BoxGeometry constructor
BoxGeometry([
- dynamic width = 1,
- dynamic height = 1,
- dynamic depth = 1,
- dynamic widthSegments = 1,
- dynamic heightSegments = 1,
- dynamic depthSegments = 1,
Implementation
BoxGeometry(
[width = 1,
height = 1,
depth = 1,
widthSegments = 1,
heightSegments = 1,
depthSegments = 1])
: super() {
parameters = {
"width": width,
"height": height,
"depth": depth,
"widthSegments": widthSegments,
"heightSegments": heightSegments,
"depthSegments": depthSegments
};
// segments
int _widthSegments = Math.floor(widthSegments);
int _heightSegments = Math.floor(heightSegments);
int _depthSegments = Math.floor(depthSegments);
// buffers
List<num> indices = [];
List<double> vertices = [];
List<double> normals = [];
List<double> uvs = [];
// helper variables
numberOfVertices = 0;
groupStart = 0;
void buildPlane(String u, String v, String w, double udir, double vdir, width,
height, depth, gridX, gridY, materialIndex) {
var segmentWidth = width / gridX;
var segmentHeight = height / gridY;
var widthHalf = width / 2;
var heightHalf = height / 2;
var depthHalf = depth / 2;
var gridX1 = gridX + 1;
var gridY1 = gridY + 1;
var vertexCounter = 0;
var groupCount = 0;
var vector = Vector3();
// generate vertices, normals and uvs
// print("buildPlane: u: ${u} v: ${v} w: ${w} udir: ${udir} vdir: ${vdir} width: ${width} height: ${height} depth: ${depth} gridX: ${gridX} gridY: ${gridY} materialIndex: ${materialIndex} ");
for (var iy = 0; iy < gridY1; iy++) {
var y = iy * segmentHeight - heightHalf;
for (var ix = 0; ix < gridX1; ix++) {
var x = ix * segmentWidth - widthHalf;
// print("iy: ${iy} ix: ${ix} y: ${y} x: ${x} depthHalf: ${depthHalf} ");
// set values to correct vector component
// vector[ u ] = x * udir;
// vector[ v ] = y * vdir;
// vector[ w ] = depthHalf;
vector.setP(u, x * udir);
vector.setP(v, y * vdir);
vector.setP(w, depthHalf);
// now apply vector to vertex buffer
vertices.addAll(
[vector.x.toDouble(), vector.y.toDouble(), vector.z.toDouble()]);
// set values to correct vector component
// vector[ u ] = 0;
// vector[ v ] = 0;
// vector[ w ] = depth > 0 ? 1 : - 1;
vector.setP(u, 0);
vector.setP(v, 0);
vector.setP(w, depth > 0 ? 1 : -1);
// now apply vector to normal buffer
normals.addAll(
[vector.x.toDouble(), vector.y.toDouble(), vector.z.toDouble()]);
// uvs
uvs.add(ix / gridX);
uvs.add(1 - (iy / gridY));
// counters
vertexCounter += 1;
}
}
// indices
// 1. you need three indices to draw a single face
// 2. a single segment consists of two faces
// 3. so we need to generate six (2*3) indices per segment
for (var iy = 0; iy < gridY; iy++) {
for (var ix = 0; ix < gridX; ix++) {
var a = numberOfVertices + ix + gridX1 * iy;
var b = numberOfVertices + ix + gridX1 * (iy + 1);
var c = numberOfVertices + (ix + 1) + gridX1 * (iy + 1);
var d = numberOfVertices + (ix + 1) + gridX1 * iy;
// faces
indices.addAll([a, b, d]);
indices.addAll([b, c, d]);
// increase counter
groupCount += 6;
}
}
// add a group to the geometry. this will ensure multi material support
addGroup(groupStart, groupCount, materialIndex);
// calculate new start value for groups
groupStart += groupCount;
// update total number of vertices
numberOfVertices += vertexCounter;
}
// build each side of the box geometry
buildPlane('z', 'y', 'x', -1, -1, depth, height, width, _depthSegments,
_heightSegments, 0); // px
buildPlane('z', 'y', 'x', 1, -1, depth, height, -width, _depthSegments,
_heightSegments, 1); // nx
buildPlane('x', 'z', 'y', 1, 1, width, depth, height, _widthSegments,
_depthSegments, 2); // py
buildPlane('x', 'z', 'y', 1, -1, width, depth, -height, _widthSegments,
_depthSegments, 3); // ny
buildPlane('x', 'y', 'z', 1, -1, width, height, depth, _widthSegments,
_heightSegments, 4); // pz
buildPlane('x', 'y', 'z', -1, -1, width, height, -depth, _widthSegments,
_heightSegments, 5); // nz
// build geometry
setIndex(indices);
setAttribute('position',
Float32BufferAttribute(Float32Array.from(vertices), 3, false));
setAttribute('normal',
Float32BufferAttribute(Float32Array.from(normals), 3, false));
setAttribute(
'uv', Float32BufferAttribute(Float32Array.from(uvs), 2, false));
}