public static void Solve3d(float3 up, SurfaceConstraintInfo constraint0, SurfaceConstraintInfo constraint1, SurfaceConstraintInfo constraint2, ref float3 velocity)
{
float3 plane0 = constraint0.Plane.Normal;
float3 plane1 = constraint1.Plane.Normal;
float3 plane2 = constraint2.Plane.Normal;
float4x4 m = new float4x4();
float3 r0 = math.cross(plane1, plane2);
float3 r1 = math.cross(plane2, plane0);
float3 r2 = math.cross(plane0, plane1);
m.c0 = new float4(r0, sfloat.Zero);
m.c1 = new float4(r1, sfloat.Zero);
m.c2 = new float4(r2, sfloat.Zero);
m.c3 = new float4(sfloat.Zero, sfloat.Zero, sfloat.Zero, sfloat.One);
sfloat det = math.dot(r0, plane0);
sfloat tst = math.abs(det);
if (tst < k_Epsilon)
{
Sort3d(ref constraint0, ref constraint1, ref constraint2);
Solve2d(up, constraint1, constraint2, ref velocity);
Solve2d(up, constraint0, constraint2, ref velocity);
Solve2d(up, constraint0, constraint1, ref velocity);
return;
}
float3 t = new float3(
math.dot(plane0, constraint0.Velocity),
math.dot(plane1, constraint1.Velocity),
math.dot(plane2, constraint2.Velocity));
float3 pointVel = math.rotate(m, t);
pointVel /= det;
velocity = pointVel;
}
public static void Sort3d(ref SurfaceConstraintInfo plane0, ref SurfaceConstraintInfo plane1, ref SurfaceConstraintInfo plane2)
{
int priority0 = plane0.Priority;
int priority1 = plane1.Priority;
int priority2 = plane2.Priority;
if (priority0 <= priority1)
{
if (priority1 <= priority2)
{
// 0, 1, 2
}
else if (priority0 <= priority2)
{
// 0, 2, 1
SwapPlanes(ref plane1, ref plane2);
}
else
{
// 1, 2, 0
SwapPlanes(ref plane0, ref plane1);
SwapPlanes(ref plane0, ref plane2);
}
}
else
{
if (priority2 < priority1)
{
// 2, 1, 0
SwapPlanes(ref plane0, ref plane2);
}
else if (priority2 > priority0)
{
// 1, 0, 2
SwapPlanes(ref plane0, ref plane1);
}
else
{
// 2, 0, 1
SwapPlanes(ref plane0, ref plane1);
SwapPlanes(ref plane1, ref plane2);
}
}
}
public static unsafe void Solve(
sfloat deltaTime, sfloat minDeltaTime, float3 up, sfloat maxVelocity,
NativeList <SurfaceConstraintInfo> constraints, ref float3 position, ref float3 velocity, out sfloat integratedTime, bool useConstraintVelocities = true
)
{
// List of planes to solve against (up to 4)
SurfaceConstraintInfo *supportPlanes = stackalloc SurfaceConstraintInfo[4];
int numSupportPlanes = 0;
sfloat remainingTime = deltaTime;
sfloat currentTime = sfloat.Zero;
// Clamp the input velocity to max movement speed
ClampToMaxLength(maxVelocity, ref velocity);
while (remainingTime > sfloat.Zero)
{
int hitIndex = -1;
sfloat minCollisionTime = remainingTime;
// Iterate over constraints and solve them
for (int i = 0; i < constraints.Length; i++)
{
if (constraints[i].Touched)
{
continue;
}
SurfaceConstraintInfo constraint = constraints[i];
float3 relVel = velocity - (useConstraintVelocities ? constraint.Velocity : float3.zero);
sfloat relProjVel = -math.dot(relVel, constraint.Plane.Normal);
if (relProjVel < k_Epsilon)
{
continue;
}
// Clamp distance to 0, since penetration is handled by constraint.Velocity already
sfloat distance = math.max(constraint.Plane.Distance, sfloat.Zero);
if (distance < minCollisionTime * relProjVel)
{
minCollisionTime = distance / relProjVel;
hitIndex = i;
}
}
// Integrate
{
currentTime += minCollisionTime;
remainingTime -= minCollisionTime;
