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📄 TeapotGeometry.js

📊 Analysis Summary

Metric Count
🔧 Functions 1
🧱 Classes 1
📦 Imports 5
📊 Variables & Constants 52

📚 Table of Contents

🛠️ File Location:

📂 examples/jsm/geometries/TeapotGeometry.js

📦 Imports

Name Source
BufferAttribute three
BufferGeometry three
Matrix4 three
Vector3 three
Vector4 three

Variables & Constants

Name Type Kind Value Exported
teapotPatches number[] let/var [ /*rim*/ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 3, 16, 17, 18...
teapotVertices number[] let/var [ 1.4, 0, 2.4, 1.4, - 0.784, 2.4, 0.784, - 1.4, 2.4, 0, - 1.4, 2.4, 1.3375, 0...
blinnScale 1.3 let/var 1.3
maxHeight number let/var 3.15 * ( blinn ? 1 : blinnScale )
maxHeight2 number let/var maxHeight / 2
trueSize number let/var size / maxHeight2
numTriangles number let/var bottom ? ( 8 * segments - 4 ) * segments : 0
indices Uint32Array<ArrayBuffer> let/var new Uint32Array( numTriangles * 3 )
numVertices number let/var bottom ? 4 : 0
vertices Float32Array<ArrayBuffer> let/var new Float32Array( numVertices * 3 )
normals Float32Array<ArrayBuffer> let/var new Float32Array( numVertices * 3 )
uvs Float32Array<ArrayBuffer> let/var new Float32Array( numVertices * 2 )
ms any let/var new Matrix4()
g any[] let/var []
sp any[] let/var []
tp any[] let/var []
dsp any[] let/var []
dtp any[] let/var []
mgm any[] let/var []
vert any[] let/var []
sdir any[] let/var []
tdir any[] let/var []
norm any let/var new Vector3()
tcoord any let/var *not shown*
sval any let/var *not shown*
tval any let/var *not shown*
p any let/var *not shown*
dsval number let/var 0
dtval number let/var 0
normOut any let/var new Vector3()
gmx any let/var new Matrix4()
tmtx any let/var new Matrix4()
vsp any let/var new Vector4()
vtp any let/var new Vector4()
vdsp any let/var new Vector4()
vdtp any let/var new Vector4()
vsdir any let/var new Vector3()
vtdir any let/var new Vector3()
minPatches 0 \| 20 let/var body ? 0 : 20
maxPatches 32 \| 28 let/var bottom ? 32 : 28
vertPerRow number let/var segments + 1
surfCount number let/var 0
vertCount number let/var 0
normCount number let/var 0
uvCount number let/var 0
indexCount number let/var 0
s number let/var sstep / segments
t number let/var tstep / segments
v1 number let/var surfCount * vertPerRow * vertPerRow + sstep * vertPerRow + tstep
v2 number let/var v1 + 1
v3 number let/var v2 + vertPerRow
v4 number let/var v1 + vertPerRow

Functions

notDegenerate(vtx1: any, vtx2: any, vtx3: any): boolean

Parameters:

  • vtx1 any
  • vtx2 any
  • vtx3 any

Returns: boolean

Code
( vtx1, vtx2, vtx3 ) => // if any vertex matches, return false
            ! ( ( ( vertices[ vtx1 * 3 ] === vertices[ vtx2 * 3 ] ) &&
                    ( vertices[ vtx1 * 3 + 1 ] === vertices[ vtx2 * 3 + 1 ] ) &&
                    ( vertices[ vtx1 * 3 + 2 ] === vertices[ vtx2 * 3 + 2 ] ) ) ||
                    ( ( vertices[ vtx1 * 3 ] === vertices[ vtx3 * 3 ] ) &&
                    ( vertices[ vtx1 * 3 + 1 ] === vertices[ vtx3 * 3 + 1 ] ) &&
                    ( vertices[ vtx1 * 3 + 2 ] === vertices[ vtx3 * 3 + 2 ] ) ) || ( vertices[ vtx2 * 3 ] === vertices[ vtx3 * 3 ] ) &&
                    ( vertices[ vtx2 * 3 + 1 ] === vertices[ vtx3 * 3 + 1 ] ) &&
                    ( vertices[ vtx2 * 3 + 2 ] === vertices[ vtx3 * 3 + 2 ] ) )

