Merge pull request #20538 from AdaRoseCannon/curve-modifier

Examples: Added curve modifier examples

examples/jsm/misc/CurveModifier.d.ts

@@ -0,0 +1,50 @@
+import { Geometry, Material, Mesh, Spline } from '../../../build/three.module';
+import {
+	DataTexture,
+	Curve,
+	Uniform,
+	Material,
+	InstancedMesh
+} from '../../../src/Three';
+import { Flow } from './CurveModifier';
+import { modifyShader } from './CurveModifier';
+import { getUniforms } from './CurveModifier';
+import { updateSplineTexture } from './CurveModifier';
+import { initSplineTexture } from "./CurveModifier";
+
+interface SplineUniform {
+	spineTexture: Uniform,
+	pathOffset: Uniform,
+	pathSegment: Uniform,
+	spineOffset: Uniform,
+	Uniform,
+	flow: Uniform,
+}
+export function initSplineTexture(size?: number): DataTexture;
+
+export function updateSplineTexture(texture: DataTexture, splineCurve: Curve, offset?: number);
+
+export function getUniforms(splineTexture: DataTexture): SplineUniform;
+
+export function modifyShader(material: Material, uniforms: SplineUniform, numberOfCurves?: number);
+
+export class Flow {
+	constructor(mesh: Mesh, numberOfCurves?: number);
+	curveArray: number[];
+	curveLengthArray: number[];
+	object3D: Mesh;
+	splineTexure: DataTexture;
+	uniforms: SplineUniform;
+	updateCurve(index: number, curve: Curve);
+	moveAlongCurve(amount: number);
+}
+
+export class InstancedFlow extends Flow {
+	constructor(count:Number, curveCount:Number, geometry: Geometry, material: Material);
+	object3D: InstancedMesh;
+	offsets: number[];
+	whichCurve: number[];
+
+	moveIndividualAlongCurve(index: number, offset: number);
+	setCurve( index: number, curveNo: number )
+}

