 float2[Class Summary] |
 x |
| y |
| zero[static][const] |
| one[static][const] |
| unitX[static][const] |
| unitY[static][const] |
| nan[static][const] |
| inf[static][const] |
 ctor (+3 overloads) |
| ptr() (+1 overload) |
 operator[](index) (+1 overload) |
| At(index) (+1 overload) |
| operators +,-,*,/(v)[const] (+1 overload) |
| operators +=,-=,*=,/=(v) |
| Add/Sub/Mul/Div(v)[const] (+1 overload) |
| xx/xy/yx/yy()[const] |
| Swizzled(i,j,k,l)[const] (+2 overloads) |
| SetFromScalar(scalar) |
| Set(x,y) |
| SetFromPolarCoordinates(theta,length) (+1 overload) |
| ToPolarCoordinates()[const] |
| AimedAngle()[const] |
| Length()[const] |
| LengthSq()[const] |
| Normalize() |
| Normalized()[const] |
| ScaleToLength(newLength) |
| ScaledToLength(newLength)[const] |
| IsNormalized(epsilonSq)[const] |
| IsZero(epsilonSq)[const] |
| IsFinite()[const] |
| IsPerpendicular(other,epsilonSq)[const] |
| Equals(other,epsilon)[const] (+1 overload) |
| BitEquals(other)[const] |
| ToString()[const] |
| SerializeToString()[const] |
| SerializeToCodeString()[const] |
| SumOfElements()[const] |
| ProductOfElements()[const] |
| AverageOfElements()[const] |
| MinElement()[const] |
| MinElementIndex()[const] |
| MaxElement()[const] |
| MaxElementIndex()[const] |
| Abs()[const] |
| Neg()[const] |
| Recip()[const] |
| Min(ceil)[const] (+1 overload) |
| Max(floor)[const] (+1 overload) |
| Clamp(floor,ceil)[const] (+1 overload) |
| Clamp01()[const] |
| Distance(point)[const] |
| DistanceSq(point)[const] |
| Dot(v)[const] |
| Perp()[const] |
| PerpDot(rhs)[const] |
| Rotate90CW() |
| Rotated90CW()[const] |
| Rotate90CCW() |
| Rotated90CCW()[const] |
| Reflect(normal)[const] |
| Refract(...)[const] |
| ProjectTo(direction)[const] |
| ProjectToNorm(direction)[const] |
| AngleBetween(other)[const] |
| AngleBetweenNorm(normalizedVector)[const] |
| Decompose(...)[const] |
| Lerp(b,t)[const] |
| FromScalar(scalar)[static] |
| FromPolarCoordinates(theta,length)[static] (+1 overload) |
| FromString(str,outEndStr)[static] (+1 overload) |
| Lerp(a,b,t)[static] |
| Orthogonalize(a,b)[static] |
| AreOrthogonal(a,b,epsilon)[static] |
| Orthonormalize(a,b)[static] |
| OrientedCCW(a,b,c)[static] |
| ConvexHull(...)[static] |
| ConvexHullInPlace(...)[static] |
| ConvexHullContains(...)[static] |
| MinAreaRectInPlace(...)[static] |
| RandomDir(lcg,length)[static] |
| RandomBox(...)[static] |
float2::ConvexHullInPlace
Syntax
int float2::ConvexHullInPlace(float2 *pointArray, int numPoints); [104 lines of code]Computes the 2D convex hull of the given point set, in-place.
This function implements the Graham's Scan algorithm for finding the convex hull of a 2D point set.
This version of the algorithm works in-place, meaning that when the algorithm finishes, pointArray will contain the list of the points on the convex hull. The running time is O(nlogn). For details, see "Introduction to Algorithms, 2nd ed.", by Cormen, Leiserson, Rivest, p.824, or a lecture by Shai Simonson: http://www.aduni.org/courses/algorithms/index.php?view=cw , lecture 02-13-01.
Note
As a convention, the convex hull winds counter-clockwise when graphed in the xy plane where +x points to the right and +y points up. That is, walking along the polylist intArray[0] -> pointArray[1] -> pointArray[2] -> ... -> pointArray[numPoints-1] -> pointArray[0] performs a counter-clockwise tour.
Parameters
float2 *pointArray [in, out]A pointer to an array of numPoints float2 points that represent a point cloud. This array will be rewritten to contain the convex hull of the original point set.
Return Value
The number of points on the convex hull, i.e. the number of elements used in pointArray after the operation.