Classes

TeapotGeometry

Class Code
class TeapotGeometry extends BufferGeometry {

    /**
     * Constructs a new teapot geometry.
     *
     * @param {number} [size=50] - Relative scale of the teapot.
     * @param {number} [segments=10] - Number of line segments to subdivide each patch edge.
     * @param {boolean} [bottom=true] - Whether the bottom of the teapot is generated or not.
     * @param {boolean} [lid=true] - Whether the lid is generated or not.
     * @param {boolean} [body=true] - Whether the body is generated or not.
     * @param {boolean} [fitLid=true] - Whether the lid is slightly stretched to prevent gaps between the body and lid or not.
     * @param {boolean} [blinn=true] -  Whether the teapot is scaled vertically for better aesthetics or not.
     */
    constructor( size = 50, segments = 10, bottom = true, lid = true, body = true, fitLid = true, blinn = true ) {

        // 32 * 4 * 4 Bezier spline patches
        const teapotPatches = [
            /*rim*/
            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
            3, 16, 17, 18, 7, 19, 20, 21, 11, 22, 23, 24, 15, 25, 26, 27,
            18, 28, 29, 30, 21, 31, 32, 33, 24, 34, 35, 36, 27, 37, 38, 39,
            30, 40, 41, 0, 33, 42, 43, 4, 36, 44, 45, 8, 39, 46, 47, 12,
            /*body*/
            12, 13, 14, 15, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
            15, 25, 26, 27, 51, 60, 61, 62, 55, 63, 64, 65, 59, 66, 67, 68,
            27, 37, 38, 39, 62, 69, 70, 71, 65, 72, 73, 74, 68, 75, 76, 77,
            39, 46, 47, 12, 71, 78, 79, 48, 74, 80, 81, 52, 77, 82, 83, 56,
            56, 57, 58, 59, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,
            59, 66, 67, 68, 87, 96, 97, 98, 91, 99, 100, 101, 95, 102, 103, 104,
            68, 75, 76, 77, 98, 105, 106, 107, 101, 108, 109, 110, 104, 111, 112, 113,
            77, 82, 83, 56, 107, 114, 115, 84, 110, 116, 117, 88, 113, 118, 119, 92,
            /*handle*/
            120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,
            123, 136, 137, 120, 127, 138, 139, 124, 131, 140, 141, 128, 135, 142, 143, 132,
            132, 133, 134, 135, 144, 145, 146, 147, 148, 149, 150, 151, 68, 152, 153, 154,
            135, 142, 143, 132, 147, 155, 156, 144, 151, 157, 158, 148, 154, 159, 160, 68,
            /*spout*/
            161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176,
            164, 177, 178, 161, 168, 179, 180, 165, 172, 181, 182, 169, 176, 183, 184, 173,
            173, 174, 175, 176, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196,
            176, 183, 184, 173, 188, 197, 198, 185, 192, 199, 200, 189, 196, 201, 202, 193,
            /*lid*/
            203, 203, 203, 203, 204, 205, 206, 207, 208, 208, 208, 208, 209, 210, 211, 212,
            203, 203, 203, 203, 207, 213, 214, 215, 208, 208, 208, 208, 212, 216, 217, 218,
            203, 203, 203, 203, 215, 219, 220, 221, 208, 208, 208, 208, 218, 222, 223, 224,
            203, 203, 203, 203, 221, 225, 226, 204, 208, 208, 208, 208, 224, 227, 228, 209,
            209, 210, 211, 212, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240,
            212, 216, 217, 218, 232, 241, 242, 243, 236, 244, 245, 246, 240, 247, 248, 249,
            218, 222, 223, 224, 243, 250, 251, 252, 246, 253, 254, 255, 249, 256, 257, 258,
            224, 227, 228, 209, 252, 259, 260, 229, 255, 261, 262, 233, 258, 263, 264, 237,
            /*bottom*/
            265, 265, 265, 265, 266, 267, 268, 269, 270, 271, 272, 273, 92, 119, 118, 113,
            265, 265, 265, 265, 269, 274, 275, 276, 273, 277, 278, 279, 113, 112, 111, 104,
            265, 265, 265, 265, 276, 280, 281, 282, 279, 283, 284, 285, 104, 103, 102, 95,
            265, 265, 265, 265, 282, 286, 287, 266, 285, 288, 289, 270, 95, 94, 93, 92
        ];

