working box-sphere collision

fridek · Jun 13, 2011 · 046e4bd · 046e4bd
1 parent 8c91e7c
commit 046e4bd
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Showing 4 changed files with 16 additions and 26 deletions.
diff --git a/js/collision.js b/js/collision.js
@@ -34,12 +34,11 @@ function detectCollisionBoxSphere(box, sphere) {
         // sphere centre relative to box centre
         relCentre = M.subVec(sphere.position,box.position),
         // box size
-       // box_size = M.multiVec(box.scale,0.5),
         box_size = box.scale,
 
         collisionNormal, penetration, Vrn, restitution = 1, closestPtWorld, j, i;
 
-    // simple check if sphere is too far to possibly have any contact
+    // simple check if sphere is too far to possibly have any contact (SAT)
     if (Math.abs(relCentre[0]) - sphere.boundingSphereRadius > box_size[0] ||
         Math.abs(relCentre[1]) - sphere.boundingSphereRadius > box_size[1] ||
         Math.abs(relCentre[2]) - sphere.boundingSphereRadius > box_size[2] ) {
@@ -65,31 +64,17 @@ function detectCollisionBoxSphere(box, sphere) {
 
     closestPtWorld = M.addVec(closestPt,box.position);
 
-    collisionNormal = M.subVec(closestPtWorld, centre);
+    collisionNormal = M.subVec(centre, closestPtWorld);
     collisionNormal = M.vecNormalise(collisionNormal);
 
-/*
+    sphere.stepBack();
+
     Vrn = [];
     for(i=0;i<collisionNormal.length;i+=1) Vrn[i] = collisionNormal[i] * sphere.speed[i];
 
-//    i = M.multiVecVec(collisionNormal, collisionNormal);
-//    if(i != 0) {
-
     j = M.multiVec(Vrn,-(1+restitution));
 
-//    } else {
-//        j = 0;
-//    }
-    console.log('collision', Date.now(),
-            'col normal', collisionNormal,
-            'penetration', penetration,
-            'Vrn', Vrn,
-            'j', j,
-            'sphere speed', sphere.speed
-    );
-//    console.log(sphere.speed, M.multiVec(collisionNormal,j));
-
-    sphere.setMovement(M.subVec(sphere.speed, j));
-*/
+    sphere.setMovement(M.addVec(sphere.speed, j));
+
     return true;
 }
diff --git a/js/load.js b/js/load.js
@@ -1,11 +1,11 @@
 var settings = {
     gravity: [0.0,-1.0,0.0],
-    floorLevel: -10,
+    floorLevel: -15,
     floorBounce: 0.5
 };
 
 $(window).ready(function() {
-    var objects = generateSpheresCube(4,4,4,2,true);
+    var objects = generateSpheresCube(5,5,5,2,true);
     initScene(settings);
 
     for(var i = 0; i < objects.length; i+=1) {

diff --git a/js/object.js b/js/object.js
@@ -57,6 +57,11 @@ var makeObject = function (type, position, scale, boundingSphereRadius, id) {
             this.position = this.nextPosition;
         },
 
+        stepBack: function () {
+            this.nextPosition = this.prevPosition;
+            this.position = this.prevPosition;
+        },
+
         prevPosition: [0.0,0.0,0.0],
         position: position,
         nextPosition: [0.0,0.0,0.0],

diff --git a/js/utils.js b/js/utils.js
@@ -26,9 +26,9 @@ function generateSpheresCube(x,y,z,distance,random_movements) {
         k_end = 0.5 * z * distance,
         objects = [];
 
-    for(i = i_start; i <= i_end; i+=distance) {
-        for(j = j_start; j <= j_end; j+=distance) {
-            for(k = k_start; k <= k_end; k+=distance) {
+    for(i = i_start; i < i_end; i+=distance) {
+        for(j = j_start; j < j_end; j+=distance) {
+            for(k = k_start; k < k_end; k+=distance) {
             objects[cnt] = makeObject('sphere', [i,j,k], [0.5,0.5,0.5], null, "box" + cnt);
             if(random_movements) {
                 objects[cnt].setMovement([0.0,0.0,0.0], [Math.random()-0.5,Math.random()-0.5,Math.random()-0.5]);