public override IEnumerable IntersectionIterator(Ray ray)
{
double radiusSquared = radius * radius;
Vector2 rayOrigin = new Vector2(ray.origin);
Vector2 rayDirectionXY = new Vector2(ray.direction);
Vector2 rayDirection = rayDirectionXY.GetNormal();
Vector2 thisPosition = Vector2.Zero;
Vector2 deltaFromShpereCenterToRayOrigin = rayOrigin - thisPosition;
double distanceFromCircleCenterToRayOrigin = Vector2.Dot(deltaFromShpereCenterToRayOrigin, rayDirection);
double lengthFromRayOrginToCircleCenterSquared = Vector2.Dot(deltaFromShpereCenterToRayOrigin, deltaFromShpereCenterToRayOrigin);
double lengthFromRayOrigintoNearEdgeOfCircleSquared = lengthFromRayOrginToCircleCenterSquared - radiusSquared;
double distanceFromCircleCenterToRaySquared = distanceFromCircleCenterToRayOrigin * distanceFromCircleCenterToRayOrigin;
double amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared = distanceFromCircleCenterToRaySquared - lengthFromRayOrigintoNearEdgeOfCircleSquared;
if (amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared > 0)
{
double distanceFromRayOriginToCircleCenter = -distanceFromCircleCenterToRayOrigin;
double amountCircleCenterToRayIsGreaterThanRayOriginToEdge = Math.Sqrt(amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared);
double scaleRatio = ray.direction.Length / rayDirectionXY.Length;
if ((ray.intersectionType & IntersectionType.FrontFace) == IntersectionType.FrontFace)
{
IntersectInfo info = new IntersectInfo();
info.hitType = IntersectionType.FrontFace;
info.closestHitObject = this;
double distanceToFrontHit = (distanceFromRayOriginToCircleCenter - amountCircleCenterToRayIsGreaterThanRayOriginToEdge) * scaleRatio;
info.distanceToHit = distanceToFrontHit;
info.hitPosition = ray.origin + ray.direction * info.distanceToHit;
if (info.hitPosition.z > -height / 2 && info.hitPosition.z < height / 2)
{
info.normalAtHit = new Vector3(info.hitPosition.x, info.hitPosition.y, 0).GetNormal();
yield return info;
}
}
if ((ray.intersectionType & IntersectionType.BackFace) == IntersectionType.BackFace)
{
IntersectInfo info = new IntersectInfo();
info.hitType = IntersectionType.BackFace;
info.closestHitObject = this;
double distanceToBackHit = (distanceFromRayOriginToCircleCenter + amountCircleCenterToRayIsGreaterThanRayOriginToEdge) * scaleRatio;
info.distanceToHit = distanceToBackHit;
info.hitPosition = ray.origin + ray.direction * info.distanceToHit;
if (info.hitPosition.z > -height / 2 && info.hitPosition.z < height / 2)
{
info.normalAtHit = -(new Vector3(info.hitPosition.x, info.hitPosition.y, 0).GetNormal());
yield return info;
}
}
{
bool inFrontOfTopFace;
double testDistanceToHit = topPlane.GetDistanceToIntersection(ray, out inFrontOfTopFace);
Vector3 topHitPosition = ray.origin + ray.direction * testDistanceToHit;
if (topHitPosition.x * topHitPosition.x + topHitPosition.y * topHitPosition.y < topRadius * topRadius)
{
if ((ray.intersectionType & IntersectionType.FrontFace) == IntersectionType.FrontFace && inFrontOfTopFace)
{
IntersectInfo topHitInfo = new IntersectInfo();
topHitInfo.hitPosition = topHitPosition;
topHitInfo.closestHitObject = this;
topHitInfo.hitType = IntersectionType.FrontFace;
topHitInfo.normalAtHit = topPlane.planeNormal;
