Accueil / npm / three@0.186.1 / src / core / GLBufferAttribute.js
GLBufferAttribute.js
/**
* An alternative version of a buffer attribute with more control over the VBO.
*
* The renderer does not construct a VBO for this kind of attribute. Instead, it uses
* whatever VBO is passed in constructor and can later be altered via the `buffer` property.
*
* The most common use case for this class is when some kind of GPGPU calculation interferes
* or even produces the VBOs in question.
*
* Notice that this class can only be used with {@link WebGLRenderer}.
*/
class GLBufferAttribute {
/**
* Constructs a new GL buffer attribute.
*
* @param {WebGLBuffer} buffer - The native WebGL buffer.
* @param {number} type - The native data type (e.g. `gl.FLOAT`).
* @param {number} itemSize - The item size.
* @param {number} elementSize - The corresponding size (in bytes) for the given `type` parameter.
* @param {number} count - The expected number of vertices in VBO.
* @param {boolean} [normalized=false] - Whether the data are normalized or not.
*/
constructor( buffer, type, itemSize, elementSize, count, normalized = false ) {
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
*/
this.isGLBufferAttribute = true;
/**
* The name of the buffer attribute.
*
* @type {string}
*/
this.name = '';
/**
* The native WebGL buffer.
*
* @type {WebGLBuffer}
*/
this.buffer = buffer;
/**
* The native data type.
*
* @type {number}
*/
this.type = type;
/**
* The item size, see {@link BufferAttribute#itemSize}.
*
* @type {number}
*/
this.itemSize = itemSize;
/**
* The corresponding size (in bytes) for the given `type` parameter.
*
* @type {number}
*/
this.elementSize = elementSize;
/**
* The expected number of vertices in VBO.
*
* @type {number}
*/
this.count = count;
/**
* Applies to integer data only. Indicates how the underlying data in the buffer maps to
* the values in the GLSL code. For instance, if `buffer` contains data of `gl.UNSIGNED_SHORT`,
* and `normalized` is `true`, the values `0 - +65535` in the buffer data will be mapped to
* `0.0f - +1.0f` in the GLSL attribute. If `normalized` is `false`, the values will be converted
* to floats unmodified, i.e. `65535` becomes `65535.0f`.
*
* @type {boolean}
*/
this.normalized = normalized;
/**
* A version number, incremented every time the `needsUpdate` is set to `true`.
*
* @type {number}
*/
this.version = 0;
}
/**
* Flag to indicate that this attribute has changed and should be re-sent to
* the GPU. Set this to `true` when you modify the value of the array.
*
* @type {number}
* @default false
* @param {boolean} value
*/
set needsUpdate( value ) {
if ( value === true ) this.version ++;
}
/**
* Sets the given native WebGL buffer.
*
* @param {WebGLBuffer} buffer - The buffer to set.
* @return {BufferAttribute} A reference to this instance.
*/
setBuffer( buffer ) {
this.buffer = buffer;
return this;
}
/**
* Sets the given native data type and element size.
*
* @param {number} type - The native data type (e.g. `gl.FLOAT`).
* @param {number} elementSize - The corresponding size (in bytes) for the given `type` parameter.
* @return {BufferAttribute} A reference to this instance.
*/
setType( type, elementSize ) {
this.type = type;
this.elementSize = elementSize;
return this;
}
/**
* Sets the item size.
*
* @param {number} itemSize - The item size.
* @return {BufferAttribute} A reference to this instance.
*/
setItemSize( itemSize ) {
this.itemSize = itemSize;
return this;
}
/**
* Sets the count (the expected number of vertices in VBO).
*
* @param {number} count - The count.
* @return {BufferAttribute} A reference to this instance.
*/
setCount( count ) {
this.count = count;
return this;
}
}
export { GLBufferAttribute };