Merge pull request #83 from pmndrs/triggers

feat(body): add isTrigger option
pmndrs · Mar 6, 2021 · e7c57b6 · e7c57b6
2 parents db058cb + de322f9
commit e7c57b6
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Showing 7 changed files with 90 additions and 6 deletions.
diff --git a/examples/js/Demo.js b/examples/js/Demo.js
@@ -547,6 +547,7 @@ class Demo extends CANNON.EventTarget {
     this.currentMaterial = this.solidMaterial
     const contactDotMaterial = new THREE.MeshBasicMaterial({ color: 0xffffff })
     this.particleMaterial = new THREE.MeshLambertMaterial({ color: 0xff0000 })
+    this.triggerMaterial = new THREE.MeshBasicMaterial({ color: 0x00ff00, wireframe: true })
 
     const contactPointGeometry = new THREE.SphereGeometry(0.1, 6, 6)
     this.contactMeshCache = new GeometryCache(this.scene, () => {
@@ -894,10 +895,9 @@ class Demo extends CANNON.EventTarget {
       throw new Error('The argument passed to addVisual() is not a body')
     }
 
-    // if it's a particle paint it red, otherwise just gray
-    const material = body.shapes.every((s) => s instanceof CANNON.Particle)
-      ? this.particleMaterial
-      : this.currentMaterial
+    // if it's a particle paint it red, if it's a trigger paint it as green, otherwise just gray
+    const isParticle = body.shapes.every((s) => s instanceof CANNON.Particle)
+    const material = isParticle ? this.particleMaterial : body.isTrigger ? this.triggerMaterial : this.currentMaterial
 
     // get the correspondant three.js mesh
     const mesh = bodyToMesh(body, material)

diff --git a/examples/trigger.html b/examples/trigger.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>cannon.js - trigger demo</title>
+    <link rel="stylesheet" href="css/style.css" type="text/css" />
+    <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0" />
+  </head>
+  <body>
+    <script type="module">
+      import * as CANNON from '../dist/cannon-es.js'
+      import { Demo } from './js/Demo.js'
+
+      /**
+       * Demonstrates the use of trigger bodies, bodies which don't
+       * collide with other bodies and allow you to run callbacks
+       * when another body enters/exits them.
+       */
+      const demo = new Demo()
+
+      demo.addScene('Trigger', () => {
+        const world = setupWorld(demo)
+
+        const radius = 1
+
+        // Sphere moving towards right
+        const sphereShape = new CANNON.Sphere(radius)
+        const sphereBody = new CANNON.Body({ mass: 1 })
+        sphereBody.addShape(sphereShape)
+        sphereBody.position.set(-5, 0, 0)
+        const impulse = new CANNON.Vec3(5.5, 0, 0)
+        const topPoint = new CANNON.Vec3(0, radius, 0)
+        sphereBody.applyImpulse(impulse, topPoint)
+        sphereBody.linearDamping = 0.3
+        sphereBody.angularDamping = 0.3
+        world.addBody(sphereBody)
+        demo.addVisual(sphereBody)
+
+        // Trigger body
+        const boxShape = new CANNON.Box(new CANNON.Vec3(2, 2, 5))
+        const triggerBody = new CANNON.Body({ isTrigger: true })
+        triggerBody.addShape(boxShape)
+        triggerBody.position.set(5, radius, 0)
+        world.addBody(triggerBody)
+        demo.addVisual(triggerBody)
+
+        // It is possible to run code on the exit/enter
+        // of the trigger.
+        triggerBody.addEventListener('collide', (event) => {
+          if (event.body === sphereBody) {
+            console.log('The sphere entered the trigger!', event)
+          }
+        })
+        world.addEventListener('endContact', (event) => {
+          if (
+            (event.bodyA === sphereBody && event.bodyB === triggerBody) ||
+            (event.bodyB === sphereBody && event.bodyA === triggerBody)
+          ) {
+            console.log('The sphere exited the trigger!', event)
+          }
+        })
+      })
+
+      demo.start()
+
+      function setupWorld(demo) {
+        const world = demo.getWorld()
+        world.gravity.set(0, 0, 0) // no gravity
+
+        return world
+      }
+    </script>
+  </body>
+</html>
diff --git a/index.html b/index.html
@@ -153,6 +153,7 @@
         'spring',
         'stacks',
         'tear',
+        'trigger',
         'trimesh',
         'tween',
       ]

diff --git a/readme.md b/readme.md
@@ -6,13 +6,14 @@ It's a type-safe flatbundle (esm and cjs) which allows for **tree shaking** and
 
