[JAVA][Beginning Java 8 Games Development]

Chapter 16 ■ Collision Detection: Creating SVG Polygons for the Game Actors and Writing Code to Detect Collision
Figure 16-23. Fine-tune your vertex placement for the collision polygon in the PhysicsEditor, then select your Exporter
The closer you can get the collision polygon to the outline of the sprite, optimally you would want to put it right
on top of the anti-aliasing that is on the pixel-edge between the sprite pixels and the transparency, or even right inside
of the anti-aliasing if you want a more challenging game play. Ultimately, your collision polygons will have to be
tweaked during your game development and game testing cycles, so that you get the most realistic result during your
game play. If you’re developing for powerful platforms such as game consoles, you can add data points to the collision
polygon, and if you’re developing for single or dual processor platforms, such as HTML5 phones or iTVs, use less data.
Replacing Dummy Collision Data: InvinciBagel.java
Next, let’s make some changes to your Java code in the InvinciBagel.java class, so that you are actually using this
highly optimized collision polygon data that we just developed during this chapter. We will use the data set that has
only 15 data points, so that we can see all of our collision polygon data in our NetBeans 8.0 code editing pane. As you
can see in Figure 16-24, we will need to put the Bagel() constructor method call on three different lines: one for the
iBagel = new Bagel(this) part of the instantiation, another for the collision polygon SVG data String object, and
another for the xLocation, yLocation and Image object List. We will also be using our knowledge of SVG commands,
which we learned from Table 16-1, to create the collision polygon data for our tileable brick elements. We will be using
these brick “Prop” elements to develop our collision detection Java code later on in the chapter. We will create these
simpler collision polygons using only our brains, by implementing numeric logic that relates to the resolution of the
brick image, and where the corner pixel locations would be in X,Y coordinate space, in conjunction with the SVG path
drawing commands that we learned about in Table 16-1. You are becoming quite a game development professional!
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