[JAVA][Beginning Java 8 Games Development]

Chapter 16 ■ Collision Detection: Creating SVG Polygons for the Game Actors and Writing Code to Detect Collision
The SVG Data Format: Hand Coding Vector Shapes
There are ten different letters that can be utilized with the numeric (X,Y data point location in 2D space) data in an
SVG data string. Each has an upper case (absolute referencing) and a lower case (relative referencing) version. We will
be using absolute referencing as we need these data points to match up with pixel locations in the sprite imagery that
we are going to “attach” or group these SVG Path data strings with to provide collision detection data guidelines. As
you can see in Table 16-1, the SVG data commands provide you a great deal of flexibility in defining custom curves for
your Java 8 game development. You could even combine all of these scalable vector commands with your Java 8 code
to create interactive vector (digital illustration) artwork that has never before been experienced, but since this is a
game development title, we’re going to use this information to develop highly optimized collision polygons that only
use a dozen X,Y data points (somewhere between 12 and 15) to define a relatively detailed collision polygon that will
encase our sprite imagery, and provide highly accurate (from the game player’s viewpoint, at least) collision results.
Table 16-1. SVG data commands to use for creating SVG path data string (source: Worldwide Web Consortium w3.org)
SVG Command Name Symbol Type Parameter Description
moveto M Absolute X, Y Defines a Start Of Path at the X,Y using
absolute coordinates
moveto m Relative X, Y Defines a Start Of Path at the X,Y using
relative coordinates
closepath Z Absolute None Close SVG Path, by drawing line from last to
first coordinate
closepath z Relative None Close SVG Path, by drawing line from last to
first coordinate
lineto L Absolute X, Y Draws a Line from the current point to the
next coordinate
lineto l Relative X, Y Draws a Line from the current point to the
next coordinate
horizontal lineto H Absolute X Draws a Horizontal Line from current point to
next coordinate
horizontal lineto h Relative X Draws a Horizontal Line from current point to
next coordinate
vertical lineto V Absolute Y Draws a Vertical Line from current point to
next coordinate
vertical lineto v Relative Y Draws a Vertical Line from current point to
next coordinate
curveto C Absolute X,Y, X,Y, X,Y Draws a cubic Bezier curve from current
point to next point
curveto c Relative X,Y, X,Y, X,Y Draws a cubic Bezier curve from current
point to next point
shortandsmoothcurve S Absolute X,Y, X,Y Draws a cubic Bezier curve from current
point to next point
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