• Advertisement
Sign in to follow this  

Sphere to Plane Collision - Getting opposite direction

This topic is 1674 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

// Structs
struct Sphere
    Vector3 center;
    float radius;
struct Plane
    Vector3 normal;
    float offset;
// Collision Check
bool SphereToPlane( Vector3 &PointToSphere,Sphere &sphere,Plane &plane )
    // Calculates the distance from the sphere center to the plane
    float dist = DotProduct(plane.normal,sphere.center) - plane.offset;
    // Save out the vector between the sphere and plane
    PointToSphere = plane.normal*dist;
    // Check to see if the sphere is straddling the plane
    if(dist < -sphere.radius || dist > sphere.radius)
        return false;
    return true;
// Reacting to the collision
bool SphereToPlaneReaction( Sphere &sphere,Plane &plane )
    Vector3 toPoint;
    // Check if there was a collision
    if( !SphereToPlane(toPoint,sphere,plane) )
        return false;
    // See how far they penetrated each other
    float fLength = toPoint.length();
    float penetrationDist = sphere.radius - fLength;
    toPoint /= fLength; // Normalize
    // Set it's position back so it's not colliding anymore
    sphere.center += toPoint * penetrationDist;
    return true;

Ok when i collide against a plane the direction that it moves the sphere back to is basically the reflection of what it is actually supposed to be.


if the plane is flat on the ground it works perfectly but as soon as it has rotation, the it gets put in the opposite direction that it's supposed to.


I tried reflecting the final position across the normal but that didnt work. any ideas?







EDIT: I fixed it, I was calculating the normal wrong for the plane

Edited by Muzzy A

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement