Transcript Video Game Programming Level One – Platformer

VIDEO GAME PROGRAMMING
INSTRUCTOR
Video Game
Programming
Instructor Here
TEACHER’S ASSISTANT
TA Here
Level One – Platformer
VIDEO GAME PROGRAMMING
PART 1 –Platformer Basics
Objective:
Unpack the platform engine and perform
a test build.
• Step 1 – Platformer Setup
• Step 2 – Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Platformer Setup
• Open Platform Engine.fun
• Change the window title to
Platformer (Your Name)
• Save the project as
Platformer_(Your Name).fun.
VIDEO GAME PROGRAMMING
CONCEPT – Third Party Game Engines
• Third party game engines are suites
of tools and code developed by one
company and purchased by another
to create a game.
• Some examples of third party game
engines are Unreal Engine 3, Source
Engine and C4 Engine.
VIDEO GAME PROGRAMMING
STEP 2: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The project should build without any errors.
VIDEO GAME PROGRAMMING
PART 2 – Initial Asset Setup
Objective:
Import the actors and animation sets
using the Import Wizard. Look at some
options to optimize the animations.
• Step 1 – The Import Wizard
• Step 2 – Reviewing Engine Data
• Step 3 – Save and Test
VIDEO GAME PROGRAMMING
STEP 1: The Import Wizard
• The Import Wizard is located in the
Resources menu.
• Open the Import Wizard and use it
to import the PLYR Actor from
platformer11.fun.
VIDEO GAME PROGRAMMING
FUN CONCEPT – Horizontal Flipping
• Horizontal Flipping is used with animations
to reduce the number of frames needed by
an animation set.
• Horizontal Flipping can be used to have
“Left Walking” and “Right Walking”
animations but only one set of frames.
• Look to see that Horizontal Flipping is
turned on int the PLYR_WALK animation.
VIDEO GAME PROGRAMMING
STEP 2: Reviewing Engine Data
• There is already some data types set up in
the Platformer Engine.
• Take a look at the following data
– PlyrOnWhatSM is a State Machine that
determines whether the Sprite it is attached to
is on a platform or in the air.
– My Functions here there are several
prewritten functions to deal with various tasks
in the platformer game.
VIDEO GAME PROGRAMMING
STEP 2: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The project should build without any errors.
VIDEO GAME PROGRAMMING
PART 3 – Levels
Objective:
Add the levels to be in the game.
• Step
• Step
• Step
• Step
1
2
3
4
–
–
–
–
Add the levels
Bypass to Level_1
Level_1’s Map
Save and Test
VIDEO GAME PROGRAMMING
STEP 2: Reviewing Engine Data
CONTINUED
– GravityFactor is a global value used
for gravity.
– PlayerLD is Local data to store values
such as the player’s jumping power and
speed.
VIDEO GAME PROGRAMMING
FUN CONCEPT – Adding Levels
• Sometimes it is good to add all of the
levels that are fundamentally different
at the same time.
• When levels are added later, a copy of
another level can be made so
information doesn’t need to be set up
repeatedly.
VIDEO GAME PROGRAMMING
STEP 1: Add the Levels
• Add a level called TitleScreen.
• Add a level called MainMenu.
• Add a level called Level_1.
VIDEO GAME PROGRAMMING
STEP 2: Bypass to Level_1
• When developing a game it is a waste
of time to have to wait through the
menus so code can be added to jump
to the place we want to test.
VIDEO GAME PROGRAMMING
STEP 2: Bypass to Level_1
• Add the following code to the game’s
OnStart to skip to Level_1:
myGame->LevelName(“Level_1”);
VIDEO GAME PROGRAMMING
STEP 3: Level_1’s Map
• Add a map to Level_1.
• The collision data for the platforms
should be added to this map.
• Each platform will need collision data
pointing up on the top.
• The map should have collision data
added around the edges to keep the
player in the world; the left and right
sides of the map should have a Collision
ID of 1
VIDEO GAME PROGRAMMING
STEP 4: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– When the game is run Level_1 should come up
with the platforms map in the background.
VIDEO GAME PROGRAMMING
PART 4 – The Player
Objective:
Put the player into the game.
• Step 1 – Add the Player Sprite
• Step 2 – Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Add the Player Sprite
• Add the sprite “Player” to Level_1
• Give the player sprite the
PlyrOnWhatSM state machine.
• Give the player sprite the PlayerLD
local data object and set its Display
List to 1.
• Set the player’s collision to precise
and check collision with sprites and
the map.