 These minor changes and improvements were also made:
 
-- These PRs from the original repo were merged: [schteppe/cannon.js#433](https://github.com/schteppe/cannon.js/pull/433), [schteppe/cannon.js#430](https://github.com/schteppe/cannon.js/pull/430), [schteppe/cannon.js#418](https://github.com/schteppe/cannon.js/pull/418), [schteppe/cannon.js#360](https://github.com/schteppe/cannon.js/pull/360), [schteppe/cannon.js#265](https://github.com/schteppe/cannon.js/pull/265), [schteppe/cannon.js#392](https://github.com/schteppe/cannon.js/pull/392)
+- These PRs from the original repo were merged: [schteppe/cannon.js#433](https://github.com/schteppe/cannon.js/pull/433), [schteppe/cannon.js#430](https://github.com/schteppe/cannon.js/pull/430), [schteppe/cannon.js#418](https://github.com/schteppe/cannon.js/pull/418), [schteppe/cannon.js#360](https://github.com/schteppe/cannon.js/pull/360), [schteppe/cannon.js#265](https://github.com/schteppe/cannon.js/pull/265), [schteppe/cannon.js#392](https://github.com/schteppe/cannon.js/pull/392), [schteppe/cannon.js#424](https://github.com/schteppe/cannon.js/pull/424)
 - The `ConvexPolyhedron` constructor now accepts an object instead of a list of arguments. [#6](https://github.com/pmndrs/cannon-es/pull/6)
 - The `Cylinder` is now oriented on the Y axis. [#30](https://github.com/pmndrs/cannon-es/pull/30)
 - The `type` property of the `Cylinder` is now equal to `Shape.types.CYLINDER`. [#59](https://github.com/pmndrs/cannon-es/pull/59)
 - `Body.applyImpulse()` and `Body.applyForce()` are now relative to the center of the body instead of the center of the world [86b0444](https://github.com/schteppe/cannon.js/commit/86b0444c93356aeaa25dd1af795fa162574c6f4b)
 - Sleeping bodies now wake up if a force or an impulse is applied to them [#61](https://github.com/pmndrs/cannon-es/pull/61)
 - Added a property `World.hasActiveBodies: boolean` which will be false when all physics bodies are sleeping. This allows for invalidating frames when physics aren't active for increased performance.
+- Add support for [Trigger bodies](https://pmndrs.github.io/cannon-es/examples/trigger). [#83](https://github.com/pmndrs/cannon-es/pull/83)
 - Deprecated properties and methods have been removed.
 - The [original cannon.js debugger](https://github.com/schteppe/cannon.js/blob/master/tools/threejs/CannonDebugRenderer.js), which shows the wireframes of each body, has been moved to its own repo [cannon-es-debugger](https://github.com/pmndrs/cannon-es-debugger).
 

diff --git a/screenshots/trigger.png b/screenshots/trigger.png
diff --git a/src/objects/Body.ts b/src/objects/Body.ts
@@ -44,6 +44,7 @@ export type BodyOptions = {
   linearFactor?: Vec3
   angularFactor?: Vec3
   shape?: Shape
+  isTrigger?: boolean
 }
 
 /**
@@ -130,6 +131,12 @@ export class Body extends EventTarget {
   aabbNeedsUpdate: boolean // Indicates if the AABB needs to be updated before use.
   boundingRadius: number // Total bounding radius of the Body including its shapes, relative to body.position.
   wlambda: Vec3
+  /**
+   * When true the body behaves like a trigger. It does not collide
+   * with other bodies but collision events are still triggered.
+   * @default false
+   */
+  isTrigger: boolean
 
   static idCounter: number
   static COLLIDE_EVENT_NAME: 'collide'
@@ -246,6 +253,7 @@ export class Body extends EventTarget {
     this.aabbNeedsUpdate = true
     this.boundingRadius = 0
     this.wlambda = new Vec3()
+    this.isTrigger = Boolean(options.isTrigger)
 
     if (options.shape) {
       this.addShape(options.shape)

diff --git a/src/solver/Solver.ts b/src/solver/Solver.ts
@@ -34,7 +34,7 @@ export class Solver {
    * @param {Equation} eq
    */
   addEquation(eq: Equation): void {
-    if (eq.enabled) {
+    if (eq.enabled && !eq.bi.isTrigger && !eq.bj.isTrigger) {
       this.equations.push(eq)
     }
   }