bool MFCollision_PlaneTriTest(const MFVector& plane, const MFVector& p0, const MFVector& p1, const MFVector& p2, MFVector *pIntersectionPoint)
{
float t0 = p0.DotH(plane);
float t1 = p1.DotH(plane);
float t2 = p2.DotH(plane);
if(t0 <= 0.0f && t1 <= 0.0f && t2 <= 0)
return false;
if(t0 >= 0.0f && t1 >= 0.0f && t2 >= 0)
return false;
if(pIntersectionPoint)
{
// TODO: calculate point
}
return true;
}
bool MFCollision_SpherePlaneTest(const MFVector& spherePos, float radius, const MFVector& plane, MFCollisionResult *pResult)
{
if(!pResult)
{
return spherePos.DotH(plane) < radius;
}
else
{
float d = spherePos.DotH(plane);
pResult->bCollide = d < radius;
if(pResult->bCollide)
{
pResult->depth = radius - d;
pResult->normal = plane;
pResult->intersectionPoint.Mad3(pResult->normal, -(d + pResult->depth*0.5f), spherePos);
}
return pResult->bCollide;
}
}
bool MFCollision_RaySlabTest(const MFVector& rayPos, const MFVector& rayDir, const MFVector& plane, float slabHalfWidth, MFRayIntersectionResult *pResult)
{
float a = plane.Dot3(rayDir);
// if ray is parallel to plane
if(a > -MFALMOST_ZERO && a < MFALMOST_ZERO)
{
// TODO: this is intentionally BROKEN
// this is a near impossible case, and it adds a lot of junk to the function
/*
if(MFAbs(rayPos.DotH(plane)) <= slabHalfWidth)
{
if(pResult)
{
pResult->time = 0.0f;
}
return true;
}
*/
return false;
}
// otherwise we can do the conventional test
float inva = MFRcp(a);
float t = -rayPos.DotH(plane);
float t1 = (t + slabHalfWidth) * inva;
float t2 = (t - slabHalfWidth) * inva;
t = MFMin(t1, t2);
t2 = MFMax(t1, t2);
if(t > 1.0f || t2 < 0.0f)
return false;
if(pResult)
{
pResult->time = MFMax(t, 0.0f);
pResult->surfaceNormal = a > 0.0f ? -plane : plane;
}
return true;
}
bool MFCollision_SweepSphereTriTest(const MFVector &sweepSpherePos, const MFVector &sweepSphereVelocity, float sweepSphereRadius, const MFCollisionTriangle &tri, MFSweepSphereResult *pResult)
{
MFRayIntersectionResult result;
// test the triangle surface
if(!MFCollision_RaySlabTest(sweepSpherePos, sweepSphereVelocity, tri.plane, sweepSphereRadius, &result))
return false;
MFVector intersection = sweepSpherePos + sweepSphereVelocity * result.time;
// test if intersection is inside the triangle
float dot0, dot1, dot2;
dot0 = intersection.DotH(tri.edgePlanes[0]);
// if(dot0 > sphereRadius)
// return false;
dot1 = intersection.DotH(tri.edgePlanes[1]);
// if(dot1 > sphereRadius)
// return false;
dot2 = intersection.DotH(tri.edgePlanes[2]);
// if(dot2 > sphereRadius)
// return false;
// test if intersection is inside the triangle face
if(dot0 >= 0.0f && dot1 >= 0.0f && dot2 >= 0.0f)
goto collision;
// test the 3 edges
if(dot0 < 0.0f)
{
if(MFCollision_RayCapsuleTest(sweepSpherePos, sweepSphereVelocity, tri.verts[0], tri.verts[1]-tri.verts[0], sweepSphereRadius, &result))
goto collision;
}
if(dot1 < 0.0f)
{
if(MFCollision_RayCapsuleTest(sweepSpherePos, sweepSphereVelocity, tri.verts[1], tri.verts[2]-tri.verts[1], sweepSphereRadius, &result))
goto collision;
}
if(dot2 < 0.0f)
{
if(MFCollision_RayCapsuleTest(sweepSpherePos, sweepSphereVelocity, tri.verts[2], tri.verts[0]-tri.verts[2], sweepSphereRadius, &result))
goto collision;
}
return false;
collision:
if(result.time == 0.0f)
{
// this is for double sided collision.
float dot = sweepSpherePos.DotH(tri.plane);
float amountResolve = sweepSphereRadius - MFAbs(dot);
pResult->intersectionReaction = result.surfaceNormal * amountResolve;
}
else
pResult->intersectionReaction = MFVector::zero;
pResult->surfaceNormal = result.surfaceNormal;
pResult->time = result.time;
return true;
}
