package com.joye3g.joint; import com.badlogic.gdx.ApplicationListener; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.GL10; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.BodyDef; import com.badlogic.gdx.physics.box2d.BodyDef.BodyType; import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer; import com.badlogic.gdx.physics.box2d.CircleShape; import com.badlogic.gdx.physics.box2d.EdgeShape; import com.badlogic.gdx.physics.box2d.FixtureDef; import com.badlogic.gdx.physics.box2d.PolygonShape; import com.badlogic.gdx.physics.box2d.World; import com.badlogic.gdx.physics.box2d.joints.WeldJointDef; import com.joye3g.joint.util.Transform; public class WeldJointDemo implements ApplicationListener{ private Box2DDebugRenderer renderer; private OrthographicCamera camera; private static final float PXTM = 30; private World mWorld; @Override public void create() { float screenWidth = Gdx.graphics.getWidth(); float screenHeight = Gdx.graphics.getHeight(); renderer = new Box2DDebugRenderer(); camera = new OrthographicCamera(screenWidth / PXTM, screenHeight / PXTM); mWorld = new World(new Vector2(0f, -7f), true); //绘制地面 BodyDef bodyDef = new BodyDef(); bodyDef.type = BodyType.StaticBody; bodyDef.position.set(-screenWidth / PXTM / 2, -screenHeight / PXTM / 2); Body mLine = mWorld.createBody(bodyDef); EdgeShape edgeShape = new EdgeShape(); edgeShape.set(new Vector2(0f, 1f), new Vector2(screenWidth / PXTM, 1f)); FixtureDef fixtureDef = new FixtureDef(); fixtureDef.shape = edgeShape; mLine.createFixture(fixtureDef); //绘制一个长方形 BodyDef mRecBodyDef1 = new BodyDef(); mRecBodyDef1.type = BodyType.DynamicBody; //长方形的位置在屏幕(60,190)的位置 Vector2 vector1 = Transform.ptm(60f, 190f, screenWidth, screenHeight, 0f, 0f, PXTM); mRecBodyDef1.position.set(vector1); Body mRecBody1 = mWorld.createBody(mRecBodyDef1); PolygonShape mRecShape1 = new PolygonShape(); mRecShape1.setAsBox(1f, 1f); FixtureDef mCircleFix1 = new FixtureDef(); mCircleFix1.shape = mRecShape1; mCircleFix1.density = 3.0f;//两个Body都必须设置此项 mRecBody1.createFixture(mCircleFix1); //绘制一个长方形 BodyDef mRecBodyDef2 = new BodyDef(); mRecBodyDef2.type = BodyType.DynamicBody; //长方形的位置在屏幕(200,190)的位置 Vector2 vector2 = Transform.ptm(200f, 190f, screenWidth, screenHeight, 0f, 0f, PXTM); mRecBodyDef2.position.set(vector2); Body mRecBody2 = mWorld.createBody(mRecBodyDef2); PolygonShape mRecShape2 = new PolygonShape(); mRecShape2.setAsBox(3.6f, 1f); FixtureDef mCircleFix2 = new FixtureDef(); mCircleFix2.shape = mRecShape2; mCircleFix2.density = 3.0f;//两个Body都必须设置此项 mRecBody2.createFixture(mCircleFix2); //绘制一个半径为1米的圆形(静态) BodyDef mCircleBodyDef3 = new BodyDef(); mCircleBodyDef3.type = BodyType.StaticBody; //圆形的位置在屏幕(60,100)的位置 Vector2 vector3 = Transform.ptm(60f, 100f, screenWidth, screenHeight, 0f, 0f, PXTM); mCircleBodyDef3.position.set(vector3); Body mCircle3 = mWorld.createBody(mCircleBodyDef3); CircleShape mCircleShape3 = new CircleShape(); mCircleShape3.setRadius(1f); FixtureDef mCircleFix3 = new FixtureDef(); mCircleFix3.shape = mCircleShape3; mCircle3.createFixture(mCircleFix3); //创建一个焊接关节 WeldJointDef weldJointDef = new WeldJointDef(); weldJointDef.initialize(mRecBody1, mRecBody2, mRecBody1.getWorldCenter()); mWorld.createJoint(weldJointDef); } @Override public void resize(int width, int height) { } @Override public void render() { GL10 gl=Gdx.graphics.getGL10(); gl.glClear(GL10.GL_COLOR_BUFFER_BIT); mWorld.step(Gdx.graphics.getDeltaTime(), 8, 6); renderer.render(mWorld, camera.combined); } @Override public void pause() { } @Override public void resume() { } @Override public void dispose() { } }
package com.joye3g.joint.util; import com.badlogic.gdx.math.Vector2; public class Transform { /** * @param x_px 图片所在x坐标 * @param y_px 图片所在y坐标 * @param screenWidth 屏幕宽度 * @param screenHeight 屏幕高度 * @param width_px 图片宽度 * @param height_px 图片高度 * @param scale 缩放比例 * @return (x,y)直接设置为body的position可使body与图片重合 */ public static Vector2 ptm(float x_px, float y_px, float screenWidth, float screenHeight, float width_px, float height_px, float scale){ Vector2 vector2 = new Vector2(); vector2.x = -(screenWidth - x_px * 2 - width_px) / scale / 2; vector2.y = -(screenHeight - y_px * 2 - height_px) / scale / 2; return vector2; } /** * @param x_m body所在x坐标 * @param y_m body所在y坐标 * @param screenWidth 屏幕宽度 * @param screenHeight 屏幕高度 * @param wh (x,y)body的宽高 * @param scale 缩放比例 * @return (x,y)直接设置为图片的position可使图片与body重合 */ public static Vector2 mtp(float x_m, float y_m, float screenWidth, float screenHeight, Vector2 wh, float scale){ Vector2 vector2 = new Vector2(); vector2.x = x_m * scale + screenWidth / 2 - wh.x * scale; vector2.y = y_m * scale + screenHeight / 2 - wh.y * scale; return vector2; } }