Java tutorial
/* * Copyright 2014 Alexey Andreev. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.teavm.samples.benchmark.gwt; import com.google.gwt.canvas.dom.client.Context2d; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.dom.client.CanvasElement; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.user.client.Timer; import com.google.gwt.user.client.ui.RootPanel; import org.jbox2d.collision.shapes.CircleShape; import org.jbox2d.collision.shapes.PolygonShape; import org.jbox2d.collision.shapes.Shape; import org.jbox2d.collision.shapes.ShapeType; import org.jbox2d.common.Vec2; import org.jbox2d.dynamics.Body; import org.jbox2d.dynamics.Fixture; import org.teavm.samples.benchmark.shared.Scene; public class BenchmarkStarter implements EntryPoint { private Document document; private CanvasElement canvas; private Element resultTableBody; private Scene scene = new Scene(); private static int currentSecond; private static long startMillisecond; private static double timeSpentCalculating; @Override public void onModuleLoad() { document = RootPanel.getBodyElement().getOwnerDocument(); canvas = (CanvasElement) document.getElementById("benchmark-canvas"); resultTableBody = document.getElementById("result-table-body"); startMillisecond = System.currentTimeMillis(); makeStep(); } private void makeStep() { double start = Performance.now(); scene.calculate(); double end = Performance.now(); int second = (int) ((System.currentTimeMillis() - startMillisecond) / 1000); if (second > currentSecond) { Element row = document.createElement("tr"); resultTableBody.appendChild(row); Element secondCell = document.createElement("td"); row.appendChild(secondCell); secondCell.appendChild(document.createTextNode(String.valueOf(second))); Element timeCell = document.createElement("td"); row.appendChild(timeCell); timeCell.appendChild(document.createTextNode(String.valueOf(timeSpentCalculating))); timeSpentCalculating = 0; currentSecond = second; } timeSpentCalculating += end - start; render(); new Timer() { @Override public void run() { makeStep(); } }.schedule(scene.timeUntilNextStep()); } private void render() { Context2d context = canvas.getContext2d(); context.setFillStyle("white"); context.setStrokeStyle("grey"); context.fillRect(0, 0, 600, 600); context.save(); context.translate(0, 600); context.scale(1, -1); context.scale(100, 100); context.setLineWidth(0.01); for (Body body = scene.getWorld().getBodyList(); body != null; body = body.getNext()) { Vec2 center = body.getPosition(); context.save(); context.translate(center.x, center.y); context.rotate(body.getAngle()); for (Fixture fixture = body.getFixtureList(); fixture != null; fixture = fixture.getNext()) { Shape shape = fixture.getShape(); if (shape.getType() == ShapeType.CIRCLE) { CircleShape circle = (CircleShape) shape; context.beginPath(); context.arc(circle.m_p.x, circle.m_p.y, circle.getRadius(), 0, Math.PI * 2, true); context.closePath(); context.stroke(); } else if (shape.getType() == ShapeType.POLYGON) { PolygonShape poly = (PolygonShape) shape; Vec2[] vertices = poly.getVertices(); context.beginPath(); context.moveTo(vertices[0].x, vertices[0].y); for (int i = 1; i < poly.getVertexCount(); ++i) { context.lineTo(vertices[i].x, vertices[i].y); } context.closePath(); context.stroke(); } } context.restore(); } context.restore(); } }