VIDEO GAME PROGRAMMING
FUN CONCEPT – State Machines
• State Machines are used as a way to
control the behavior of a sprite in Fun.
• State Machines are made up of
different states.
• Edge cases: incoming/outgoing
• Initial Actions vs. Actions
VIDEO GAME PROGRAMMING
STEP 3: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– When the game is run the player should be
able to jump around the screen.
VIDEO GAME PROGRAMMING
PART 5 – The Key
Objective:
Put the Key pickup into the game.
• Step
• Step
• Step
• Step
• Step
1
2
3
4
5
–
–
–
–
–
Import the Key Actor
Add the Key Sprite
Update the PlayerLD
PlayerUpdateFN
Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Import the Key Actor
• Open the Import Wizard and import
the KEY actor from
platformer11.fun.
VIDEO GAME PROGRAMMING
STEP 2: Add the Key Sprite
• Create a new sprite and name it Key.
• Set the Key to only check collision
with other sprites.
• Set the Actor for the Key
VIDEO GAME PROGRAMMING
CONCEPT – Pickups in Games
• Pickups are used for many things in
games such as the rings in Sonic, or
the coins in Mario Bros.
• Pickups can be used for puzzles such
as the key and door scenario.
VIDEO GAME PROGRAMMING
STEP 3: Update the PlayerLD
• Open the PlayerLD local data and add
a boolean variable named HaveKey.
• This value will be used to keep track
of whether or not the player holds the
key, so set the initial value to false.
VIDEO GAME PROGRAMMING
STEP 3: PlayerUpdateFN
Use:
This function will detect when the player
picks up the key and will change the
HaveKey flag in PlayerLD.
• Create an Object Function named
PlayerUpdateFN and enter the following
code for the function body.
• Then add this behavior to the Player sprite
VIDEO GAME PROGRAMMING
PlayerUpdateFN Code
Sprite* key = This->CollisionWithSpritePtr( "Key" );
if ( key )
{
PlayerLD *PlayerData = GetPlayerLD( This );
PlayerData->HaveKey = true;
key->DeleteFlag( true );
}
VIDEO GAME PROGRAMMING
STEP 5: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– When the game is run the player should be
able to pick up the key.
VIDEO GAME PROGRAMMING
PART 6 – The Gate
Objective:
Put the Gate into the game.
• Step
• Step
• Step
• Step
1
2
3
4
–
–
–
–
Import the Gate Actor
Add the Gate Sprite
Modify the PlayerUpdateFN
Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Import the Gate Actor
• Open the Import Wizard and import
the GATE actor from
platformer11.fun.
VIDEO GAME PROGRAMMING
STEP 2: Add the Gate Sprite
• Create a new sprite and name it
Gate.
• Set the Gate to only check collision
with other sprites.
• Set the Actor for the Gate
VIDEO GAME PROGRAMMING
CONCEPT – Sprites as Map Objects
• Using sprites as static level objects
makes it easy to add interactive
objects to the map easily.
• These sprites are just regular sprites
who’s behaviors are set up to make
them seem as though they are part of
the map, much like the gate in
platformer.
VIDEO GAME PROGRAMMING
STEP 3: Modify PlayerUpdateFN
• Update PlayerUpdateFN with the
following bold face code changes.
VIDEO GAME PROGRAMMING
STEP 3: Modify PlayerUpdateFN
Sprite* key = This->CollisionWithSpritePtr( "Key" );
if ( key )
{
PlayerLD *PlayerData = GetPlayerLD( This );
PlayerData->HaveKey = true;
key->DeleteFlag( true );
SpritePTR pGate( "Gate" );
pGate->Animation( GATE_OPENED);
}
if ( This->CollisionWithSprite( "Gate" ) &&
GetPlayerLD( This )->HaveKey )
{
myGame->NextLevel();
}
VIDEO GAME PROGRAMMING
STEP 4: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– When the player picks up the key the gate
should open.
VIDEO GAME PROGRAMMING
PART 7 – Level 2
Objective:
Create Level_2 by making a copy of
Level_1.
• Step 1 – Copy Level_1
• Step 2 – Modify the New Level
• Step 3 – Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Copy Level_1
• Insert a copy of Level_1 and name it
Level_2.
VIDEO GAME PROGRAMMING
STEP 2: Modify the New Level
• Create a map in an art program or
use the provided level art.
• Use this map for Level_2’s map
• Add the collision data to the map.
• Change the key’s position.
• Change the gate’s position.
