forked from CesiumGS/cesium
-
Notifications
You must be signed in to change notification settings - Fork 0
/
CylinderGeometryLibrary.js
59 lines (52 loc) · 1.43 KB
/
CylinderGeometryLibrary.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
import CesiumMath from "./Math.js";
/**
* @private
*/
const CylinderGeometryLibrary = {};
/**
* @private
*/
CylinderGeometryLibrary.computePositions = function (
length,
topRadius,
bottomRadius,
slices,
fill
) {
const topZ = length * 0.5;
const bottomZ = -topZ;
const twoSlice = slices + slices;
const size = fill ? 2 * twoSlice : twoSlice;
const positions = new Float64Array(size * 3);
let i;
let index = 0;
let tbIndex = 0;
const bottomOffset = fill ? twoSlice * 3 : 0;
const topOffset = fill ? (twoSlice + slices) * 3 : slices * 3;
for (i = 0; i < slices; i++) {
const angle = (i / slices) * CesiumMath.TWO_PI;
const x = Math.cos(angle);
const y = Math.sin(angle);
const bottomX = x * bottomRadius;
const bottomY = y * bottomRadius;
const topX = x * topRadius;
const topY = y * topRadius;
positions[tbIndex + bottomOffset] = bottomX;
positions[tbIndex + bottomOffset + 1] = bottomY;
positions[tbIndex + bottomOffset + 2] = bottomZ;
positions[tbIndex + topOffset] = topX;
positions[tbIndex + topOffset + 1] = topY;
positions[tbIndex + topOffset + 2] = topZ;
tbIndex += 3;
if (fill) {
positions[index++] = bottomX;
positions[index++] = bottomY;
positions[index++] = bottomZ;
positions[index++] = topX;
positions[index++] = topY;
positions[index++] = topZ;
}
}
return positions;
};
export default CylinderGeometryLibrary;