        const teapotVertices = [
            1.4, 0, 2.4,
            1.4, - 0.784, 2.4,
            0.784, - 1.4, 2.4,
            0, - 1.4, 2.4,
            1.3375, 0, 2.53125,
            1.3375, - 0.749, 2.53125,
            0.749, - 1.3375, 2.53125,
            0, - 1.3375, 2.53125,
            1.4375, 0, 2.53125,
            1.4375, - 0.805, 2.53125,
            0.805, - 1.4375, 2.53125,
            0, - 1.4375, 2.53125,
            1.5, 0, 2.4,
            1.5, - 0.84, 2.4,
            0.84, - 1.5, 2.4,
            0, - 1.5, 2.4,
            - 0.784, - 1.4, 2.4,
            - 1.4, - 0.784, 2.4,
            - 1.4, 0, 2.4,
            - 0.749, - 1.3375, 2.53125,
            - 1.3375, - 0.749, 2.53125,
            - 1.3375, 0, 2.53125,
            - 0.805, - 1.4375, 2.53125,
            - 1.4375, - 0.805, 2.53125,
            - 1.4375, 0, 2.53125,
            - 0.84, - 1.5, 2.4,
            - 1.5, - 0.84, 2.4,
            - 1.5, 0, 2.4,
            - 1.4, 0.784, 2.4,
            - 0.784, 1.4, 2.4,
            0, 1.4, 2.4,
            - 1.3375, 0.749, 2.53125,
            - 0.749, 1.3375, 2.53125,
            0, 1.3375, 2.53125,
            - 1.4375, 0.805, 2.53125,
            - 0.805, 1.4375, 2.53125,
            0, 1.4375, 2.53125,
            - 1.5, 0.84, 2.4,
            - 0.84, 1.5, 2.4,
            0, 1.5, 2.4,
            0.784, 1.4, 2.4,
            1.4, 0.784, 2.4,
            0.749, 1.3375, 2.53125,
            1.3375, 0.749, 2.53125,
            0.805, 1.4375, 2.53125,
            1.4375, 0.805, 2.53125,
            0.84, 1.5, 2.4,
            1.5, 0.84, 2.4,
            1.75, 0, 1.875,
            1.75, - 0.98, 1.875,
            0.98, - 1.75, 1.875,
            0, - 1.75, 1.875,
            2, 0, 1.35,
            2, - 1.12, 1.35,
            1.12, - 2, 1.35,
            0, - 2, 1.35,
            2, 0, 0.9,
            2, - 1.12, 0.9,
            1.12, - 2, 0.9,
            0, - 2, 0.9,
            - 0.98, - 1.75, 1.875,
            - 1.75, - 0.98, 1.875,
            - 1.75, 0, 1.875,
            - 1.12, - 2, 1.35,
            - 2, - 1.12, 1.35,
            - 2, 0, 1.35,
            - 1.12, - 2, 0.9,
            - 2, - 1.12, 0.9,
            - 2, 0, 0.9,
            - 1.75, 0.98, 1.875,
            - 0.98, 1.75, 1.875,
            0, 1.75, 1.875,
            - 2, 1.12, 1.35,
            - 1.12, 2, 1.35,
            0, 2, 1.35,
            - 2, 1.12, 0.9,
            - 1.12, 2, 0.9,
            0, 2, 0.9,
            0.98, 1.75, 1.875,
            1.75, 0.98, 1.875,
            1.12, 2, 1.35,
            2, 1.12, 1.35,
            1.12, 2, 0.9,
            2, 1.12, 0.9,
            2, 0, 0.45,
            2, - 1.12, 0.45,
            1.12, - 2, 0.45,
            0, - 2, 0.45,
            1.5, 0, 0.225,
            1.5, - 0.84, 0.225,
            0.84, - 1.5, 0.225,
            0, - 1.5, 0.225,
            1.5, 0, 0.15,
            1.5, - 0.84, 0.15,
