function drawWorld(world, context) { for (var j = world.m_jointList; j; j = j.m_next) { drawJoint(j, context); } for (var b = world.m_bodyList; b; b = b.m_next) { for (var s = b.GetShapeList(); s != null; s = s.GetNext()) { drawShape(s, context); } } } function drawJoint(joint, context) { var b1 = joint.m_body1; var b2 = joint.m_body2; var x1 = b1.m_position; var x2 = b2.m_position; var p1 = joint.GetAnchor1(); var p2 = joint.GetAnchor2(); context.strokeStyle = '#00eeee'; context.beginPath(); switch (joint.m_type) { case b2Joint.e_distanceJoint: context.moveTo(p1.x, p1.y); context.lineTo(p2.x, p2.y); break; case b2Joint.e_pulleyJoint: // TODO break; default: if (b1 == world.m_groundBody) { context.moveTo(p1.x, p1.y); context.lineTo(x2.x, x2.y); } else if (b2 == world.m_groundBody) { context.moveTo(p1.x, p1.y); context.lineTo(x1.x, x1.y); } else { context.moveTo(x1.x, x1.y); context.lineTo(p1.x, p1.y); context.lineTo(x2.x, x2.y); context.lineTo(p2.x, p2.y); } break; } context.stroke(); } function drawShape(shape, context) { context.strokeStyle = '#ffffff'; context.beginPath(); switch (shape.m_type) { case b2Shape.e_circleShape: { var circle = shape; var pos = circle.m_position; var r = circle.m_radius; var segments = 16.0; var theta = 0.0; var dtheta = 2.0 * Math.PI / segments; // draw circle context.moveTo(pos.x + r, pos.y); for (var i = 0; i < segments; i++) { var d = new b2Vec2(r * Math.cos(theta), r * Math.sin(theta)); var v = b2Math.AddVV(pos, d); context.lineTo(v.x, v.y); theta += dtheta; } context.lineTo(pos.x + r, pos.y); // draw radius context.moveTo(pos.x, pos.y); var ax = circle.m_R.col1; var pos2 = new b2Vec2(pos.x + r * ax.x, pos.y + r * ax.y); context.lineTo(pos2.x, pos2.y); } break; case b2Shape.e_polyShape: { var poly = shape; var tV = b2Math.AddVV(poly.m_position, b2Math.b2MulMV(poly.m_R, poly.m_vertices[0])); context.moveTo(tV.x, tV.y); for (var i = 0; i < poly.m_vertexCount; i++) { var v = b2Math.AddVV(poly.m_position, b2Math.b2MulMV(poly.m_R, poly.m_vertices[i])); context.lineTo(v.x, v.y); } context.lineTo(tV.x, tV.y); } break; } context.stroke(); }