position += minCollisionTime * velocity;
}
if (hitIndex < 0 || currentTime > minDeltaTime)
{
break;
}
// Mark constraint as touched
{
var constraint = constraints[hitIndex];
constraint.Touched = true;
constraints[hitIndex] = constraint;
}
// Add the hit to the current list of active planes
supportPlanes[numSupportPlanes] = constraints[hitIndex];
if (!useConstraintVelocities)
{
supportPlanes[numSupportPlanes].Velocity = float3.zero;
}
numSupportPlanes++;
// Solve support planes
ExamineActivePlanes(up, supportPlanes, ref numSupportPlanes, ref velocity);
// Clamp the solved velocity to max movement speed
ClampToMaxLength(maxVelocity, ref velocity);
// Can't handle more than 4 support planes
if (numSupportPlanes == 4)
{
break;
}
}
integratedTime = currentTime;
}
public static unsafe void ExamineActivePlanes(float3 up, SurfaceConstraintInfo *supportPlanes, ref int numSupportPlanes, ref float3 velocity)
{
switch (numSupportPlanes)
{
case 1:
{
Solve1d(supportPlanes[0], ref velocity);
return;
}
case 2:
{
// Test whether we need plane 0 at all
float3 tempVelocity = velocity;
Solve1d(supportPlanes[1], ref tempVelocity);
bool plane0Used = Test1d(supportPlanes[0], tempVelocity);
if (!plane0Used)
{
// Compact the buffer and reduce size
supportPlanes[0] = supportPlanes[1];
numSupportPlanes = 1;
// Write back the result
velocity = tempVelocity;
}
else
{
Solve2d(up, supportPlanes[0], supportPlanes[1], ref velocity);
}
return;
}
case 3:
{
// Try to drop both planes
float3 tempVelocity = velocity;
Solve1d(supportPlanes[2], ref tempVelocity);
bool plane0Used = Test1d(supportPlanes[0], tempVelocity);
if (!plane0Used)
{
bool plane1Used = Test1d(supportPlanes[1], tempVelocity);
if (!plane1Used)
{
// Compact the buffer and reduce size
supportPlanes[0] = supportPlanes[2];
numSupportPlanes = 1;
goto case 1;
}
}
// Try to drop plane 0 or 1
for (int testPlane = 0; testPlane < 2; testPlane++)
{
tempVelocity = velocity;
Solve2d(up, supportPlanes[testPlane], supportPlanes[2], ref tempVelocity);
bool planeUsed = Test1d(supportPlanes[1 - testPlane], tempVelocity);
if (!planeUsed)
{
supportPlanes[0] = supportPlanes[testPlane];
supportPlanes[1] = supportPlanes[2];
numSupportPlanes--;
goto case 2;
}
}
// Try solve all three
Solve3d(up, supportPlanes[0], supportPlanes[1], supportPlanes[2], ref velocity);
return;
}
case 4:
{
for (int i = 0; i < 3; i++)
{
float3 tempVelocity = velocity;
Solve3d(up, supportPlanes[(i + 1) % 3], supportPlanes[(i + 2) % 3], supportPlanes[3], ref tempVelocity);
bool planeUsed = Test1d(supportPlanes[i], tempVelocity);
if (!planeUsed)
{
supportPlanes[i] = supportPlanes[2];
supportPlanes[2] = supportPlanes[3];
numSupportPlanes = 3;
goto case 3;
}
}
// Nothing can be dropped so we've failed to solve,
// now we do all 3d combinations
float3 tempVel = velocity;
SurfaceConstraintInfo sp0 = supportPlanes[0];
SurfaceConstraintInfo sp1 = supportPlanes[1];
SurfaceConstraintInfo sp2 = supportPlanes[2];
SurfaceConstraintInfo sp3 = supportPlanes[3];
Solve3d(up, sp0, sp1, sp2, ref tempVel);
Solve3d(up, sp0, sp1, sp3, ref tempVel);
Solve3d(up, sp0, sp2, sp3, ref tempVel);
Solve3d(up, sp1, sp2, sp3, ref tempVel);
velocity = tempVel;
return;
}
default:
{
// Can't have more than 4 and less than 1 plane
Assert.IsTrue(false);
break;
}
}
}