Accueil / npm / three@0.186.1 / src / nodes / core / IndexNode.js
IndexNode.js
import Node from './Node.js';
import { nodeImmutable } from '../tsl/TSLCore.js';
import { varying } from './VaryingNode.js';
/**
* This class represents shader indices of different types. The following predefined node
* objects cover frequent use cases:
*
* - `vertexIndex`: The index of a vertex within a mesh.
* - `instanceIndex`: The index of either a mesh instance or an invocation of a compute shader.
* - `drawIndex`: The index of a draw call.
* - `invocationLocalIndex`: The index of a compute invocation within the scope of a workgroup.
* - `invocationSubgroupIndex`: The index of a compute invocation within the scope of a subgroup.
* - `subgroupIndex`: The index of a compute invocation's subgroup within its workgroup.
*
* @augments Node
*/
class IndexNode extends Node {
static get type() {
return 'IndexNode';
}
/**
* Constructs a new index node.
*
* @param {('vertex'|'instance'|'subgroup'|'invocationLocal'|'invocationSubgroup'|'draw')} scope - The scope of the index node.
*/
constructor( scope ) {
super( 'uint' );
/**
* The scope of the index node.
*
* @type {string}
*/
this.scope = scope;
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
*/
this.isIndexNode = true;
}
generate( builder ) {
const nodeType = this.getNodeType( builder );
const scope = this.scope;
let propertyName;
if ( scope === IndexNode.VERTEX ) {
propertyName = builder.getVertexIndex();
} else if ( scope === IndexNode.INSTANCE ) {
propertyName = builder.getInstanceIndex();
} else if ( scope === IndexNode.DRAW ) {
propertyName = builder.getDrawIndex();
} else if ( scope === IndexNode.INVOCATION_LOCAL ) {
propertyName = builder.getInvocationLocalIndex();
} else if ( scope === IndexNode.INVOCATION_SUBGROUP ) {
propertyName = builder.getInvocationSubgroupIndex();
} else if ( scope === IndexNode.SUBGROUP ) {
propertyName = builder.getSubgroupIndex();
} else {
throw new Error( 'THREE.IndexNode: Unknown scope: ' + scope );
}
let output;
if ( builder.shaderStage === 'vertex' || builder.shaderStage === 'compute' ) {
output = propertyName;
} else {
const nodeVarying = varying( this );
output = nodeVarying.build( builder, nodeType );
}
return output;
}
}
IndexNode.VERTEX = 'vertex';
IndexNode.INSTANCE = 'instance';
IndexNode.SUBGROUP = 'subgroup';
IndexNode.INVOCATION_LOCAL = 'invocationLocal';
IndexNode.INVOCATION_SUBGROUP = 'invocationSubgroup';
IndexNode.DRAW = 'draw';
export default IndexNode;
/**
* TSL object that represents the index of a vertex within a mesh.
*
* @tsl
* @type {IndexNode}
*/
export const vertexIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.VERTEX );
/**
* TSL object that contextually represents specific index data depending on the shader stage.
*
* Within the vertex and fragment stages, `instanceIndex` will represent the index of the current mesh instance being evaluated by the shader.
* In these stages, use `instanceIndex` to modify a mesh based on its instance or to select per-instance data.
*
* ```js
* // instanceIndex will equal the current mesh's instance index between 0-500
* const material = new THREE.BasicNodeMaterial();
* material.positionNode = vec3( instanceIndex.mod( 10 ), instanceIndex.div( 10 ), 0 );
* const mesh = new THREE.InstancedMesh( geometry, material, 500 );
* ```
*
* Within the compute stage, `instanceIndex` will represent the global index of a compute invocation within the 3-dimensional compute workgroup load.
* In this stage, use `instanceIndex` to modify or select data at a given index within a buffer, or derive values from the index itself.
*
* ```js
* // instanceIndex will equal value between 0 - 255
* const computeFn = Fn() => {
*
* storageBuffer.element( instanceIndex ).assign( instanceIndex );
*
* } )().compute( 255 )
* ```
*
* @tsl
* @type {IndexNode}
*/
export const instanceIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.INSTANCE );
/**
* TSL object that represents the index of the subgroup the current compute invocation belongs to.
* Subgroup indices are local to the workgroups to which they belong.
*
* ```js
* // Execute 12 compute threads with a workgroup size of 9. Example assumes a subgroup size of 3.
* const computeFn = Fn( () => {
*
* storageBufferOne.element( instanceIndex ).assign( subgroupIndex );
* storageBufferTwo.element( instanceIndex ).assign( workgroupId.x );
*
* } )().compute( 12, [ 9 ] );
*
* // instanceIndex = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
* // Buffer One ( Subgroup Index ) = [ 0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0 ];
* // Buffer Two ( Workgroup ID ) = [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1 ];
* ```
*
* @tsl
* @type {IndexNode}
*/
export const subgroupIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.SUBGROUP );
/**
* TSL object that represents the index of a compute invocation within the scope of a subgroup.
*
* ```js
* // Execute 12 compute threads with a workgroup size of 12. Example assumes a subgroup size of 3.
* const computeFn = Fn( () => {
*
* storageBufferOne.element( instanceIndex ).assign( invocationSubgroupIndex );
* storageBufferTwo.element( instanceIndex ).assign( subgroupIndex );
*
* } )().compute( 12, [ 12 ] );
*
* // instanceIndex = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
* // Buffer One ( Invocation Subgroup Index ) = [ 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2 ];
* // Buffer Two ( Subgroup Index ) = [ 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3 ];
* ```
*
* @tsl
* @type {IndexNode}
*/
export const invocationSubgroupIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.INVOCATION_SUBGROUP );
/**
* TSL object that represents the index of a compute invocation within the scope of a workgroup.
*
* ```js
* // Execute 12 compute threads with a workgroup size of 4.
* const computeFn = Fn( () => {
*
* storageBufferOne.element( instanceIndex ).assign( invocationLocalIndex );
* storageBufferTwo.element( instanceIndex ).assign( workgroupId.x );
*
* } )().compute( 12, [ 4 ] );
*
* // instanceIndex = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
* // Buffer One ( Invocation Local Index ) = [ 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3 ];
* // Buffer Two ( Workgroup ID ) = [ 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2 ];
* ```
*
* @tsl
* @type {IndexNode}
*/
export const invocationLocalIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.INVOCATION_LOCAL );
/**
* TSL object that represents the index of a draw call.
*
* @tsl
* @type {IndexNode}
*/
export const drawIndex = /*@__PURE__*/ nodeImmutable( IndexNode, IndexNode.DRAW );