initial physics constraints

scripts/base.js

@@ -1245,6 +1245,7 @@ Object.defineProperty(Number.prototype, 'lerp', {
 Math.clamp = function (x, l, h) { return x > h ? h : x < l ? l : x; }
 
 Math.random_range = function(min,max) { return Math.random() * (max-min) + min; };
+Math.rand_int = function(max) { return Math.floor(Math.random()*max); };
 
 Math.snap = function(val, grid) {
   if (!grid || grid === 1) return Math.round(val);

scripts/entity.js

@@ -193,6 +193,19 @@ var gameobject = {
   full_path() {
     return this.path_from(Primum);
   },
+  /* pin this object to the to object */
+  pin(to) {
+    var p = cmd(222,this.body, to.body);
+  },
+  pivot(to, piv) {
+    piv ??= this.worldpos();
+    var p = cmd(221,this.body,to.body,piv);
+  },
+  gear(to, phase, ratio) {
+    phase ??= 1;
+    ratio ??= 1;
+    var p = cmd(223,this.body,to.body,phase,ratio);
+  },
   
     path_from(o) {
       var p = this.toString();
@@ -517,6 +530,7 @@ var gameobject = {
     Player.do_uncontrol(this);
     Register.unregister_obj(this);
     
+    if (this.__proto__.instances)
       this.__proto__.instances.remove(this);
 
     for (var key in this.components) {

source/engine/2dphysics.c

@@ -213,10 +213,9 @@ struct phys2d_circle *Make2DCircle(gameobject *go) {
   return new;
 }
 
-float phys2d_circle_moi(struct phys2d_circle *c, float m) {
+float phys2d_circle_moi(struct phys2d_circle *c) {
-  return 1;
+  float m = c->shape.go->mass;
-  //TODO: Calculate correctly
+  return cpMomentForCircle(m, 0, cpCircleShapeGetRadius(c->shape.shape), cpCircleShapeGetOffset(c->shape.shape));
-  //return cpMomentForCircle(m, 0, c->radius, c->offset);
 }
 
 void phys2d_circledel(struct phys2d_circle *c) {
@@ -233,6 +232,18 @@ void phys2d_dbgdrawcpcirc(cpShape *c) {
   draw_circle(pos,radius,radius,color,-1);
 }
 
+void phys2d_shape_apply(struct phys2d_shape *s)
+{
+  float moment = cpBodyGetMoment(s->go->body);
+  float moi = s->moi(s->data);
+
+  s->apply(s->data);
+  float newmoi = s->moi(s->data);
+  moment-=moi;
+  moment += newmoi;
+  cpBodySetMoment(s->go->body, moment);
+}
+
 void phys2d_dbgdrawcircle(struct phys2d_circle *circle) {
   phys2d_dbgdrawcpcirc(circle->shape.shape);
 }
@@ -268,12 +279,16 @@ void phys2d_poly_free(struct phys2d_poly *poly)
   free(poly);
 }
 
-float phys2d_poly_moi(struct phys2d_poly *poly, float m) {
+float phys2d_poly_moi(struct phys2d_poly *poly) {
-  float moi = cpMomentForPoly(m, arrlen(poly->points), (cpVect*)poly->points, cpvzero, poly->radius);
+  float m = poly->shape.go->mass;
-  if (isnan(moi)) {
+  int len = cpPolyShapeGetCount(poly->shape.shape);
-//    YughError("Polygon MOI returned an error. Returning 0.");
+  cpVect points[len];
+  for (int i = 0; i < len; i++)
+    points[i] = cpPolyShapeGetVert(poly->shape.shape, i);
+
+  float moi = cpMomentForPoly(m, len, points, cpvzero, poly->radius);
+  if (!isfinite(moi))
     return 0;
-  }
 
   return moi;
 }
@@ -297,7 +312,7 @@ void phys2d_poly_setverts(struct phys2d_poly *poly, HMM_Vec2 *verts) {
   for (int i = 0; i < arrlen(verts); i++)
     poly->points[i] = verts[i];
 
-  phys2d_applypoly(poly);
+  phys2d_shape_apply(&poly->shape);
 }
 
 void phys2d_applypoly(struct phys2d_poly *poly) {
@@ -365,7 +380,8 @@ void phys2d_edge_free(struct phys2d_edge *edge)
   free(edge);
 }
 
-float phys2d_edge_moi(struct phys2d_edge *edge, float m) {
+float phys2d_edge_moi(struct phys2d_edge *edge) {
+  float m = edge->shape.go->mass;
   float moi = 0;
   for (int i = 0; i < arrlen(edge->points) - 1; i++)
     moi += cpMomentForSegment(m, edge->points[i].cp, edge->points[i + 1].cp, edge->thickness);

source/engine/2dphysics.h

@@ -23,11 +23,13 @@ struct phys2d_shape {
   gameobject *go;
   void *data; /* The specific subtype; phys2d_circle, etc */
   void (*debugdraw)(void *data);
-  float (*moi)(void *data, float mass);
+  float (*moi)(void *data);
   void (*apply)(void *data);
   void (*free)(void *data);
 };
 
