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 Note: | This tutorial is recommended for a bit more experienced Scratchers due to its intricacy. |
What is a 3D environment?
A 3D environment is a place that involves the common X and Y axes, as well as the additional Z axis. The Z axis is a Cartesian coordinate, much like the X and Y axes, but the Z axis usually is the axis for depth. In real life, the Z axis exists, but in Scratch, it does not. We can incorporate size and movement that causes an illusion of depth.
Example using size to create a 3D effect
This script uses sprites and size change for depth perception:
when green flag clicked
set [scroll z v] to [60]
set [scroll y v] to [0]
set [scroll x v] to [-30]
forever
set size to ((scroll z) + ((40) * (0)))%
set x to ((scroll x) + ((480) * (0)))
set y to ((scroll y) + ((360) * (0)))
if <key [up arrow v] pressed?> then
change [scroll z v] by ((size) / (45))
change [scroll x v] by ((x position) / (55))
end
if <key [down arrow v] pressed?> then
change [scroll z v] by ((size) / (-45))
change [scroll x v] by ((x position) / (-55))
end
if <key [left arrow v] pressed?> then
change [scroll x v] by ((size) / (55))
end
if <key [right arrow v] pressed?> then
change [scroll x v] by ((size) / (-55))
end
if < <(scroll z) < [20]> or <(scroll z) > [217]> > then
hide
else
show
end
The "scroll x" and "scroll y" variables' value can be changed so the sprite's position can be changed. The "scroll z" variable is rather special. It does not change the sprite's position, but it changes The size of the sprite.
This method of 3D scripting is very rudimentary, and it does not involve any collision detection, and it would not apply to a moving object.
This is one of the ways you can make the illusion of 3D. Scratch doesn't allow you to make three dimensional games, but it allows you to make the illusion of one. The X axis is the sprites position from left to right. The Y axis is the position from top to bottom, and the Z axis is the sprites size, allowing you to make the sprite small or large. As said in the beginning of this article, we can always incorporate size and movement to create the 3D illusion. If you stroll down a street, you will notice that the farther the things are, the smaller they look. If you put this same principle in video games, you will get a 3D effect. A Raycaster is a more efficient way of 3D in Scratch.
Example using pen and layering
This is a slightly more efficient way of making a 3D illusion. This technique uses layering and stamping. Here is the script:
when flag clicked forever clear go to x(0) y(0) stamp change y by(2) stamp change y by(2) stamp change y by(2) stamp change y by(2) stamp change y by(2) stamp change y by(2) stamp end when green flag clicked forever point towards [mouse-pointer v] end
This method does not use size to create the 3D effect. It changes the position of the sprite and stamps the sprite on the background. This makes several copies of the same sprite, in different positions. This creates a 3D effect.