            0.84, - 1.5, 0.15,
            0, - 1.5, 0.15,
            - 1.12, - 2, 0.45,
            - 2, - 1.12, 0.45,
            - 2, 0, 0.45,
            - 0.84, - 1.5, 0.225,
            - 1.5, - 0.84, 0.225,
            - 1.5, 0, 0.225,
            - 0.84, - 1.5, 0.15,
            - 1.5, - 0.84, 0.15,
            - 1.5, 0, 0.15,
            - 2, 1.12, 0.45,
            - 1.12, 2, 0.45,
            0, 2, 0.45,
            - 1.5, 0.84, 0.225,
            - 0.84, 1.5, 0.225,
            0, 1.5, 0.225,
            - 1.5, 0.84, 0.15,
            - 0.84, 1.5, 0.15,
            0, 1.5, 0.15,
            1.12, 2, 0.45,
            2, 1.12, 0.45,
            0.84, 1.5, 0.225,
            1.5, 0.84, 0.225,
            0.84, 1.5, 0.15,
            1.5, 0.84, 0.15,
            - 1.6, 0, 2.025,
            - 1.6, - 0.3, 2.025,
            - 1.5, - 0.3, 2.25,
            - 1.5, 0, 2.25,
            - 2.3, 0, 2.025,
            - 2.3, - 0.3, 2.025,
            - 2.5, - 0.3, 2.25,
            - 2.5, 0, 2.25,
            - 2.7, 0, 2.025,
            - 2.7, - 0.3, 2.025,
            - 3, - 0.3, 2.25,
            - 3, 0, 2.25,
            - 2.7, 0, 1.8,
            - 2.7, - 0.3, 1.8,
            - 3, - 0.3, 1.8,
            - 3, 0, 1.8,
            - 1.5, 0.3, 2.25,
            - 1.6, 0.3, 2.025,
            - 2.5, 0.3, 2.25,
            - 2.3, 0.3, 2.025,
            - 3, 0.3, 2.25,
            - 2.7, 0.3, 2.025,
            - 3, 0.3, 1.8,
            - 2.7, 0.3, 1.8,
            - 2.7, 0, 1.575,
            - 2.7, - 0.3, 1.575,
            - 3, - 0.3, 1.35,
            - 3, 0, 1.35,
            - 2.5, 0, 1.125,
            - 2.5, - 0.3, 1.125,
            - 2.65, - 0.3, 0.9375,
            - 2.65, 0, 0.9375,
            - 2, - 0.3, 0.9,
            - 1.9, - 0.3, 0.6,
            - 1.9, 0, 0.6,
            - 3, 0.3, 1.35,
            - 2.7, 0.3, 1.575,
            - 2.65, 0.3, 0.9375,
            - 2.5, 0.3, 1.125,
            - 1.9, 0.3, 0.6,
            - 2, 0.3, 0.9,
            1.7, 0, 1.425,
            1.7, - 0.66, 1.425,
            1.7, - 0.66, 0.6,
            1.7, 0, 0.6,
            2.6, 0, 1.425,
            2.6, - 0.66, 1.425,
            3.1, - 0.66, 0.825,
            3.1, 0, 0.825,
            2.3, 0, 2.1,
            2.3, - 0.25, 2.1,
            2.4, - 0.25, 2.025,
            2.4, 0, 2.025,
            2.7, 0, 2.4,
            2.7, - 0.25, 2.4,
            3.3, - 0.25, 2.4,
            3.3, 0, 2.4,
            1.7, 0.66, 0.6,
            1.7, 0.66, 1.425,
            3.1, 0.66, 0.825,
            2.6, 0.66, 1.425,
            2.4, 0.25, 2.025,
            2.3, 0.25, 2.1,
            3.3, 0.25, 2.4,
            2.7, 0.25, 2.4,
            2.8, 0, 2.475,
            2.8, - 0.25, 2.475,
            3.525, - 0.25, 2.49375,
            3.525, 0, 2.49375,
            2.9, 0, 2.475,
            2.9, - 0.15, 2.475,
            3.45, - 0.15, 2.5125,
