < minTotalDistance)
{
continue;
}
}
else if (min.y - e > 0 || max.y - e < 0)
{
continue;
}
collided = true;
if (minTotalDistance < distance)
{
distance = minTotalDistance;
colliderHit = objList[i];
}
}
hit = new Hit(distance, colliderHit);
if (collided)
{
return(true);
}
return(false);
}
