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Refactor Frustum to use Plane (#6784)
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* Refactor Frustum to leverage Plane

* Make planes private

* Create Plane#normalize

* Refactor Frustum#setFromMat4

* Refactor Frustum#containsSphere

* Refactor setFromMat4 again

* Reorder Plane functions

* Add copy and clone for Frustum
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@willeastcott
willeastcott committed Jul 4, 2024
1 parent 13a05fd commit 351a919
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Showing 2 changed files with 107 additions and 94 deletions.
139 changes: 63 additions & 76 deletions src/core/shape/frustum.js
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
import { Plane } from './plane.js';

/**
* A frustum is a shape that defines the viewing space of a camera. It can be used to determine
* visibility of points and bounding spheres. Typically, you would not create a Frustum shape
Expand All @@ -6,6 +8,11 @@
* @category Math
*/
class Frustum {
/**
* The six planes that make up the frustum.
*
* @type {Plane[]}
*/
planes = [];

/**
Expand All @@ -15,8 +22,40 @@ class Frustum {
* const frustum = new pc.Frustum();
*/
constructor() {
for (let i = 0; i < 6; i++)
this.planes[i] = [];
for (let i = 0; i < 6; i++) {
this.planes[i] = new Plane();
}
}

/**
* Returns a clone of the specified frustum.
*
* @returns {Frustum} A duplicate frustum.
* @example
* const frustum = new pc.Frustum();
* const clone = frustum.clone();
*/
clone() {
/** @type {this} */
const cstr = this.constructor;
return new cstr().copy(this);
}

/**
* Copies the contents of a source frustum to a destination frustum.
*
* @param {Frustum} src - A source frustum to copy to the destination frustum.
* @returns {Frustum} Self for chaining.
* @example
* const src = entity.camera.frustum;
* const dst = new pc.Frustum();
* dst.copy(src);
*/
copy(src) {
for (let i = 0; i < 6; i++) {
this.planes[i].copy(src.planes[i]);
}
return this;
}

/**
Expand All @@ -26,74 +65,28 @@ class Frustum {
* frustum.
* @example
* // Create a perspective projection matrix
* const projMat = pc.Mat4();
* projMat.setPerspective(45, 16 / 9, 1, 1000);
* const projection = pc.Mat4();
* projection.setPerspective(45, 16 / 9, 1, 1000);
*
* // Create a frustum shape that is represented by the matrix
* const frustum = new pc.Frustum();
* frustum.setFromMat4(projMat);
* frustum.setFromMat4(projection);
*/
setFromMat4(matrix) {

const normalize = (plane) => {
const t = Math.sqrt(plane[0] * plane[0] + plane[1] * plane[1] + plane[2] * plane[2]);
const invT = 1 / t;
plane[0] *= invT;
plane[1] *= invT;
plane[2] *= invT;
plane[3] *= invT;
};

const vpm = matrix.data;
const [
m00, m01, m02, m03,
m10, m11, m12, m13,
m20, m21, m22, m23,
m30, m31, m32, m33
] = matrix.data;
const planes = this.planes;

// Extract the numbers for the RIGHT plane
let plane = planes[0];
plane[0] = vpm[3] - vpm[0];
plane[1] = vpm[7] - vpm[4];
plane[2] = vpm[11] - vpm[8];
plane[3] = vpm[15] - vpm[12];
normalize(plane);

// Extract the numbers for the LEFT plane
plane = planes[1];
plane[0] = vpm[3] + vpm[0];
plane[1] = vpm[7] + vpm[4];
plane[2] = vpm[11] + vpm[8];
plane[3] = vpm[15] + vpm[12];
normalize(plane);

// Extract the BOTTOM plane
plane = planes[2];
plane[0] = vpm[3] + vpm[1];
plane[1] = vpm[7] + vpm[5];
plane[2] = vpm[11] + vpm[9];
plane[3] = vpm[15] + vpm[13];
normalize(plane);

// Extract the TOP plane
plane = planes[3];
plane[0] = vpm[3] - vpm[1];
plane[1] = vpm[7] - vpm[5];
plane[2] = vpm[11] - vpm[9];
plane[3] = vpm[15] - vpm[13];
normalize(plane);

// Extract the FAR plane
plane = planes[4];
plane[0] = vpm[3] - vpm[2];
plane[1] = vpm[7] - vpm[6];
plane[2] = vpm[11] - vpm[10];
plane[3] = vpm[15] - vpm[14];
normalize(plane);