            3.45, 0, 2.5125,
            2.8, 0, 2.4,
            2.8, - 0.15, 2.4,
            3.2, - 0.15, 2.4,
            3.2, 0, 2.4,
            3.525, 0.25, 2.49375,
            2.8, 0.25, 2.475,
            3.45, 0.15, 2.5125,
            2.9, 0.15, 2.475,
            3.2, 0.15, 2.4,
            2.8, 0.15, 2.4,
            0, 0, 3.15,
            0.8, 0, 3.15,
            0.8, - 0.45, 3.15,
            0.45, - 0.8, 3.15,
            0, - 0.8, 3.15,
            0, 0, 2.85,
            0.2, 0, 2.7,
            0.2, - 0.112, 2.7,
            0.112, - 0.2, 2.7,
            0, - 0.2, 2.7,
            - 0.45, - 0.8, 3.15,
            - 0.8, - 0.45, 3.15,
            - 0.8, 0, 3.15,
            - 0.112, - 0.2, 2.7,
            - 0.2, - 0.112, 2.7,
            - 0.2, 0, 2.7,
            - 0.8, 0.45, 3.15,
            - 0.45, 0.8, 3.15,
            0, 0.8, 3.15,
            - 0.2, 0.112, 2.7,
            - 0.112, 0.2, 2.7,
            0, 0.2, 2.7,
            0.45, 0.8, 3.15,
            0.8, 0.45, 3.15,
            0.112, 0.2, 2.7,
            0.2, 0.112, 2.7,
            0.4, 0, 2.55,
            0.4, - 0.224, 2.55,
            0.224, - 0.4, 2.55,
            0, - 0.4, 2.55,
            1.3, 0, 2.55,
            1.3, - 0.728, 2.55,
            0.728, - 1.3, 2.55,
            0, - 1.3, 2.55,
            1.3, 0, 2.4,
            1.3, - 0.728, 2.4,
            0.728, - 1.3, 2.4,
            0, - 1.3, 2.4,
            - 0.224, - 0.4, 2.55,
            - 0.4, - 0.224, 2.55,
            - 0.4, 0, 2.55,
            - 0.728, - 1.3, 2.55,
            - 1.3, - 0.728, 2.55,
            - 1.3, 0, 2.55,
            - 0.728, - 1.3, 2.4,
            - 1.3, - 0.728, 2.4,
            - 1.3, 0, 2.4,
            - 0.4, 0.224, 2.55,
            - 0.224, 0.4, 2.55,
            0, 0.4, 2.55,
            - 1.3, 0.728, 2.55,
            - 0.728, 1.3, 2.55,
            0, 1.3, 2.55,
            - 1.3, 0.728, 2.4,
            - 0.728, 1.3, 2.4,
            0, 1.3, 2.4,
            0.224, 0.4, 2.55,
            0.4, 0.224, 2.55,
            0.728, 1.3, 2.55,
            1.3, 0.728, 2.55,
            0.728, 1.3, 2.4,
            1.3, 0.728, 2.4,
            0, 0, 0,
            1.425, 0, 0,
            1.425, 0.798, 0,
            0.798, 1.425, 0,
            0, 1.425, 0,
            1.5, 0, 0.075,
            1.5, 0.84, 0.075,
            0.84, 1.5, 0.075,
            0, 1.5, 0.075,
            - 0.798, 1.425, 0,
            - 1.425, 0.798, 0,
            - 1.425, 0, 0,
            - 0.84, 1.5, 0.075,
            - 1.5, 0.84, 0.075,
            - 1.5, 0, 0.075,
            - 1.425, - 0.798, 0,
            - 0.798, - 1.425, 0,
            0, - 1.425, 0,
            - 1.5, - 0.84, 0.075,
            - 0.84, - 1.5, 0.075,
            0, - 1.5, 0.075,
            0.798, - 1.425, 0,
            1.425, - 0.798, 0,
            0.84, - 1.5, 0.075,
            1.5, - 0.84, 0.075
        ];