examples/jsm/misc/CurveModifier.js

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+// Original src: https://github.com/zz85/threejs-path-flow
+const BITS = 3;
+const TEXTURE_WIDTH = 1024;
+const TEXTURE_HEIGHT = 4;
+
+import {
+	DataTexture,
+	RGBFormat,
+	FloatType,
+	RepeatWrapping,
+	Mesh,
+	InstancedMesh,
+	NearestFilter,
+	DynamicDrawUsage,
+	Matrix4
+} from "../../../build/three.module.js";
+
+/**
+ * Make a new DataTexture to store the descriptions of the curves.
+ *
+ * @param { number } numberOfCurves the number of curves needed to be described by this texture.
+ */
+export function initSplineTexture( numberOfCurves = 1 ) {
+
+	const dataArray = new Float32Array( TEXTURE_WIDTH * TEXTURE_HEIGHT * numberOfCurves * BITS );
+	const dataTexture = new DataTexture(
+		dataArray,
+		TEXTURE_WIDTH,
+		TEXTURE_HEIGHT * numberOfCurves,
+		RGBFormat,
+		FloatType
+	);
+
+	dataTexture.wrapS = RepeatWrapping;
+	dataTexture.wrapY = RepeatWrapping;
+	dataTexture.magFilter = NearestFilter;
+	dataTexture.needsUpdate = true;
+
+	return dataTexture;
+
+}
+
+/**
+ * Write the curve description to the data texture
+ *
+ * @param { DataTexture } texture The DataTexture to write to
+ * @param { Curve } splineCurve The curve to describe
+ * @param { number } offset Which curve slot to write to
+ */
+export function updateSplineTexture( texture, splineCurve, offset = 0 ) {
+
+	const numberOfPoints = Math.floor( TEXTURE_WIDTH * ( TEXTURE_HEIGHT / 4 ) );
+	splineCurve.arcLengthDivisions = numberOfPoints / 2;
+	splineCurve.updateArcLengths();
+	const points = splineCurve.getSpacedPoints( numberOfPoints );
+	const frenetFrames = splineCurve.computeFrenetFrames( numberOfPoints, true );
+
+	for ( let i = 0; i < numberOfPoints; i ++ ) {
+
+		const rowOffset = Math.floor( i / TEXTURE_WIDTH );
+		const rowIndex = i % TEXTURE_WIDTH;
+
+		let pt = points[ i ];
+		setTextureValue( texture, rowIndex, pt.x, pt.y, pt.z, 0 + rowOffset + ( TEXTURE_HEIGHT * offset ) );
+		pt = frenetFrames.tangents[ i ];
+		setTextureValue( texture, rowIndex, pt.x, pt.y, pt.z, 1 + rowOffset + ( TEXTURE_HEIGHT * offset ) );
+		pt = frenetFrames.normals[ i ];
+		setTextureValue( texture, rowIndex, pt.x, pt.y, pt.z, 2 + rowOffset + ( TEXTURE_HEIGHT * offset ) );
+		pt = frenetFrames.binormals[ i ];
+		setTextureValue( texture, rowIndex, pt.x, pt.y, pt.z, 3 + rowOffset + ( TEXTURE_HEIGHT * offset ) );
+
+	}
+
+	texture.needsUpdate = true;
+
+}
+
+
+function setTextureValue( texture, index, x, y, z, o ) {
+
+	const image = texture.image;
+	const { data } = image;
+	const i = BITS * TEXTURE_WIDTH * o; // Row Offset
+	data[ index * BITS + i + 0 ] = x;
+	data[ index * BITS + i + 1 ] = y;
+	data[ index * BITS + i + 2 ] = z;
+
+}
+
+/**
+ * Create a new set of uniforms for describing the curve modifier
+ *
+ * @param { DataTexture } Texture which holds the curve description
+ */
+export function getUniforms( splineTexture ) {
+
+	const uniforms = {
+		spineTexture: { value: splineTexture },
+		pathOffset: { type: 'f', value: 0 }, // time of path curve
+		pathSegment: { type: 'f', value: 1 }, // fractional length of path
+		spineOffset: { type: 'f', value: 161 },
+		spineLength: { type: 'f', value: 400 },
+		flow: { type: 'i', value: 1 },
+	};
+	return uniforms;
+
+}
+
+export function modifyShader( material, uniforms, numberOfCurves = 1 ) {
+
+	if ( material.__ok ) return;
+	material.__ok = true;
+
+	material.onBeforeCompile = ( shader ) => {
+
+		if ( shader.__modified ) return;
+		shader.__modified = true;
+
+		Object.assign( shader.uniforms, uniforms );
+
+		const vertexShader = `
+		uniform sampler2D spineTexture;
+		uniform float pathOffset;
+		uniform float pathSegment;
+		uniform float spineOffset;
+		uniform float spineLength;
+		uniform int flow;
+
+		float textureLayers = ${TEXTURE_HEIGHT * numberOfCurves}.;
+		float textureStacks = ${TEXTURE_HEIGHT / 4}.;
+
+		${shader.vertexShader}
+		`.replace(
+		'#include <defaultnormal_vertex>',
+		`
+		vec4 worldPos = modelMatrix * vec4(position, 1.);
+
+		bool bend = flow > 0;
+		float xWeight = bend ? 0. : 1.;
+
+		#ifdef USE_INSTANCING
+		float pathOffsetFromInstanceMatrix = instanceMatrix[3][2];
+		float spineLengthFromInstanceMatrix = instanceMatrix[3][0];
+		float spinePortion = bend ? (worldPos.x + spineOffset) / spineLengthFromInstanceMatrix : 0.;
+		float mt = (spinePortion * pathSegment + pathOffset + pathOffsetFromInstanceMatrix)*textureStacks;
+		#else
+		float spinePortion = bend ? (worldPos.x + spineOffset) / spineLength : 0.;
+		float mt = (spinePortion * pathSegment + pathOffset)*textureStacks;