// Extract the NEAR plane
plane = planes[5];
plane[0] = vpm[3] + vpm[2];
plane[1] = vpm[7] + vpm[6];
plane[2] = vpm[11] + vpm[10];
plane[3] = vpm[15] + vpm[14];
normalize(plane);
planes[0].set(m03 - m00, m13 - m10, m23 - m20, m33 - m30).normalize(); // RIGHT
planes[1].set(m03 + m00, m13 + m10, m23 + m20, m33 + m30).normalize(); // LEFT
planes[2].set(m03 + m01, m13 + m11, m23 + m21, m33 + m31).normalize(); // BOTTOM
planes[3].set(m03 - m01, m13 - m11, m23 - m21, m33 - m31).normalize(); // TOP
planes[4].set(m03 - m02, m13 - m12, m23 - m22, m33 - m32).normalize(); // FAR
planes[5].set(m03 + m02, m13 + m12, m23 + m22, m33 + m32).normalize(); // NEAR
}

/**
Expand All @@ -105,8 +98,8 @@ class Frustum {
*/
containsPoint(point) {
for (let p = 0; p < 6; p++) {
const plane = this.planes[p];
if (plane[0] * point.x + plane[1] * point.y + plane[2] * point.z + plane[3] <= 0) {
const { normal, distance } = this.planes[p];
if (normal.dot(point) + distance <= 0) {
return false;
}
}
Expand All @@ -124,21 +117,15 @@ class Frustum {
* frustum and 2 if it is contained by the frustum.
*/
containsSphere(sphere) {

const sr = sphere.radius;
const sc = sphere.center;
const scx = sc.x;
const scy = sc.y;
const scz = sc.z;
const planes = this.planes;
const { center, radius } = sphere;

let c = 0;
for (let p = 0; p < 6; p++) {
const plane = planes[p];
const d = plane[0] * scx + plane[1] * scy + plane[2] * scz + plane[3];
if (d <= -sr)
const { normal, distance } = this.planes[p];
const d = normal.dot(center) + distance;
if (d <= -radius)
return 0;
if (d > sr)
if (d > radius)
c++;
}

Expand Down
62 changes: 44 additions & 18 deletions src/core/shape/plane.js
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,6 @@ class Plane {
* The normal of the plane.
*
* @type {Vec3}
* @readonly
*/
normal = new Vec3();

Expand All @@ -36,15 +35,25 @@ class Plane {
}

/**
* Sets the plane based on a specified normal and a point on the plane.
* Returns a clone of the specified plane.
*
* @param {Vec3} point - The point on the plane.
* @param {Vec3} normal - The normal of the plane.
* @returns {this} A duplicate plane.
*/
clone() {
/** @type {this} */
const cstr = this.constructor;
return new cstr().copy(this);
}

/**
* Copies the contents of a source plane to a destination plane.
*
* @param {Plane} src - A source plane to copy to the destination plane.
* @returns {Plane} Self for chaining.
*/
setFromPointNormal(point, normal) {
this.normal.copy(normal);
this.distance = -this.normal.dot(point);
copy(src) {
this.normal.copy(src.normal);
this.distance = src.distance;
return this;
}

Expand Down Expand Up @@ -92,26 +101,43 @@ class Plane {
}

/**
* Copies the contents of a source Plane.
* Normalize the normal of the plane.
*
* @param {Plane} src - The Plane to copy from.
* @returns {Plane} Self for chaining.
*/
copy(src) {
this.normal.copy(src.normal);
this.distance = src.distance;
normalize() {
const invLength = 1 / this.normal.length();
this.normal.mulScalar(invLength);
this.distance *= invLength;
return this;
}

/**
* Returns a clone of the Plane.
* Sets the plane based on a normal and a distance from the origin.
*
* @returns {this} A duplicate Plane.
* @param {number} nx - The x-component of the normal.
* @param {number} ny - The y-component of the normal.
* @param {number} nz - The z-component of the normal.
* @param {number} d - The distance from the origin.
* @returns {Plane} Self for chaining.
*/
clone() {
/** @type {this} */
const cstr = this.constructor;
return new cstr().copy(this);
set(nx, ny, nz, d) {
this.normal.set(nx, ny, nz);
this.distance = d;
return this;
}

/**
* Sets the plane based on a specified normal and a point on the plane.
*
* @param {Vec3} point - The point on the plane.
* @param {Vec3} normal - The normal of the plane.
* @returns {Plane} Self for chaining.
*/
setFromPointNormal(point, normal) {
this.normal.copy(normal);
this.distance = -this.normal.dot(point);
return this;
}
}

Expand Down

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