方法
static Cesium.Intersections2D.clipTriangleAtAxisAlignedThreshold(threshold, keepAbove, u0, u1, u2, result) → Array.<number>
Splits a 2D triangle at given axis-aligned threshold value and returns the resulting
polygon on a given side of the threshold. The resulting polygon may have 0, 1, 2,
3, or 4 vertices.
| 参数名称 | 类型 | 描述信息 |
|---|---|---|
threshold |
number | The threshold coordinate value at which to clip the triangle. |
keepAbove |
boolean | true to keep the portion of the triangle above the threshold, or false to keep the portion below. |
u0 |
number | The coordinate of the first vertex in the triangle, in counter-clockwise order. |
u1 |
number | The coordinate of the second vertex in the triangle, in counter-clockwise order. |
u2 |
number | The coordinate of the third vertex in the triangle, in counter-clockwise order. |
result |
Array.<number> | 可选 The array into which to copy the result. If this parameter is not supplied, a new array is constructed and returned. |
返回值:
The polygon that results after the clip, specified as a list of
vertices. The vertices are specified in counter-clockwise order.
Each vertex is either an index from the existing list (identified as
a 0, 1, or 2) or -1 indicating a new vertex not in the original triangle.
For new vertices, the -1 is followed by three additional numbers: the
index of each of the two original vertices forming the line segment that
the new vertex lies on, and the fraction of the distance from the first
vertex to the second one.
使用示例:
const result = Cesium.Intersections2D.clipTriangleAtAxisAlignedThreshold(0.5, false, 0.2, 0.6, 0.4);
// result === [2, 0, -1, 1, 0, 0.25, -1, 1, 2, 0.5]static Cesium.Intersections2D.computeBarycentricCoordinates(x, y, x1, y1, x2, y2, x3, y3, result) → Cartesian3
Compute the barycentric coordinates of a 2D position within a 2D triangle.
| 参数名称 | 类型 | 描述信息 |
|---|---|---|
x |
number | The x coordinate of the position for which to find the barycentric coordinates. |
y |
number | The y coordinate of the position for which to find the barycentric coordinates. |
x1 |
number | The x coordinate of the triangle's first vertex. |
y1 |
number | The y coordinate of the triangle's first vertex. |
x2 |
number | The x coordinate of the triangle's second vertex. |
y2 |
number | The y coordinate of the triangle's second vertex. |
x3 |
number | The x coordinate of the triangle's third vertex. |
y3 |
number | The y coordinate of the triangle's third vertex. |
result |
Cartesian3 | 可选 The instance into to which to copy the result. If this parameter is undefined, a new instance is created and returned. |
返回值:
The barycentric coordinates of the position within the triangle.
使用示例:
const result = Cesium.Intersections2D.computeBarycentricCoordinates(0.0, 0.0, 0.0, 1.0, -1, -0.5, 1, -0.5);
// result === new Cesium.Cartesian3(1.0 / 3.0, 1.0 / 3.0, 1.0 / 3.0);static Cesium.Intersections2D.computeLineSegmentLineSegmentIntersection(x00, y00, x01, y01, x10, y10, x11, y11, result) → Cartesian2
Compute the intersection between 2 line segments
| 参数名称 | 类型 | 描述信息 |
|---|---|---|
x00 |
number | The x coordinate of the first line's first vertex. |
y00 |
number | The y coordinate of the first line's first vertex. |
x01 |
number | The x coordinate of the first line's second vertex. |
y01 |
number | The y coordinate of the first line's second vertex. |
x10 |
number | The x coordinate of the second line's first vertex. |
y10 |
number | The y coordinate of the second line's first vertex. |
x11 |
number | The x coordinate of the second line's second vertex. |
y11 |
number | The y coordinate of the second line's second vertex. |
result |
Cartesian2 | 可选 The instance into to which to copy the result. If this parameter is undefined, a new instance is created and returned. |
返回值:
The intersection point, undefined if there is no intersection point or lines are coincident.
使用示例:
const result = Cesium.Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, -1, 1, 1, 1);
// result === new Cesium.Cartesian2(0.0, 1.0);