# 13.6-Full stack Java notes: Flying Game Project | Shell|speed|launchframe

Source: Internet
Author: User
Tags cos rounds sin

Shell Design

Through the design of shells, we can learn more about the use of constructors and the use of containers. At the same time, it may be necessary for the reader to recall a little bit of the trigonometric functions learned in junior maths, so as to better understand the calculation principle of the projectile flight path. Of course, if you forget the knowledge, it doesn't matter, after all, in the actual development of mathematics is seldom involved in the content of the original reason.

Basic design of projectile class

Shells we implemented with a solid yellow ellipse, no longer loading new images. Of course, we can find some of the pictures of the shells in class.

Our logic is to generate shells at the window fixed position (200,200), where the shells are randomly oriented and the boundary bounces.

"Example 1" Shell class

 Cn.sxt.game;Import Java.awt.Color;Import Java.awt.Graphics;public class Shell extends Gameobject {Double degree;Public Shell () {degree = Math.random () *math.pi*2;x = 200;y = 200;width = 10;Height = 10;Speed = 3;}public void Draw (Graphics g) {Save the state of the external incoming object GColor C = G.getcolor ();G.setcolor (Color.yellow);G.filloval ((int) x, (int) y, width, height);Shells flying along any anglex + = Speed*math.cos (degree);Y + = Speed*math.sin (degree);The following code, used to achieve the boundary, the shells bounce back (the principle and play billiards game)if (y>constant.game_height-height| | Y<30) {degree =-degree;}if (x<0| | X>constant.game_width-width) {degree = Math.pi-degree;}Return to external, change back to previous colorG.setcolor (c);}}

Arbitrary angular flight path of shells

Shells fly along any angle, with the core code on two lines:

x + = Speed*math.cos (degree);

Y + = Speed*math.sin (degree);

This is actually used in the first high school trigonometric function, through the cos/sin to the x-axis, the y-axis, so that can be accurate until the x, y coordinate changes. Junior trigonometric Functions Forget the children's shoes, self-brain repair.

650) this.width=650; "Src=" https://s4.51cto.com/wyfs02/M01/9D/9D/wKioL1mCydqSTjiAAAIydJ6TPXs717.png-wh_500x0-wm_ 3-wmp_4-s_1140717924.png "title=" figure. png "alt=" wkiol1mcydqstjiaaaiydj6tpxs717.png-wh_50 "/>

Container Objects Store multiple rounds

To store multiple shells, we manage these objects by defining a container arraylist. Traverse all the objects in the container in the paint method and draw the shells.

"Example 2" Mygameframe class: Add ArrayList

 public class Mygameframe extends Frame {Image bgimg = gameutil.getimage ("images/bg.jpg");Image planeimg = gameutil.getimage ("Images/plane.png");Plane Plane = new Plane (planeimg,300,300,3);arraylist shelllist = new arraylist ();The Paint method works by drawing the entire window and internal content. Automatically called by the system.@Overridepublic void Paint (Graphics g) {G.drawimage (bgimg, 0, 0, NULL);Plane.drawmyself (g); Draw the plane itselfDraw all the bullets in the containerfor (int i=0;i

Run the Mygameframe class, as shown in result 2:

650) this.width=650; "Src=" https://s1.51cto.com/wyfs02/M01/9D/9D/wKioL1mCyiWAqo5tAAGR0UVRs8w661.png-wh_500x0-wm_ 3-wmp_4-s_2486376127.png "title=" Figure 2.png "alt=" Wkiol1mcyiwaqo5taagr0uvrs8w661.png-wh_50 "/>

We can see in Figure 2 generated a number of shells, the game window lively a lot! You can extrapolate think about it, in fact, the game window of multiple monsters, multiple cars, multiple aircraft are generated multiple objects, using containers to manage the unified.

"Full stack Java notes" is a can help you from Zeto long for the full stack of Java Engineer Series of notes. The author is called Mr. G,10 years Java research and development experience, has been in the digital, Aerospace Institute of a Research and development center engaged in software design and research and development work, from small white gradually achieve engineers, senior engineers, architects. Proficient in Java Platform Software development, Master Java EE, familiar with various popular development framework.

The notes contain six parts from shallow into deep:

A-java Introductory Phase

B-Database from beginner to proficient

C-hand Edge mobile front end and web front end

D-j2ee from understanding to combat

13.6-Full stack Java notes: Flying Game Project | Shell|speed|launchframe

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