Book Image

Torque 3D Game Development Cookbook

By : DAVID WYAND
Book Image

Torque 3D Game Development Cookbook

By: DAVID WYAND

Overview of this book

Torque 3D is a popular game engine that supports you in every step along the way to making your game a reality. Even with all of the power and tools that Torque 3D provides, finishing a high quality 3D game requires time and knowledge."Torque 3D Game Development Cookbook" is a practical guide that takes you through each of the major steps on the journey to creating your game, while learning a few tricks along the way.The recipes in this book start off with learning some of the finer points about TorqueScript. The book then moves on to each of Torque 3D's subsystems and ends with a variety of game play recipes.The various topics covered include activating level-specific game code and scheduling game events, dragging and dropping items between windows to work with an in-game inventory system, and covering the seams between objects with well placed decals. Some of the advanced topics include writing custom shaders and postFX, using zones to improve rendering performance, and enhancing your game's ambience through sound.Once you are done with Torque 3D Game Development Cookbook you'll be on your way to creating amazing 3D games and gain expert knowledge of Torque 3D.
Table of Contents (17 chapters)
Torque 3D Game Development Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Retrieving components of a variable using accessors


Under TorqueScript position, vector, matrix, and color variables are all very similar. They are made up of a string with space-delimited components (or fields). For example, a position variable may be defined as follows:

// A position is of the form "x y z"
%position = "1.2 0.34 13.22";

TorqueScript provides a set of special accessors to work with these common types of variables. This allows us to access each individual component and manipulate it.

Getting ready

We will be adding a new TorqueScript function to a project based on the Torque 3D Full template and try it out using the Empty Terrain level. If you haven't already, use the Torque Project Manager (Project Manager.exe) to create a new project from the Full template. It will be found under the My Projects directory. Then start up your favorite script editor, such as Torsion, and let's get going!

How to do it...

We are going to write a TorqueScript function that will demonstrate how to retrieve components of a variable using the special accessors as follows:

  1. Open the game/scripts/server/game.cs script file and add the following code to the bottom:

    function variableAccessors1()
    {
       // A position is of the form "x y z"
       %position = "23.0 2.35 9.78";
       
       // Print out each component to the console
       echo("Position X: " @ %position.x);
       echo("         Y: " @ %position.y);
       echo("         Z: " @ %position.z);
       echo("\n");
       
       // Add one to the position's y component
       %position.y += 1;
       
       // Print out each component to the console
       echo("New Position X: " @ %position.x);
       echo("             Y: " @ %position.y);
       echo("             Z: " @ %position.z);
       echo("\n");
       
       // Define a vector in the form of "x y z w"
       %vector = "1 0 0 1";
       
       // Print out each component to the console
       echo("Vector X: " @ %vector.x);
       echo("       Y: " @ %vector.y);
       echo("       Z: " @ %vector.z);
       echo("       W: " @ %vector.w);
       echo("\n");
       
       // A color is of the form "r g b a"
       %color = "128 0 128 255";
       
       // Print out each color component to the console
       echo("Color R: " @ %color.r);
       echo("      G: " @ %color.g);
       echo("      B: " @ %color.b);
       echo("      A: " @ %color.a);
       echo("\n");
       
       // Modify the color components
       %color.r += 64;
       %color.g += 64;
       %color.b = 0;
       
       // Print out each color component to the console
       echo("New Color R: " @ %color.r);
       echo("          G: " @ %color.g);
       echo("          B: " @ %color.b);
       echo("          A: " @ %color.a);
    }
  2. Start up our game under the My Projects directory and load the Empty Terrain level. Open the console using the tilde (~) key and enter the following at the bottom of the screen:

    variableAccessors1();
    

    In the console we will see the following output:

    ==>variableAccessors1();
    Position X: 23.0
             Y: 2.35
             Z: 9.78
    
    New Position X: 23.0
                 Y: 3.35
                 Z: 9.78
    
    Vector X: 1
           Y: 0
           Z: 0
           W: 1
    
    Color R: 128
          G: 0
          B: 128
          A: 255
    
    New Color R: 192
              G: 64
              B: 0
              A: 255
    

How it works...

TorqueScript provides two sets of convenience accessors to help work with components of a variable. The first set is x, y, z, and w. This set is most often used with the x, y, and z components of position and vector variables; and we will nearly always use the first three accessors, ignoring the w accessor. The second set is r, g, b, and a, which correspond to the red, green, blue, and alpha components of a variable containing color information.

There's more...

Behind the scenes, whenever we use one of these special accessors, TorqueScript is retrieving the corresponding space-delimited field within the variable. So the x and r accessors refer to the first field, the y and g accessors refer to the second field, and so on.

This also means that the positional/vector accessors and color accessors can be freely mixed together. For example, the red component of a color variable may just as easily be retrieved using the x accessor, and the alpha component may be retrieved with the w accessor. This also works the other way round with the components of a vector retrieved using the color accessors. We can see this in action by copying the following function at the end of the game/scripts/server/game.cs script file:

function variableAccessors2()
{
   // Define a vector in the form of "x y z w"
   %vector = "1 0 0 1";
   
   // Print out each xyzw component to the console
   echo("Vector X: " @ %vector.x);
   echo("       Y: " @ %vector.y);
   echo("       Z: " @ %vector.z);
   echo("       W: " @ %vector.w);
   echo("\n");
   
   // Print out each rgba component to the console
   echo("Vector R: " @ %vector.r);
   echo("       G: " @ %vector.g);
   echo("       B: " @ %vector.b);
   echo("       A: " @ %vector.a);
}

Start up our game under the My Projects directory and load the Empty Terrain level. Open the console using the tilde (~) key and enter the following at the bottom of the screen:

variableAccessors2();

In the console we will see the following output:

==>variableAccessors2();
Vector X: 1
       Y: 0
       Z: 0
       W: 1


Vector R: 1
       G: 0
       B: 0
       A: 1

The results demonstrate that we can retrieve components of a variable using either set of accessors.

See also

  • Accessing delimited fields within a string