bool TestForOverlap( const BoxCollider* a,
const BoxCollider* b,
const EnVector3& axis)
{
float aProjection = ProjectToAxis(a, axis);
float bProjection = ProjectToAxis(b, axis);
EnVector3 abVector = b->parent->GetLocalAxis(3) - a->parent->GetLocalAxis(3);
float abVectorProjection = abs(abVector.ADot(axis));
return abVectorProjection <= (aProjection + bProjection);
}
/// [groupSyntax]
bool Triangle::Intersects(const AABB &aabb) const
{
/** The AABB-Triangle test implementation is based on the pseudo-code in
Christer Ericson's Real-Time Collision Detection, pp. 169-172. */
///@todo The Triangle-AABB intersection test can be greatly optimized by manually unrolling loops, trivial math and by avoiding
/// unnecessary copying.
float t1, t2, a1, a2;
const float3 e[3] = { float3(1,0,0), float3(0,1,0), float3(0,0,1) };
for(int i = 0; i < 3; ++i)
{
ProjectToAxis(e[i], t1, t2);
aabb.ProjectToAxis(e[i], a1, a2);
if (!RangesOverlap(t1, t2, a1, a2))
return false;
}
float3 n = UnnormalizedNormalCCW();
ProjectToAxis(n, t1, t2);
aabb.ProjectToAxis(n, a1, a2);
if (!RangesOverlap(t1, t2, a1, a2))
return false;
const float3 t[3] = { b-a, c-a, c-b };
for(int i = 0; i < 3; ++i)
for(int j = 0; j < 3; ++j)
{
float3 axis = Cross(e[i], t[j]);
float len = axis.LengthSq();
if (len <= 1e-4f)
continue; // Ignore tests on degenerate axes.
ProjectToAxis(axis, t1, t2);
aabb.ProjectToAxis(axis, a1, a2);
if (!RangesOverlap(t1, t2, a1, a2))
return false;
}
// No separating axis exists, the AABB and triangle intersect.
return true;
}