        super();

        // number of segments per patch
        segments = Math.max( 2, Math.floor( segments ) );

        // Jim Blinn scaled the teapot down in size by about 1.3 for
        // some rendering tests. He liked the new proportions that he kept
        // the data in this form. The model was distributed with these new
        // proportions and became the norm. Trivia: comparing images of the
        // real teapot and the computer model, the ratio for the bowl of the
        // real teapot is more like 1.25, but since 1.3 is the traditional
        // value given, we use it here.
        const blinnScale = 1.3;

        // scale the size to be the real scaling factor
        const maxHeight = 3.15 * ( blinn ? 1 : blinnScale );

        const maxHeight2 = maxHeight / 2;
        const trueSize = size / maxHeight2;

        // Number of elements depends on what is needed. Subtract degenerate
        // triangles at tip of bottom and lid out in advance.
        let numTriangles = bottom ? ( 8 * segments - 4 ) * segments : 0;
        numTriangles += lid ? ( 16 * segments - 4 ) * segments : 0;
        numTriangles += body ? 40 * segments * segments : 0;

        const indices = new Uint32Array( numTriangles * 3 );

        let numVertices = bottom ? 4 : 0;
        numVertices += lid ? 8 : 0;
        numVertices += body ? 20 : 0;
        numVertices *= ( segments + 1 ) * ( segments + 1 );

        const vertices = new Float32Array( numVertices * 3 );
        const normals = new Float32Array( numVertices * 3 );
        const uvs = new Float32Array( numVertices * 2 );

        // Bezier form
        const ms = new Matrix4();
        ms.set(
            - 1.0, 3.0, - 3.0, 1.0,
            3.0, - 6.0, 3.0, 0.0,
            - 3.0, 3.0, 0.0, 0.0,
            1.0, 0.0, 0.0, 0.0 );

        const g = [];

        const sp = [];
        const tp = [];
        const dsp = [];
        const dtp = [];

        // M * G * M matrix, sort of see
        // http://www.cs.helsinki.fi/group/goa/mallinnus/curves/surfaces.html
        const mgm = [];

        const vert = [];
        const sdir = [];
        const tdir = [];

        const norm = new Vector3();

        let tcoord;

        let sval;
        let tval;
        let p;
        let dsval = 0;
        let dtval = 0;

        const normOut = new Vector3();

        const gmx = new Matrix4();
        const tmtx = new Matrix4();

        const vsp = new Vector4();
        const vtp = new Vector4();
        const vdsp = new Vector4();
        const vdtp = new Vector4();

        const vsdir = new Vector3();
        const vtdir = new Vector3();

        const mst = ms.clone();
        mst.transpose();

