concept wizard in category scratch
This is an excerpt from Manning's book Hello Scratch!: Learn to program by making arcade games.
you’ve now seen a third way to clone a sprite. This one is most commonly used to generate sprite copies during the game rather than create those copies before the game begins. For instance, you may want a game with two crabs in it. You can draw one crab and use the Duplicator tool to make a second, programmable copy of that crab before the game begins, for a total of two crabs. The Duplicator tool can save you a lot of time and work. But the Create Clone of Myself block generates clones while the game is running. Later, you will make a shoot-em-up game in this book called Wizards vs. Ghosts. As the ghosts fall and the wizard blasts them away with his wand, you’ll need the Create Clone of Myself block to generate new copies of the ghost sprite so there will always be ghosts to shoot on the screen.
Like Astrosmash, the goal of Wizards vs. Ghosts is to shoot the ghosts coming at you with sparks from your wand while trying not to get hit by any of the apparitions. The ghosts won’t break apart like the rocks in Asteroids or Astrosmash but instead disappear from the screen when blasted by the wizard’s spell, as shown in figure 7.1.
Figure 7.1. In Wizards vs. Ghosts, the player moves the wizard back and forth while blasting ghosts with his wand. The player loses a life whenever he touches a ghost, loses points whenever a ghost touches the ground, and gains points whenever he blasts one away.
Wizards vs. Ghosts is a fixed shooter, which means the sprite doing the blasting (in this case, the wizard) can only move back and forth on one fixed plane on the screen. You can’t make the wizard fly above the ghosts, and you can’t get him to hide in the grass. He can only move across the ground while fighting the ghosts. Additionally, the scenery is fixed and remains the same—a big, open field—throughout the whole game rather than changing as the player moves through a larger universe. The player is looking at the action from the side as if it is happening in front of them.
The wizard is the equivalent to the space cannon in Astrosmash. You will move him back and forth along the grass using the arrow keys while you press the spacebar to fire spells from his wand. Three programs power the wizard: a movement script, a life deducting script, and a game ending script. All scripts in this section are applied to the wizard, so go put the blue box around the wizard sprite in the Sprite Zone and don’t move the blue box until you program the ghost in the next section. Remember, the names or values on your blocks may be slightly different from time to time, so use the completed script images to make sure you choose the correct block.