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Learn about mouse and keyboard input with the Slick2D game library.

Table of contents

Preface

This module is one in a collection of modules designed to teach you about the anatomy of a game engine.

Although the modules in this collection will concentrate on the Java game library named Slick2D, theconcepts involved and the knowledge that you will gain is applicable to different game engines written in different programming languages as well.

The purpose of this module is to explain some aspects of mouse and keyboard input.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the imagesand listings while you are reading about them.

Figures

  • Figure 1 . Output from the program named Slick0170.java.

Listings

  • Listing 1 . Beginning of the update method.
  • Listing 2 . Test for up or down movement.
  • Listing 3 . Test for collisions with the edges.
  • Listing 4 . Get and save mouse coordinates.
  • Listing 5 . Source code for the program named Slick0170.

Preview

Most games and many simulations are interactive. By that I mean that they require user input to perform according to their design.

I will present and explain a program in this module that allows the user to cause a ladybug sprite (see Figure 1 ) to move inside the game window by pressing the arrow keys on the keyboard or the left and right mousebuttons. (The mouse pointer must be inside the game window for the mouse buttons to move the sprite.)

Figure 1 . Output from the program named Slick0170.java.
Missing image.

Operation

Pressing the right arrow key or the right mouse button causes the sprite to move to the right.

Pressing the left arrow key or the left mouse button causes the sprite to move to the left.

Pressing the up arrow key causes the sprite to move up, and pressing the down arrow key causes the sprite to move down.

The sprite cannot be caused to move up or down (in this program) by pressing mouse buttons.

What you have learned

In the previous module, you learned about using the draw , drawCentered , and drawFlash methods of the Image class.

What you will learn

In this module, you will learn how to use the following methods of the Input class to get input from the user:

  • isKeyDown
  • isMouseButtonDown
  • getMouseX
  • getMouseY

General background information

Modern computer programs fall generally in one or a combination of two categories:

  • Event driven programs
  • Polled programs

Analogy for an event-driven program

I like to think of event-driven programs as being somewhat analogous to the way that we normally drive our cars. When we come to a red stoplight, we removeour foot from the gas pedal, press the brake pedal to stop, and allow the motor to idle, thus consuming minimal fuel. (If we don't have an automatic transmission, we will probably also disengage the clutch and move the gearshiftleaver to the neutral position.)

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Anatomy of a game engine. OpenStax CNX. Feb 07, 2013 Download for free at https://legacy.cnx.org/content/col11489/1.13
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