示例代码5-2 带有撞击边界的盒子着落模拟
// A fixed boundary classclass Boundary { // A boundary is a simple rectangle with x,y,width,and height float x; float y; float w; float h; // But we also have to make a body for box2d to know about it Body b; Boundary(float x_,float y_, float w_, float h_) { x = x_; y = y_; w = w_; h = h_; // Define the polygon PolygonShape ps = new PolygonShape(); // Figure out the box2d coordinates float box2dW = box2d.scalarPixelsToWorld(w/2); float box2dH = box2d.scalarPixelsToWorld(h/2); // We're just a box ps.setAsBox(box2dW, box2dH); // Create the body BodyDef bd = new BodyDef(); bd.type = BodyType.STATIC; bd.position.set(box2d.coordPixelsToWorld(x,y)); b = box2d.createBody(bd); // Attached the shape to the body using a Fixture b.createFixture(ps,1); } // Draw the boundary, if it were at an angle we'd have to do something fancier void display() { fill(0); stroke(0); rectMode(CENTER); rect(x,y,w,h); }}3、运行效果