        // internal function: test if triangle has any matching vertices;
        // if so, don't save triangle, since it won't display anything.
        const notDegenerate = ( vtx1, vtx2, vtx3 ) => // if any vertex matches, return false
            ! ( ( ( vertices[ vtx1 * 3 ] === vertices[ vtx2 * 3 ] ) &&
                    ( vertices[ vtx1 * 3 + 1 ] === vertices[ vtx2 * 3 + 1 ] ) &&
                    ( vertices[ vtx1 * 3 + 2 ] === vertices[ vtx2 * 3 + 2 ] ) ) ||
                    ( ( vertices[ vtx1 * 3 ] === vertices[ vtx3 * 3 ] ) &&
                    ( vertices[ vtx1 * 3 + 1 ] === vertices[ vtx3 * 3 + 1 ] ) &&
                    ( vertices[ vtx1 * 3 + 2 ] === vertices[ vtx3 * 3 + 2 ] ) ) || ( vertices[ vtx2 * 3 ] === vertices[ vtx3 * 3 ] ) &&
                    ( vertices[ vtx2 * 3 + 1 ] === vertices[ vtx3 * 3 + 1 ] ) &&
                    ( vertices[ vtx2 * 3 + 2 ] === vertices[ vtx3 * 3 + 2 ] ) );


        for ( let i = 0; i < 3; i ++ ) {

            mgm[ i ] = new Matrix4();

        }

        const minPatches = body ? 0 : 20;
        const maxPatches = bottom ? 32 : 28;

        const vertPerRow = segments + 1;

        let surfCount = 0;

        let vertCount = 0;
        let normCount = 0;
        let uvCount = 0;

        let indexCount = 0;

        for ( let surf = minPatches; surf < maxPatches; surf ++ ) {

            // lid is in the middle of the data, patches 20-27,
            // so ignore it for this part of the loop if the lid is not desired
            if ( lid || ( surf < 20 || surf >= 28 ) ) {

                // get M * G * M matrix for x,y,z
                for ( let i = 0; i < 3; i ++ ) {

                    // get control patches
                    for ( let r = 0; r < 4; r ++ ) {

                        for ( let c = 0; c < 4; c ++ ) {

                            // transposed
                            g[ c * 4 + r ] = teapotVertices[ teapotPatches[ surf * 16 + r * 4 + c ] * 3 + i ];

                            // is the lid to be made larger, and is this a point on the lid
                            // that is X or Y?
                            if ( fitLid && ( surf >= 20 && surf < 28 ) && ( i !== 2 ) ) {

                                // increase XY size by 7.7%, found empirically. I don't
                                // increase Z so that the teapot will continue to fit in the
                                // space -1 to 1 for Y (Y is up for the final model).
                                g[ c * 4 + r ] *= 1.077;

                            }

                            // Blinn "fixed" the teapot by dividing Z by blinnScale, and that's the
                            // data we now use. The original teapot is taller. Fix it:
                            if ( ! blinn && ( i === 2 ) ) {

                                g[ c * 4 + r ] *= blinnScale;

                            }

                        }

                    }

                    gmx.set( g[ 0 ], g[ 1 ], g[ 2 ], g[ 3 ], g[ 4 ], g[ 5 ], g[ 6 ], g[ 7 ], g[ 8 ], g[ 9 ], g[ 10 ], g[ 11 ], g[ 12 ], g[ 13 ], g[ 14 ], g[ 15 ] );

                    tmtx.multiplyMatrices( gmx, ms );
                    mgm[ i ].multiplyMatrices( mst, tmtx );

                }

                // step along, get points, and output
                for ( let sstep = 0; sstep <= segments; sstep ++ ) {

                    const s = sstep / segments;

                    for ( let tstep = 0; tstep <= segments; tstep ++ ) {

                        const t = tstep / segments;

                        // point from basis
                        // get power vectors and their derivatives
                        for ( p = 4, sval = tval = 1.0; p --; ) {

