Lesson 1.4 - Adding a moving sprite
In this lesson, we'll add sprites that move on screen. We'll also learn how to configure the sprite to make it bounce on the screen borders.
Add and position the sprite
1. In the Librarian
window, select the "Media
Files\Images\Sprites" folder (
). The files contained
in this folder are displayed in the list below.
2. Select the
file "Sphere-blue.png"
in the list (
) and use a mouse drag & drop to put the
file in the edit area (
). Place it in the upper-right corner
of the screen at location [490,
100]. The sprite is added in the project and displayed at scale
1:1 (see below). Also, you can see it in the sprite list (
).
TIPS:
To know the exact location of a sprite, look at the bottom of the main
application window. On the right side of the status bar, you'll see a
coordinate indicator (
). Near this indicator is displayed
the exact location of the sprite. You can finely adjust a sprite location
by using the keyboard arrow keys. You can also specify the exact location
by opening the Properties dialog box (Alt+Enter),
select the Size & Position
tab and set X and Y
in the Absolute Position group.

Set the sprite motion parameters
3. Now we're
going to make the sprite move on screen. Double-click on the sprite in
the list (
), see below. A dialog opens. Select the Motion tab if necessary.

4. Choose Straight Line and Bouncing
on the edges of the screen options (
). The first option
indicates the type of motion for this sprite. It will move in straight
line. The second option we've set will make the sprite bounce each time
it will encounter a screen border. Of this option is not set, the sprite
continue its path disappearing under the screen border and reappearing
on the opposite side.
5. Now we'll
set the direction and speed of the sprite. We can do this by specifying
2 values: The Horizontal and Vertical speeds. By choosing these values
(from -500 to +500) we can specify any speed and direction. For the horizontal
speed, a negative value makes the sprite move left, a positive value makes
it move right. For the vertical speed, a negative value makes the sprite
move down, a negative value makes it move up.
Specify -100 in
Horizontal speed and +100
in Vertical speed (
).
6. When done,
click OK. The sprites does not
move, nothing has visually changed. This is because the project is in
"Stopped" state. The sprites are displayed at their original
locations (with resize handles around the selected sprite. To see it move
in the edit window, switch to "Play" mode by clicking on the
Play/Pause button (
). Do you like what you see? Congratulations,
you've made your very first screensaver!
REMARK:
In "play" mode (
), the sprites are moving on screen but you cannot adjust
them (size and position). You can select them by clicking on them while
they're moving but you cannot change their original position and size.
Return to "Stopped"
mode to do so.
7. We can take a look at the result fullscreen. Press F11 or click the Full Screen button in the toolbar. The screensaver is executed fullscreen. Press a key or move the mouse to end the full screen test.
Set the sprite general information
8. Like we did
in the previous lesson, the last operation to do is perform is to specify
some information in the sprite properties. Double-click on the sprite
in the list (
), see above. A dialog box opens, select the
General tab. In the Name
field, specify a short name for the sprite: "Blue
Sphere". This name will be displayed in the sprite list. Also,
specify a Description of the sprite
in the field below.
Exercises
Repeat the procedure with the image file "Sphere-green.png". Place it in the lower-left corner of the screen at location [150, 380]. Specify a straight line path bouncing on the edges of the screen. Specify horizontal speed to +100 and vertical speed to -100. Name this sprite "Green Sphere".
Do the same exercise with the image file "Sphere-red.png". Place it in the upper-left corner of the screen at location [150,100]. Specify a straight line path bouncing on the edges of the screen. Specify horizontal speed to +100 and vertical speed to +100. Name this sprite "Red Sphere".
Test your screensaver project full screen.
Lesson 5 - Adding
an animated sprite