You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
325 lines
8.9 KiB
325 lines
8.9 KiB
// Original src: https://github.com/zz85/threejs-path-flow
|
|
const CHANNELS = 4;
|
|
const TEXTURE_WIDTH = 1024;
|
|
const TEXTURE_HEIGHT = 4;
|
|
|
|
import {
|
|
DataTexture,
|
|
RGBAFormat,
|
|
FloatType,
|
|
RepeatWrapping,
|
|
Mesh,
|
|
InstancedMesh,
|
|
NearestFilter,
|
|
DynamicDrawUsage,
|
|
Matrix4
|
|
} from 'three';
|
|
|
|
/**
|
|
* 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 * CHANNELS );
|
|
const dataTexture = new DataTexture(
|
|
dataArray,
|
|
TEXTURE_WIDTH,
|
|
TEXTURE_HEIGHT * numberOfCurves,
|
|
RGBAFormat,
|
|
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 = CHANNELS * TEXTURE_WIDTH * o; // Row Offset
|
|
data[ index * CHANNELS + i + 0 ] = x;
|
|
data[ index * CHANNELS + i + 1 ] = y;
|
|
data[ index * CHANNELS + i + 2 ] = z;
|
|
data[ index * CHANNELS + i + 3 ] = 1;
|
|
|
|
}
|
|
|
|
/**
|
|
* 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}
|
|
`
|
|
// chunk import moved in front of modified shader below
|
|
.replace( '#include <beginnormal_vertex>', '' )
|
|
|
|
// vec3 transformedNormal declaration overriden below
|
|
.replace( '#include <defaultnormal_vertex>', '' )
|
|
|
|
// vec3 transformed declaration overriden below
|
|
.replace( '#include <begin_vertex>', '' )
|
|
|
|
// shader override
|
|
.replace(
|
|
/void\s*main\s*\(\)\s*\{/,
|
|
`
|
|
void main() {
|
|
#include <beginnormal_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 = texture2D(spineTexture, vec2(mt, (0. + rowOffset + 0.5) / textureLayers)).xyz;
|
|
vec3 a = texture2D(spineTexture, vec2(mt, (1. + rowOffset + 0.5) / textureLayers)).xyz;
|
|
vec3 b = texture2D(spineTexture, vec2(mt, (2. + rowOffset + 0.5) / textureLayers)).xyz;
|
|
vec3 c = texture2D(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 <project_vertex>',
|
|
`vec4 mvPosition = modelViewMatrix * vec4( transformed, 1.0 );
|
|
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 );
|
|
|
|
}
|
|
|
|
}
|
|
|