topHitInfo.distanceToHit = testDistanceToHit;
yield return topHitInfo;
}
if ((ray.intersectionType & IntersectionType.BackFace) == IntersectionType.BackFace && !inFrontOfTopFace)
{
IntersectInfo topHitInfo = new IntersectInfo();
topHitInfo.hitPosition = topHitPosition;
topHitInfo.closestHitObject = this;
topHitInfo.hitType = IntersectionType.BackFace;
topHitInfo.normalAtHit = -topPlane.planeNormal;
topHitInfo.distanceToHit = testDistanceToHit;
yield return topHitInfo;
}
}
}
{
bool inFrontOfBottomFace;
double testDistanceToHit = bottomPlane.GetDistanceToIntersection(ray, out inFrontOfBottomFace);
Vector3 bottomHitPosition = ray.origin + ray.direction * testDistanceToHit;
if (bottomHitPosition.x * bottomHitPosition.x + bottomHitPosition.y * bottomHitPosition.y < radius * radius)
{
if ((ray.intersectionType & IntersectionType.FrontFace) == IntersectionType.FrontFace && inFrontOfBottomFace)
{
IntersectInfo bottomHitInfo = new IntersectInfo();
bottomHitInfo.hitPosition = bottomHitPosition;
bottomHitInfo.closestHitObject = this;
bottomHitInfo.hitType = IntersectionType.FrontFace;
bottomHitInfo.normalAtHit = bottomPlane.planeNormal;
bottomHitInfo.distanceToHit = testDistanceToHit;
yield return bottomHitInfo;
}
if ((ray.intersectionType & IntersectionType.BackFace) == IntersectionType.BackFace && !inFrontOfBottomFace)
{
IntersectInfo bottomHitInfo = new IntersectInfo();
bottomHitInfo.hitPosition = bottomHitPosition;
bottomHitInfo.closestHitObject = this;
bottomHitInfo.hitType = IntersectionType.BackFace;
bottomHitInfo.normalAtHit = -bottomPlane.planeNormal;
bottomHitInfo.distanceToHit = testDistanceToHit;
yield return bottomHitInfo;
}
}
}
}
}
public override IntersectInfo GetClosestIntersection(Ray ray)
{
double radiusSquared = radius * radius;
Vector2 rayOrigin = new Vector2(ray.origin);
Vector2 rayDirectionXY = new Vector2(ray.direction);
Vector2 rayDirection = rayDirectionXY.GetNormal();
Vector2 thisPosition = Vector2.Zero;
Vector2 deltaFromShpereCenterToRayOrigin = rayOrigin - thisPosition;
double distanceFromCircleCenterToRayOrigin = Vector2.Dot(deltaFromShpereCenterToRayOrigin, rayDirection); // negative means the Circle is in front of the ray.
double lengthFromRayOrginToCircleCenterSquared = Vector2.Dot(deltaFromShpereCenterToRayOrigin, deltaFromShpereCenterToRayOrigin);
double lengthFromRayOrigintoNearEdgeOfCircleSquared = lengthFromRayOrginToCircleCenterSquared - radiusSquared;
double distanceFromCircleCenterToRaySquared = distanceFromCircleCenterToRayOrigin * distanceFromCircleCenterToRayOrigin;
double amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared = distanceFromCircleCenterToRaySquared - lengthFromRayOrigintoNearEdgeOfCircleSquared;
if (amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared > 0)
{
{
bool inFrontOfTop;
double testDistanceToHit = topPlane.GetDistanceToIntersection(ray, out inFrontOfTop);
bool wantFrontAndInFront = (ray.intersectionType & IntersectionType.FrontFace) == IntersectionType.FrontFace && inFrontOfTop;
bool wantBackAndInBack = (ray.intersectionType & IntersectionType.BackFace) == IntersectionType.BackFace && !inFrontOfTop;
if (wantFrontAndInFront || wantBackAndInBack)
{
Vector3 topHitPosition = ray.origin + ray.direction * testDistanceToHit;
