float3 Frustum::CornerPoint(int cornerIndex) const
{
assume(0 <= cornerIndex && cornerIndex <= 7);
switch(cornerIndex)
{
default: // For release builds where assume() is disabled, return always the first option if out-of-bounds.
case 0: return NearPlanePos(-1, -1);
case 1: return FarPlanePos(-1, -1);
case 2: return NearPlanePos(-1, 1);
case 3: return FarPlanePos(-1, 1);
case 4: return NearPlanePos(1, -1);
case 5: return FarPlanePos(1, -1);
case 6: return NearPlanePos(1, 1);
case 7: return FarPlanePos(1, 1);
}
}
Plane Frustum::BottomPlane() const
{
if (type == PerspectiveFrustum)
{
vec bottomSide = front - Tan(verticalFov * 0.5f) * up;
vec left = -WorldRight();
vec bottomSideNormal = ((handedness == FrustumRightHanded) ? Cross(left, bottomSide) : Cross(bottomSide, left)).Normalized();
return Plane(pos, bottomSideNormal);
}
else
{
return Plane(NearPlanePos(0.f, -1.f), -up);
}
}
Ray Frustum::UnProject(float x, float y) const
{
assume(x >= -1.f);
assume(x <= 1.f);
assume(y >= -1.f);
assume(y <= 1.f);
if (type == PerspectiveFrustum)
{
float3 nearPlanePos = NearPlanePos(x, y);
return Ray(pos, (nearPlanePos - pos).Normalized());
}
else
return UnProjectFromNearPlane(x, y);
}
Plane Frustum::TopPlane() const
{
if (type == PerspectiveFrustum)
{
vec topSide = front + Tan(verticalFov * 0.5f) * up;
vec right = WorldRight();
vec topSideNormal = ((handedness == FrustumRightHanded) ? Cross(right, topSide) : Cross(topSide, right)).Normalized();
return Plane(pos, topSideNormal);
}
else
{
return Plane(NearPlanePos(0.f, 1.f), up);
}
}
Plane Frustum::RightPlane() const
{
if (type == PerspectiveFrustum)
{
vec right = WorldRight();
right.ScaleToLength(Tan(horizontalFov*0.5f));
vec rightSide = front + right;
vec rightSideNormal = ((handedness == FrustumRightHanded) ? Cross(rightSide, up) : Cross(up, rightSide)).Normalized();
return Plane(pos, rightSideNormal);
}
else
{
vec right = WorldRight();
return Plane(NearPlanePos(1.f, 0.f), right.Normalized());
}
}
Plane Frustum::LeftPlane() const
{
if (type == PerspectiveFrustum)
{
vec left = -WorldRight();
left.ScaleToLength(Tan(horizontalFov*0.5f));
vec leftSide = front + left;
vec leftSideNormal = ((handedness == FrustumRightHanded) ? Cross(up, leftSide) : Cross(leftSide, up)).Normalized();
return Plane(pos, leftSideNormal);
}
else
{
vec left = -WorldRight();
return Plane(NearPlanePos(-1.f, 0.f), left.Normalized());
}
}
int Frustum::UniqueEdgeDirections(vec *out) const
{
if (type == PerspectiveFrustum)
{
out[0] = NearPlanePos(-1, -1) - NearPlanePos(1, -1);
out[1] = NearPlanePos(-1, -1) - NearPlanePos(-1, 1);
out[2] = FarPlanePos(-1, -1) - NearPlanePos(-1, -1);
out[3] = FarPlanePos( 1, -1) - NearPlanePos( 1, -1);
out[4] = FarPlanePos(-1, 1) - NearPlanePos(-1, 1);
out[5] = FarPlanePos( 1, 1) - NearPlanePos( 1, 1);
return 6;
}
else
{
out[0] = front;
out[1] = up;
out[2] = Cross(front, up);
return 3;
}
}
Ray Frustum::LookAt(float x, float y) const
{
float3 nearPlanePos = NearPlanePos(x, y);
return Ray(pos, (nearPlanePos - pos).Normalized());
}
LineSegment Frustum::UnProjectLineSegment(float x, float y) const
{
float3 nearPlanePos = NearPlanePos(x, y);
float3 farPlanePos = FarPlanePos(x, y);
return LineSegment(nearPlanePos, farPlanePos);
}
float3 Frustum::NearPlanePos(const float2 &point) const
{
return NearPlanePos(point.x, point.y);
}
