// Sphere Plane Collision - returns true if collsion exists - takes Point3d params
bool Collision::SpherePlane(Vector3d& centerSphere, float radiusSphere,
Vector3d planeNormal, Point3d p1, Point3d p2, Point3d p3, Point3d p4){
float dist1 = 0.0;
float dist2 = 0.0;
// this checks for the collsion on both sides of the plane
if(RayPlane(planeNormal.getX(), planeNormal.getY(), planeNormal.getZ(), p1.getX(), p1.getY(), p1.getZ(),
centerSphere.getX(), centerSphere.getY(), centerSphere.getZ(), -planeNormal.getX(), -planeNormal.getY(), -planeNormal.getZ(),
p1, p2, p3, p4, &dist1) || RayPlane(-planeNormal.getX(), -planeNormal.getY(), -planeNormal.getZ(), p1.getX(), p1.getY(), p1.getZ(),
centerSphere.getX(), centerSphere.getY(), centerSphere.getZ(), planeNormal.getX(), planeNormal.getY(), planeNormal.getZ(),
p1, p2, p3, p4, &dist2)){
if(dist1 > radiusSphere || dist2 > radiusSphere){ // if either distance is > the radiusSphere....no collision
return false;
}
// indicates that we are on the side where dist1 has been determined to be > 0
// the else is the other side of the plane. This calculates the point as well
// as the new location of the sphere
if(dist1 > 0 ){
centerSphere.setX(centerSphere.getX() + planeNormal.getX() * (radiusSphere - dist1));
centerSphere.setY(centerSphere.getY() + planeNormal.getY() * (radiusSphere - dist1));
centerSphere.setZ(centerSphere.getZ() + planeNormal.getZ() * (radiusSphere - dist1));
}else{
centerSphere.setX(centerSphere.getX() + planeNormal.getX() * (radiusSphere - dist2));
centerSphere.setY(centerSphere.getY() + planeNormal.getY() * (radiusSphere - dist2));
centerSphere.setZ(centerSphere.getZ() + planeNormal.getZ() * (radiusSphere - dist2));
}
return true;
}
return false;
}
bool RayTriangle(const Vector3& rayStart, const Vector3& rayDir,
const Vector3& triP0, const Vector3& triP1, const Vector3& triP2,
float& t, float triExpansionEpsilon)
{
++Application::mStatistics.mRayTriangleTests;
Math::Vector3 normal = (triP1 - triP0).Cross(triP2 - triP0).Normalized();
if(RayPlane(rayStart, rayDir, Math::Vector4(normal.x, normal.y, normal.z, normal.Dot(triP0)), t))
{
Math::Vector3 pointOnPlane = (rayDir * t) + rayStart;
Math::Vector3 barycentric;
return BarycentricCoordinates(pointOnPlane, triP0, triP1, triP2, barycentric.x, barycentric.y, barycentric.z, triExpansionEpsilon);
}
return false;
}
bool RayAabb(const Vector3& rayStart, const Vector3& rayDir,
const Vector3& aabbMin, const Vector3& aabbMax, float& t)
{
++Application::mStatistics.mRayAabbTests;
if(PointAabb(rayStart, aabbMin, aabbMax))
{
t = 0.0f;
return true;
}
std::vector<float> tVals;
std::vector<Plane> planes;
if(rayDir.x)
{
planes.emplace_back(Plane(Math::Vector3(aabbMin.x / Math::Abs(aabbMin.x), 0.0f, 0.0f), aabbMin));
planes.emplace_back(Plane(Math::Vector3(aabbMax.x / Math::Abs(aabbMax.x), 0.0f, 0.0f), aabbMax));
tVals.emplace_back(FLT_MAX);
tVals.emplace_back(FLT_MAX);
}
else
{
if(Math::Clamp(rayStart.x, aabbMin.x, aabbMax.x) != rayStart.x)
{
return false;
}
}
if(rayDir.y)
{
planes.emplace_back(Plane(Math::Vector3(0.0f, aabbMin.y / Math::Abs(aabbMin.y), 0.0f), aabbMin));
planes.emplace_back(Plane(Math::Vector3(0.0f, aabbMax.y / Math::Abs(aabbMax.y), 0.0f), aabbMax));
tVals.emplace_back(FLT_MAX);
tVals.emplace_back(FLT_MAX);
}
else
{
if(Math::Clamp(rayStart.y, aabbMin.y, aabbMax.y) != rayStart.y)
{
return false;
}
}
if(rayDir.z)
{
planes.emplace_back(Plane(Math::Vector3(0.0f, 0.0f, aabbMin.z / Math::Abs(aabbMin.z)), aabbMin));
planes.emplace_back(Plane(Math::Vector3(0.0f, 0.0f, aabbMax.z / Math::Abs(aabbMax.z)), aabbMax));
tVals.emplace_back(FLT_MAX);
tVals.emplace_back(FLT_MAX);
}
else
{
if(Math::Clamp(rayStart.z, aabbMin.z, aabbMax.z) != rayStart.z)
{
return false;
}
}
for(int i = 0; i < planes.size(); i += 2)
{
RayPlane(rayStart, rayDir, planes[i].mData, tVals[i]);
RayPlane(rayStart, rayDir, planes[i + 1].mData, tVals[i + 1]);
//we dot with positive plane axis to get the desired component
if(rayDir.Dot(Math::Vector3(planes[i + 1].mData.x, planes[i + 1].mData.y, planes[i + 1].mData.z)) < 0.0f)
{
std::swap(tVals[i], tVals[i + 1]);
}
}
float tmin = -FLT_MAX;
float tmax = FLT_MAX;
for(int i = 0; i < tVals.size(); i += 2)
{
tmin = Math::Max(tmin, tVals[i]);
tmax = Math::Min(tmax, tVals[i + 1]);
}
//tmin should be start of our collision
if(tmin < tmax)
{
if(tmin > 0.0f)
{
t = tmin;
return true;
}
}
return false;
}
