https://planetazip.ru/wp-content/plugins/3d-scene-viewer/assets/js/3js/src/core/GLBufferAttribute.js

1/**
2 * An alternative version of a buffer attribute with more control over the VBO.
3 *
4 * The renderer does not construct a VBO for this kind of attribute. Instead, it uses
5 * whatever VBO is passed in constructor and can later be altered via the `buffer` property.
6 *
7 * The most common use case for this class is when some kind of GPGPU calculation interferes
8 * or even produces the VBOs in question.
9 *
10 * Notice that this class can only be used with {@link WebGLRenderer}.
11 */
12class GLBufferAttribute {
13
14	/**
15	 * Constructs a new GL buffer attribute.
16	 *
17	 * @param {WebGLBuffer} buffer - The native WebGL buffer.
18	 * @param {number} type - The native data type (e.g. `gl.FLOAT`).
19	 * @param {number} itemSize - The item size.
20	 * @param {number} elementSize - The corresponding size (in bytes) for the given `type` parameter.
21	 * @param {number} count - The expected number of vertices in VBO.
22	 * @param {boolean} [normalized=false] - Whether the data are normalized or not.
23	 */
24	constructor( buffer, type, itemSize, elementSize, count, normalized = false ) {
25
26		/**
27		 * This flag can be used for type testing.
28		 *
29		 * @type {boolean}
30		 * @readonly
31		 * @default true
32		 */
33		this.isGLBufferAttribute = true;
34
35		/**
36		 * The name of the buffer attribute.
37		 *
38		 * @type {string}
39		 */
40		this.name = '';
41
42		/**
43		 * The native WebGL buffer.
44		 *
45		 * @type {WebGLBuffer}
46		 */
47		this.buffer = buffer;
48
49		/**
50		 * The native data type.
51		 *
52		 * @type {number}
53		 */
54		this.type = type;
55
56		/**
57		 * The item size, see {@link BufferAttribute#itemSize}.
58		 *
59		 * @type {number}
60		 */
61		this.itemSize = itemSize;
62
63		/**
64		 * The corresponding size (in bytes) for the given `type` parameter.
65		 *
66		 * @type {number}
67		 */
68		this.elementSize = elementSize;
69
70		/**
71		 * The expected number of vertices in VBO.
72		 *
73		 * @type {number}
74		 */
75		this.count = count;
76
77		/**
78		 * Applies to integer data only. Indicates how the underlying data in the buffer maps to
79		 * the values in the GLSL code. For instance, if `buffer` contains data of `gl.UNSIGNED_SHORT`,
80		 * and `normalized` is `true`, the values `0 - +65535` in the buffer data will be mapped to
81		 * `0.0f - +1.0f` in the GLSL attribute. If `normalized` is `false`, the values will be converted
82		 * to floats unmodified, i.e. `65535` becomes `65535.0f`.
83		 *
84		 * @type {boolean}
85		 */
86		this.normalized = normalized;
87
88		/**
89		 * A version number, incremented every time the `needsUpdate` is set to `true`.
90		 *
91		 * @type {number}
92		 */
93		this.version = 0;
94
95	}
96
97	/**
98	 * Flag to indicate that this attribute has changed and should be re-sent to
99	 * the GPU. Set this to `true` when you modify the value of the array.
100	 *
101	 * @type {number}
102	 * @default false
103	 * @param {boolean} value
104	 */
105	set needsUpdate( value ) {
106
107		if ( value === true ) this.version ++;
108
109	}
110
111	/**
112	 * Sets the given native WebGL buffer.
113	 *
114	 * @param {WebGLBuffer} buffer - The buffer to set.
115	 * @return {BufferAttribute} A reference to this instance.
116	 */
117	setBuffer( buffer ) {
118
119		this.buffer = buffer;
120
121		return this;
122
123	}
124
125	/**
126	 * Sets the given native data type and element size.
127	 *
128	 * @param {number} type - The native data type (e.g. `gl.FLOAT`).
129	 * @param {number} elementSize - The corresponding size (in bytes) for the given `type` parameter.
130	 * @return {BufferAttribute} A reference to this instance.
131	 */
132	setType( type, elementSize ) {
133
134		this.type = type;
135		this.elementSize = elementSize;
136
137		return this;
138
139	}
140
141	/**
142	 * Sets the item size.
143	 *
144	 * @param {number} itemSize - The item size.
145	 * @return {BufferAttribute} A reference to this instance.
146	 */
147	setItemSize( itemSize ) {
148
149		this.itemSize = itemSize;
150
151		return this;
152
153	}
154
155	/**
156	 * Sets the count (the expected number of vertices in VBO).
157	 *
158	 * @param {number} count - The count.
159	 * @return {BufferAttribute} A reference to this instance.
160	 */
161	setCount( count ) {
162
163		this.count = count;
164
165		return this;
166
167	}
168
169}
170
171export { GLBufferAttribute };