Toppop

Toppop
Physical Prototype
Dominik Borer
Francine Rotzetter
Marie Woon
Serge Balzan
Game Programming Lab
March 2016
Contents
1 Introduction
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2 Game Elements
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3 Gameplay
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4 Physics
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5 Conclusion
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5.1 Creating the Prototype . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 Playing the Game . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3 Listing of Details Discussed . . . . . . . . . . . . . . . . . . . . . . . . . .
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1 Introduction
As Toppop is a game that relies heavily on its physics, we expected to have a dicult
time with the paper prototype right from the beginning. However since the game is
also essentially 2D, prototyping levels themselves should not be too dicult. With that
in mind, we set out to create some levels to play through on paper. Surprisingly, we
managed to nd out quite a number of details through playtesting and discussing the
prototype step by step.
2 Game Elements
To keep it simple, only a few of the planned game elements are represented in the physical
prototype. These elements are:
• The starting location
• Platforms which preserve energy
• Platforms which add energy
• Platforms which remove energy
• The goal
Because the game is level based, we can aord to only test the very basic elements at
this stage and return to paper-prototyping additional elements when we have made sure
that the basic ones are working correctly. This limited selection also allows us to focus
our eorts more on the core game play.
Every level is also necessarily bounded by a box around it. This box provides a condition
for the player to lose and limits the size of the level.
3 Gameplay
At the beginning of the game, the player is faced with the level. A small yellow dot
represents the starting point and the word goal is written somewhere else to indicate the
location the player has to reach. The levels are lled with blue, green and red platforms.
The blue ones represent the energy removing platforms, the green ones represent energy
preserving platforms and the red ones represent energy adding platforms.
The player starts by telling the person playing the computer in which direction they
want to rotate. The token is then moved accordingly. The game continues in this fashion
until the player's token has to bounce on an object. Now the computer has to determine
the direction in which the character token bounces. The player can now only choose to
change their rotation. The token's direction is now determined mostly by the person
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simulating the physics.
At any point during the level, the player can decide to pop the corn kernel (his token).
The kernel is then replaced with the popcorn. If at that point the popcorn is in contact
with another solid object (i.e. a platform), the popcorn will receive additional acceleration along the normal direction of the object's surface. To win, the player has to successfully reach the goal. Getting stuck, or falling o the provided platforms constitutes a loss.
Figure 1: Hard level including the solution.
Included here are some photos of the paper prototype of this level as we were playing
it. The coloring of the platforms is as follows: brown - preserve energy, green - remove
energy, orange - add energy.
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Figure 2: Beginning of the level. The player has moved to the right.
Figure 3: Having navigated to the left, the corn kernel bounces up the platforms.
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Figure 4: The corn kernel has bounced across the horizontal platform.
Figure 5: The corn kernel has popped and was replaced by a popcorn.
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4 Physics
The phyiscal behaviour is controlled by the player who simulates the computer. When
the player wants to move their character, the rolling properties are just assumed and the
character token is moved forwards on the grid. Every time the character token bounces,
the player has to decide to rotate clockwise or counter-clockwise and the person playing
the computer has to determine in which direction and how many squares the token will
move. For the popping action, the character token is swapped out so that the change is
represented visually.
Of course some interactions will not be 100% correct, but when there is disagreement
among the participants about where the token should be headed, this results in an
opportunity to discuss the relevant forces and how they should be applied in the situation.
5 Conclusion
5.1 Creating the Prototype
Making the prototype turned out to be quite dicult. Since our game mechanics are
heavily based on physics, it does not translate very well into a paper prototype. The
player should be able to control the corn's rotation while being aected by the environment in a physically correct manner.
For earlier prototypes, each level was created using a scale that showed how high the corn
could pop. Everything in the levels was then made according to this measure and each
level turned out to be dierent. In the end we decided to use a grid based representation,
where the player moves their corn kernel or popcorn from one grid cell to the next instead
of rolling. The physical behaviour (falling, jumping, bouncing etc.) is controlled by the
player who simulates the computer. The grid also helped us to simulate the proportions
of the individual elements.
Through creating the prototype, we thought about the physics model of our game and
how the corn kernel / popcorn bounces o platforms. This led to the conclusion that the
movement of the player should be controlled through its rotation, which furthermore has
to be used to control the bouncing angle.
5.2 Playing the Game
Through playing the game, we realised that there are two major components which make
Toppop engaging. The rst one is the puzzle aspect we had aimed for from the beginning. The intended solution to some levels that were tested were not immediately clear
to those who did not participate in the creation of the level.
The second aspect is the actual platform layout. Navigating through the level provides a
more skill based challenge for the player. The part which requires skill (using the rotation
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and physical behaviour in the right way) is mostly missing, since the playable version is
very simple and not really controlled by physics. Therefore walking through the levels is
not very fun and less challenging.
The prototype is playable and supports the basic elements, but it is not very fun since
it is obviously missing the interesting, accurate physical simulation part.
However, actually guring out the intended path was quite fun, although this part was
separated from the actual gameplay. When new ideas for levels were shown to other
members of the team, everyone started guessing at the path the player should take to
reach the goal. When the intended path did not quite match up with everyone else's
expectations of the physical behaviour, the level was adjusted to correct the problems.
Though it was not really the focus of our prototyping, we have managed to assert that
there is some fun in creating the levels ourselves. This aspect will also be included into
the game in the form of the level editor. In the actual game, the creator of a level will
also be able to test their level with the help of the actual in-game physics after creating it.
The issues we found are a consequence of the physical prototype and do not translate
back to our game concept.
5.3 Listing of Details Discussed
Although this is not a full list, these are some of the details we discussed during prototyping (in no particular order):
• Reduced the number of necessary elements to just the platforms, the goal and the
character.
• Determined that there should be three types of platforms.
• Determined how the character moves (by rolling, not horizontal translation).
• The corn's speed increases as the rotation increases.
• The corn kernel bounces as well, but is not as bouncy as the popcorn.
• The corn pops in the normal direction of the platform it is currently on.
• Sloped platforms aect the corn's rotation, thereby increasing its speed as it rolls
down. Similarly, slopes will slow the character down if it attempts to roll uphill.
• Noted down a potentially hazardous corner case involving sharp angles between
platforms and bouncing for collision detection.
• Considered letting corns climb on each other in a multiplayer setting.
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• Every level is bounded by a box around it. If the character touches the box the
player loses. The box should be adjustable in the editor.
• The camera moves along with the player in single player mode and with the center
of gravity of all players in multiplayer mode (This was one option considered).
Additionally there may be a death timer when a player leaves the currently visible
screen.
• Discussed the setting / look and feel of the game.
• For multiplayer, players start in dierent locations and have to reach dierent goals.
Which player enters which goal does not matter, but each goal can only be entered
once.
• Determined the size of the popcorn in relation to the corn kernel.
• Creating platforms in the editor will be based on geometric primitives. They can
be moved and rotated, and will be joined together to create larger platforms.
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