@giro3d/giro3d
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A JS/WebGL framework for 3D geospatial data visualization
194 lines (190 loc) • 6.83 kB
JavaScript
import { Box3, Float32BufferAttribute, Int16BufferAttribute, Int32BufferAttribute, Int8BufferAttribute, IntType, Uint16BufferAttribute, Uint32BufferAttribute, Uint8BufferAttribute, Vector3 } from 'three';
import TypedArrayVector from '../../core/TypedArrayVector';
import { Vector3Array } from '../../core/VectorArray';
import { UnsupportedAttributeError } from '../../entities/PointCloud';
import { evaluateFilters } from './filter';
/**
* Reads the color in the provided LAS view.
*
* Note: the color is the aggregate of the `Red`, `Green` and `Blue` dimensions.
*
* @param view - The view to read.
* @param stride - The stride (take every Nth point). A stride of 3 means we take every 3rd point
* and discard the others.
* @param compress - Compress colors to 8-bit.
* @param filters - The optional dimension filters to use.
* @returns An object containing the color buffer.
*/
export function readColor(view, stride, compress, filters) {
const pointCount = view.pointCount;
const [readR, readG, readB] = ['Red', 'Green', 'Blue'].map(view.getter);
const array = new Vector3Array(compress ? new Uint8Array(pointCount * 3) : new Uint16Array(pointCount * 3));
array.length = 0;
const factor = compress ? 1 / 65536 * 256 : 1;
for (let i = 0; i < pointCount; i += stride) {
if (evaluateFilters(filters, i)) {
const r = readR(i) * factor;
const g = readG(i) * factor;
const b = readB(i) * factor;
array.push(r, g, b);
}
}
return array.array.buffer;
}
/**
* Reads the point position in the provided LAS view.
* @param view - The view to read.
* @param origin - The origin to use for relative point coordinates.
* @param stride - The stride (take every Nth point). A stride of 3 means we take every 3rd point
* and discard the others.
* @param filters - The optional dimension filters to use.
* @returns An object containing the relative position buffer, and a local (tight) bounding box of
* the position buffer.
*/
export function readPosition(view, origin, stride, filters) {
const pointCount = view.pointCount;
const [readX, readY, readZ] = ['X', 'Y', 'Z'].map(view.getter);
const pointCountIncludingStride = Math.floor(pointCount / stride) + pointCount % stride;
const array = new Vector3Array(new Float32Array(pointCountIncludingStride * 3));
array.length = 0;
let minx = +Infinity;
let miny = +Infinity;
let minz = +Infinity;
let maxx = -Infinity;
let maxy = -Infinity;
let maxz = -Infinity;
for (let i = 0; i < pointCount; i += stride) {
if (evaluateFilters(filters, i)) {
const x = readX(i) - origin.x;
const y = readY(i) - origin.y;
const z = readZ(i) - origin.z;
minx = Math.min(x, minx);
miny = Math.min(y, miny);
minz = Math.min(z, minz);
maxx = Math.max(x, maxx);
maxy = Math.max(y, maxy);
maxz = Math.max(z, maxz);
array.push(x, y, z);
}
}
array.trim();
return {
buffer: array.array.buffer,
localBoundingBox: new Box3(new Vector3(minx, miny, minz), new Vector3(maxx, maxy, maxz))
};
}
function fillBuffer(get, pointCount, stride, buffer, filters) {
for (let i = 0; i < pointCount; i += stride) {
if (evaluateFilters(filters, i)) {
buffer.push(get(i));
}
}
}
export function readScalarAttribute(view, attribute, stride, filters) {
const dimension = attribute.name;
let readFn;
switch (attribute.type) {
case 'float':
readFn = read(Float32Array);
break;
case 'signed':
switch (attribute.size) {
case 1:
readFn = read(Int8Array);
break;
case 2:
readFn = read(Int16Array);
break;
case 4:
readFn = read(Int32Array);
break;
default:
throw new Error('invalid attribute size for signed values: ' + attribute.size);
}
break;
case 'unsigned':
switch (attribute.size) {
case 1:
readFn = read(Uint8Array);
break;
case 2:
readFn = read(Uint16Array);
break;
case 4:
readFn = read(Uint32Array);
break;
default:
throw new Error('invalid attribute size for unsigned values: ' + attribute.size);
}
break;
default:
throw new UnsupportedAttributeError(dimension);
}
return readFn(dimension, view, stride, filters);
}
export function createBufferAttribute(buffer, attribute, compressColors) {
const dimension = attribute.name;
// Special case for colors, since they can be either 8-bit or 16-bit
// depending on the user's choice. Note that since they are normalized in both cases,
// the shader will handle both cases the same way. The only (potential) difference is
// for very high dynamic range colors, the 16-bit case might reduce banding and other
// similar artifacts. However, in 99% using a 8-bit color buffer is enough.
if (attribute.interpretation === 'color') {
return compressColors ? new Uint8BufferAttribute(buffer, 3, true) : new Uint16BufferAttribute(buffer, 3, true);
}
switch (attribute.type) {
case 'float':
return new Float32BufferAttribute(buffer, attribute.dimension);
case 'signed':
{
let result;
switch (attribute.size) {
case 1:
result = new Int8BufferAttribute(buffer, attribute.dimension);
break;
case 2:
result = new Int16BufferAttribute(buffer, attribute.dimension);
break;
case 4:
result = new Int32BufferAttribute(buffer, attribute.dimension);
break;
default:
throw new Error('invalid attribute size for signed values: ' + attribute.size);
}
result.gpuType = IntType;
return result;
}
case 'unsigned':
{
let result;
switch (attribute.size) {
case 1:
result = new Uint8BufferAttribute(buffer, attribute.dimension);
break;
case 2:
result = new Uint16BufferAttribute(buffer, attribute.dimension);
break;
case 4:
result = new Uint32BufferAttribute(buffer, attribute.dimension);
break;
default:
throw new Error('invalid attribute size for unsigned values: ' + attribute.size);
}
result.gpuType = IntType;
return result;
}
default:
throw new UnsupportedAttributeError(dimension);
}
}
/**
* Reads an attribute from the view.
*/
function read(ctor) {
return (dimension, view, stride, filters) => {
const pointCount = view.pointCount;
const array = new TypedArrayVector(pointCount, cap => new ctor(cap));
fillBuffer(view.getter(dimension), pointCount, stride, array, filters);
return array.getArray().buffer;
};
}