+		#endif
+
+		mt = mod(mt, textureStacks);
+		float rowOffset = floor(mt);
+
+		#ifdef USE_INSTANCING
+		rowOffset += instanceMatrix[3][1] * ${TEXTURE_HEIGHT}.;
+		#endif
+
+		vec3 spinePos = texture(spineTexture, vec2(mt, (0. + rowOffset + 0.5) / textureLayers)).xyz;
+		vec3 a =        texture(spineTexture, vec2(mt, (1. + rowOffset + 0.5) / textureLayers)).xyz;
+		vec3 b =        texture(spineTexture, vec2(mt, (2. + rowOffset + 0.5) / textureLayers)).xyz;
+		vec3 c =        texture(spineTexture, vec2(mt, (3. + rowOffset + 0.5) / textureLayers)).xyz;
+		mat3 basis = mat3(a, b, c);
+
+		vec3 transformed = basis
+			* vec3(worldPos.x * xWeight, worldPos.y * 1., worldPos.z * 1.)
+			+ spinePos;
+
+		vec3 transformedNormal = normalMatrix * (basis * objectNormal);
+		`
+	).replace(
+		'#include <begin_vertex>',
+		''
+	).replace(
+		'#include <project_vertex>',
+		`
+			vec4 mvPosition = viewMatrix * vec4( transformed, 1.0 );
+			// vec4 mvPosition = viewMatrix * worldPos;
+			gl_Position = projectionMatrix * mvPosition;
+			`
+	);
+
+		shader.vertexShader = vertexShader;
+
+	};
+
+}
+
+/**
+ * A helper class for making meshes bend aroudn curves
+ */
+export class Flow {
+
+	/**
+	 * @param {Mesh} mesh The mesh to clone and modify to bend around the curve
+	 * @param {number} numberOfCurves The amount of space that should preallocated for additional curves
+	 */
+	constructor( mesh, numberOfCurves = 1 ) {
+
+		const obj3D = mesh.clone();
+		const splineTexure = initSplineTexture( numberOfCurves );
+		const uniforms = getUniforms( splineTexure );
+		obj3D.traverse( function ( child ) {
+
+			if (
+				child instanceof Mesh ||
+				child instanceof InstancedMesh
+			) {
+
+				child.material = child.material.clone();
+				modifyShader( child.material, uniforms, numberOfCurves );
+
+			}
+
+		} );
+
+		this.curveArray = new Array( numberOfCurves );
+		this.curveLengthArray = new Array( numberOfCurves );
+
+		this.object3D = obj3D;
+		this.splineTexure = splineTexure;
+		this.uniforms = uniforms;
+
+	}
+
+	updateCurve( index, curve ) {
+
+		if ( index >= this.curveArray.length ) throw Error( 'Index out of range for Flow' );
+		const curveLength = curve.getLength();
+		this.uniforms.spineLength.value = curveLength;
+		this.curveLengthArray[ index ] = curveLength;
+		this.curveArray[ index ] = curve;
+		updateSplineTexture( this.splineTexure, curve, index );
+
+	}
+
+	moveAlongCurve( amount ) {
+
+		this.uniforms.pathOffset.value += amount;
+
+	}
+
+}
+const matrix = new Matrix4();
+
+/**
+ * A helper class for creating instanced versions of flow, where the instances are placed on the curve.
+ */
+export class InstancedFlow extends Flow {
+
+	/**
+	 *
+	 * @param {number} count The number of instanced elements
+	 * @param {number} curveCount The number of curves to preallocate for
+	 * @param {Geometry} geometry The geometry to use for the instanced mesh
+	 * @param {Material} material The material to use for the instanced mesh
+	 */
+	constructor( count, curveCount, geometry, material ) {
+
+		const mesh = new InstancedMesh(
+			geometry,
+			material,
+			count
+		);
+		mesh.instanceMatrix.setUsage( DynamicDrawUsage );
+		super( mesh, curveCount );
+
+		this.offsets = new Array( count ).fill( 0 );
+		this.whichCurve = new Array( count ).fill( 0 );
+
+	}
+
+	/**
+	 * The extra information about which curve and curve position is stored in the translation components of the matrix for the instanced objects
+	 * This writes that information to the matrix and marks it as needing update.
+	 *
+	 * @param {number} index of the instanced element to update
+	 */
+	writeChanges( index ) {
+
+		matrix.makeTranslation(
+			this.curveLengthArray[ this.whichCurve[ index ] ],
+			this.whichCurve[ index ],
+			this.offsets[ index ]
+		);
+		this.object3D.setMatrixAt( index, matrix );
+		this.object3D.instanceMatrix.needsUpdate = true;
+
+	}
+
+	/**
+	 * Move an individual element along the curve by a specific amount
+	 *
+	 * @param {number} index Which element to update
+	 * @param {number} offset Move by how much
+	 */
+	moveIndividualAlongCurve( index, offset ) {
+
+		this.offsets[ index ] += offset;
+		this.writeChanges( index );
+
+	}
+
+	/**
+	 * Select which curve to use for an element
+	 *
+	 * @param {number} index the index of the instanced element to update
+	 * @param {number} curveNo the index of the curve it should use
+	 */
+	setCurve( index, curveNo ) {
+
+		if ( isNaN( curveNo ) ) throw Error( "curve index being set is Not a Number (NaN)" );
+		this.whichCurve[ index ] = curveNo;
+		this.writeChanges( index );
+
+	}
+
+}