Problem Definition: To develop a snack game using java applet.
Data Structure: A Queue with 2-D array .
Logic Description :
- In this program Queue is implemented with 2-D array which contains f (front) and r (rear) to point head and tail of snake.
- Seven variables shown in below image contain data about each of line that the snake moves according to key pressed.
- The value of ‘ f ’ is incremented when a new line of the snake is generated. And ‘ r ’ is incremented when the last line of snake gets its length to zero, as shown below.
- As Shown in above figure when up button pressed ‘ f ‘ is incremented from index 0 to 1 and all seven variable rows will be initialized as below:
- (x1,y1) will be copied to (x0,y0) and (x1,y1) of new line
- length will be 0, and incremented in iteration.
- Direction will be set according the key pressed.
- The length of a line to which ‘ r ‘ points will be decremented in each iteration.
- When a new line pointed by ‘ f ‘ goes over the boundary of screen a new line is generated from opposite side in a same direction of previous one , and now ‘ f ‘ will point to that newly generated line.
- And rows data for new entry is initialized.
Get the Point:
- A random function is used to generate the point that going to be eaten by snake.
- To make it visible enough u can make rectangle of 1X1, so that it acquires 4 pixel and can be visible enough.
- When header point (x1,y1) of ‘ f ‘ line meets the randomly generated point/rectangle length of 'r ’ line is incremented, no other changes require.
- In this section it is checked that, whether the header point of ‘ f ‘ line is meets to any existing point of snake.
- For that whole the Queue from ‘ r ‘ to ‘ f ‘ is traced.
It divides this checking in two parts,
First one, for all the lines having upward or downward direction (with Direction flag 2 or 4).
- First we needs to check whether X-coordinate of header point(x1,y1) and X-coordinate of existing line is same or not?
- If its not then there will no match, but if it is same than we have two option as shown in above figure.
- For that now we needs to check for Y-coordinate of header point and existing ling by trashing from y0 to y1 for each vertical existing line.
- Same method can be applied for next option for Horizontal lines with direction of Right side or left side (Direction flag 1 or 3).
You can find the code & game, by clicking here.
Enjoy gaming with Java Applet!