+void phys2d_shape_apply(struct phys2d_shape *s);
+
 /* Circles are the fastest colldier type */
 struct phys2d_circle {
   float radius;
@@ -56,7 +58,7 @@ struct phys2d_circle *Make2DCircle(gameobject *go);
 void phys2d_circledel(struct phys2d_circle *c);
 void phys2d_applycircle(struct phys2d_circle *circle);
 void phys2d_dbgdrawcircle(struct phys2d_circle *circle);
-float phys2d_circle_moi(struct phys2d_circle *c, float m);
+float phys2d_circle_moi(struct phys2d_circle *c);
 
 struct phys2d_poly *Make2DPoly(gameobject *go);
 void phys2d_poly_free(struct phys2d_poly *poly);
@@ -65,7 +67,7 @@ void phys2d_applypoly(struct phys2d_poly *poly);
 void phys2d_dbgdrawpoly(struct phys2d_poly *poly);
 void phys2d_polyaddvert(struct phys2d_poly *poly);
 void phys2d_poly_setverts(struct phys2d_poly *poly, HMM_Vec2 *verts);
-float phys2d_poly_moi(struct phys2d_poly *poly, float m);
+float phys2d_poly_moi(struct phys2d_poly *poly);
 
 struct phys2d_edge *Make2DEdge(gameobject *go);
 void phys2d_edge_free(struct phys2d_edge *edge);
@@ -74,7 +76,7 @@ void phys2d_applyedge(struct phys2d_edge *edge);
 void phys2d_dbgdrawedge(struct phys2d_edge *edge);
 void phys2d_edgeaddvert(struct phys2d_edge *edge, HMM_Vec2 v);
 void phys2d_edge_rmvert(struct phys2d_edge *edge, int index);
-float phys2d_edge_moi(struct phys2d_edge *edge, float m);
+float phys2d_edge_moi(struct phys2d_edge *edge);
 
 void phys2d_edge_setvert(struct phys2d_edge *edge, int index, cpVect val);
 void phys2d_edge_clearverts(struct phys2d_edge *edge);

source/engine/gameobject.c

@@ -93,16 +93,16 @@ void go_shape_apply(cpBody *body, cpShape *shape, gameobject *go) {
 }
 
 void go_shape_moi(cpBody *body, cpShape *shape, gameobject *go) {
-  float moment = cpBodyGetMoment(go->body);
+  float moment = cpBodyGetMoment(body);
   struct phys2d_shape *s = cpShapeGetUserData(shape);
   if (!s) {
-    cpBodySetMoment(go->body, moment + 1);
+    cpBodySetMoment(body, moment + 1);
     return;
   }
 
-  moment += s->moi(s->data, go->mass);
+  moment += s->moi(s->data);
-  if (moment < 0) moment = 1;
+  if (moment < 0) moment = 0;
-  cpBodySetMoment(go->body, 1);
+  cpBodySetMoment(body, moment);
 }
 
 void gameobject_apply(gameobject *go) {

source/engine/jsffi.c

@@ -1370,6 +1370,18 @@ JSValue duk_cmd(JSContext *js, JSValueConst this, int argc, JSValueConst *argv)
     case 220:
       ret = num2js(js2sprite(argv[1])->drawmode);
       break;
+    case 221:
+      ret = ptr2js(cpPivotJointNew(js2gameobject(argv[1])->body, js2gameobject(argv[2])->body,js2vec2(argv[3]).cp));
+      cpSpaceAddConstraint(space,js2ptr(ret));
+      break;
+    case 222:
+      ret = ptr2js(cpPinJointNew(js2gameobject(argv[1])->body, js2gameobject(argv[2])->body, cpvzero,cpvzero));
+      cpSpaceAddConstraint(space, js2ptr(ret));
+      break;
+    case 223:
+      ret = ptr2js(cpGearJointNew(js2gameobject(argv[1])->body, js2gameobject(argv[2])->body, js2number(argv[3]), js2number(argv[4])));
+      cpSpaceAddConstraint(space,js2ptr(ret));
+      break;
   }
 
   if (str)
@@ -1706,8 +1718,8 @@ JSValue duk_cmd_circle2d(JSContext *js, JSValueConst this, int argc, JSValueCons
     case 3:
       return vec2js(circle->offset);
   }
+  phys2d_shape_apply(&circle->shape);
 
-  phys2d_applycircle(circle);
   return JS_UNDEFINED;
 }