                            sp[ p ] = sval;
                            tp[ p ] = tval;
                            sval *= s;
                            tval *= t;

                            if ( p === 3 ) {

                                dsp[ p ] = dtp[ p ] = 0.0;
                                dsval = dtval = 1.0;

                            } else {

                                dsp[ p ] = dsval * ( 3 - p );
                                dtp[ p ] = dtval * ( 3 - p );
                                dsval *= s;
                                dtval *= t;

                            }

                        }

                        vsp.fromArray( sp );
                        vtp.fromArray( tp );
                        vdsp.fromArray( dsp );
                        vdtp.fromArray( dtp );

                        // do for x,y,z
                        for ( let i = 0; i < 3; i ++ ) {

                            // multiply power vectors times matrix to get value
                            tcoord = vsp.clone();
                            tcoord.applyMatrix4( mgm[ i ] );
                            vert[ i ] = tcoord.dot( vtp );

                            // get s and t tangent vectors
                            tcoord = vdsp.clone();
                            tcoord.applyMatrix4( mgm[ i ] );
                            sdir[ i ] = tcoord.dot( vtp );

                            tcoord = vsp.clone();
                            tcoord.applyMatrix4( mgm[ i ] );
                            tdir[ i ] = tcoord.dot( vdtp );

                        }

                        // find normal
                        vsdir.fromArray( sdir );
                        vtdir.fromArray( tdir );
                        norm.crossVectors( vtdir, vsdir );
                        norm.normalize();

                        // if X and Z length is 0, at the cusp, so point the normal up or down, depending on patch number
                        if ( vert[ 0 ] === 0 && vert[ 1 ] === 0 ) {

                            // if above the middle of the teapot, normal points up, else down
                            normOut.set( 0, vert[ 2 ] > maxHeight2 ? 1 : - 1, 0 );

                        } else {

                            // standard output: rotate on X axis
                            normOut.set( norm.x, norm.z, - norm.y );

                        }

                        // store it all
                        vertices[ vertCount ++ ] = trueSize * vert[ 0 ];
                        vertices[ vertCount ++ ] = trueSize * ( vert[ 2 ] - maxHeight2 );
                        vertices[ vertCount ++ ] = - trueSize * vert[ 1 ];

                        normals[ normCount ++ ] = normOut.x;
                        normals[ normCount ++ ] = normOut.y;
                        normals[ normCount ++ ] = normOut.z;

                        uvs[ uvCount ++ ] = 1 - t;
                        uvs[ uvCount ++ ] = 1 - s;

                    }

                }

                // save the faces
                for ( let sstep = 0; sstep < segments; sstep ++ ) {

                    for ( let tstep = 0; tstep < segments; tstep ++ ) {

                        const v1 = surfCount * vertPerRow * vertPerRow + sstep * vertPerRow + tstep;
                        const v2 = v1 + 1;
                        const v3 = v2 + vertPerRow;
                        const v4 = v1 + vertPerRow;

                        // Normals and UVs cannot be shared. Without clone(), you can see the consequences
                        // of sharing if you call geometry.applyMatrix4( matrix ).
                        if ( notDegenerate( v1, v2, v3 ) ) {

                            indices[ indexCount ++ ] = v1;
                            indices[ indexCount ++ ] = v2;
                            indices[ indexCount ++ ] = v3;

                        }

                        if ( notDegenerate( v1, v3, v4 ) ) {

                            indices[ indexCount ++ ] = v1;
                            indices[ indexCount ++ ] = v3;
                            indices[ indexCount ++ ] = v4;

                        }

                    }

                }

                // increment only if a surface was used
                surfCount ++;

            }

        }

        this.setIndex( new BufferAttribute( indices, 1 ) );
        this.setAttribute( 'position', new BufferAttribute( vertices, 3 ) );
        this.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );
        this.setAttribute( 'uv', new BufferAttribute( uvs, 2 ) );

        this.computeBoundingSphere();

    }

}