if (topHitPosition.x * topHitPosition.x + topHitPosition.y * topHitPosition.y < topRadius * topRadius)
{
IntersectInfo topHitInfo = new IntersectInfo();
topHitInfo.hitPosition = topHitPosition;
topHitInfo.closestHitObject = this;
if (ray.intersectionType == IntersectionType.FrontFace)
{
topHitInfo.hitType = IntersectionType.FrontFace;
topHitInfo.normalAtHit = topPlane.planeNormal;
}
else
{
topHitInfo.hitType = IntersectionType.BackFace;
topHitInfo.normalAtHit = -topPlane.planeNormal;
}
topHitInfo.distanceToHit = testDistanceToHit;
return topHitInfo;
}
}
}
{
bool inFrontOfBottom;
double testDistanceToHit = bottomPlane.GetDistanceToIntersection(ray, out inFrontOfBottom);
if (ray.intersectionType == IntersectionType.FrontFace && inFrontOfBottom
|| ray.intersectionType == IntersectionType.BackFace && !inFrontOfBottom)
{
Vector3 bottomHitPosition = ray.origin + ray.direction * testDistanceToHit;
if (bottomHitPosition.x * bottomHitPosition.x + bottomHitPosition.y * bottomHitPosition.y < radius * radius)
{
IntersectInfo bottomHitInfo = new IntersectInfo();
bottomHitInfo.hitPosition = bottomHitPosition;
bottomHitInfo.closestHitObject = this;
if (ray.intersectionType == IntersectionType.FrontFace)
{
bottomHitInfo.hitType = IntersectionType.FrontFace;
bottomHitInfo.normalAtHit = bottomPlane.planeNormal;
}
else
{
bottomHitInfo.hitType = IntersectionType.BackFace;
bottomHitInfo.normalAtHit = -bottomPlane.planeNormal;
}
bottomHitInfo.distanceToHit = testDistanceToHit;
return bottomHitInfo;
}
}
}
IntersectInfo info = new IntersectInfo();
info.closestHitObject = this;
info.hitType = IntersectionType.FrontFace;
if (ray.isShadowRay)
{
return info;
}
double distanceFromRayOriginToCircleCenter = -distanceFromCircleCenterToRayOrigin;
double amountCircleCenterToRayIsGreaterThanRayOriginToEdge = Math.Sqrt(amountCircleCenterToRayIsGreaterThanRayOriginToEdgeSquared);
double scaleRatio = ray.direction.Length / rayDirectionXY.Length;
if (ray.intersectionType == IntersectionType.FrontFace)
{
double distanceToFrontHit = (distanceFromRayOriginToCircleCenter - amountCircleCenterToRayIsGreaterThanRayOriginToEdge) * scaleRatio;
if (distanceToFrontHit > ray.maxDistanceToConsider || distanceToFrontHit < ray.minDistanceToConsider)
{
return null;
}
info.distanceToHit = distanceToFrontHit;
info.hitPosition = ray.origin + ray.direction * info.distanceToHit;
if (info.hitPosition.z < -height / 2 || info.hitPosition.z > height / 2)
{
return null;
}
info.normalAtHit = new Vector3(info.hitPosition.x, info.hitPosition.y, 0).GetNormal();
}
else if (ray.intersectionType == IntersectionType.BackFace)// check back faces
{
double distanceToBackHit = (distanceFromRayOriginToCircleCenter + amountCircleCenterToRayIsGreaterThanRayOriginToEdge) * scaleRatio;
if (distanceToBackHit > ray.maxDistanceToConsider || distanceToBackHit < ray.minDistanceToConsider)
{
return null;
}
info.hitType = IntersectionType.BackFace;
info.distanceToHit = distanceToBackHit;
info.hitPosition = ray.origin + ray.direction * info.distanceToHit;
if (info.hitPosition.z < height / 2 || info.hitPosition.z > height / 2)
{
return null;
}
info.normalAtHit = -(new Vector3(info.hitPosition.x, info.hitPosition.y, 0).GetNormal());
}
return info;
}
return null;
}