VIDEO GAME PROGRAMMING
STEP 3: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– Level_2 should display with the new map. Test
and tweak this map to better gameplay.
VIDEO GAME PROGRAMMING
PART 8 – The Enemy Guard
Objective:
Add in a guard and reuse the code for
the behavior.
• Step
• Step
• Step
• Step
• Step
1
2
3
4
5
–
–
–
–
–
Import the Actor
Add the GuardLD
Create EnemyOnWhatSM
Add the Guard Sprite
Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Import the Actor
• Import the ENEMY actor from
platformer11.fun
VIDEO GAME PROGRAMMING
STEP 2: Add the GuardLD
• Add Local Data GuardLD.
• Add a boolean value Jumping with
initial value false.
• Add a float value JumpStrength with
initial value 10.5.
• Add an integer value delay with initial
value 100.
VIDEO GAME PROGRAMMING
STEP 3: Create EnemyOnWhatSM
• Make a copy of PlyrOnWhatSM and
name it EnemyOnWhatSM.
• Replace the code in the platform
state with the following:
VIDEO GAME PROGRAMMING
EnemyOnWhatSM
This->Speed( 2 );
int y = 0;
if(This->LookAheadCollisionWithMap(DOWN, 1, 0))
y = -1;
This->VectorDirection( This->DirectionX(), y );
if( This->DirectionX() )
This->Animation(ENEMY_WALK);
else
This->Animation(ENEMY_IDLE);
VIDEO GAME PROGRAMMING
STEP 3: Create EnemyOnWhatSM
CONTINUED
• Now modify the platform to air edge
which contains return PlayerJump(This);
• Replace the existing code with the
following:
return false;
VIDEO GAME PROGRAMMING
STEP 4: Add the Guard Sprite
• Add an Enemy sprite.
• Give it the ENEMY actor and add the
GuardLD.
• Use EnemyOnWhatSM for the
behavior.
• Position the guard on the map away
from the start position of the player.
VIDEO GAME PROGRAMMING
STEP 5: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– Level_2 should display and the guard should
appear in the level.
VIDEO GAME PROGRAMMING
PART 8 – AI for the Enemy Guard
Objective:
Give the guard an update function that
will make the guard appear to be
somewhat intelligence.
• Step 1 – EnemyUpdateFN
• Step 2 – Save and Test
VIDEO GAME PROGRAMMING
CONCEPT – Artificial Intelligence (AI)
• One of the most important parts of a
game is the AI.
• In games the AI gives the illusion that
characters and objects have
intelligence.
• Many AI systems i.e. Neural
Networks, Fuzzy Logic Systems,
Genetic Algorithms, etc…
VIDEO GAME PROGRAMMING
CONCEPT – Artificial Intelligence (AI)
CONTINUED
• It is easy to make unbeatable AI’s,
but hard to make balanced AI’s that
still seem intelligent.
• Some well known AI examples, alien
attack paths in Galaga, the guards in
Metal Gear Solid, etc…
VIDEO GAME PROGRAMMING
STEP 1: EnemyUpdateFN
• Add the Object Function
EnemyUpdateFN.
• Enter the following code into the
function body.
• Then add this function to the Enemy
sprite’s behavior.
VIDEO GAME PROGRAMMING
EnemyUpdateFN
if ( This->DirectionY() == 0 )
{
GuardLD* guardData = GetGuardLD(This);
if ( guardData->delay <= 0 )
{
SpritePTR pPlayer("Player");
This->VectorDirection( pPlayer->WorldPositionX() This->WorldPositionX(), 0 );
guardData->delay = RandInt(30) + 15;
}
if ( guardData->delay > 0 )
guardData->delay = guardData->delay - 1;
}
VIDEO GAME PROGRAMMING
STEP 2: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The guard should now go after the player.
VIDEO GAME PROGRAMMING
PART 9 –Making the Enemy Jump
Objective:
Modify the EnemyUpdateFN with code
that will make the enemy jump for the
player.
• Step
• Step
• Step
• Step
• Step
1
2
3
4
5
–
–
–
–
–
Modify EnemyUpdateFN
Add GuardJump function
Modify GuardOnWhatSM
Add Collision with the Enemy
Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Modify EnemyUpdateFN
• Modify EnemyUpdateFN by adding
the following lines of code to the
bottom of the function body.
VIDEO GAME PROGRAMMING
EnemyUpdateFN (update)
SpritePTR pPlayer("Player");
bool RightUnder =
( pPlayer->WorldPositionY() < This->WorldPositionY() ) &&
( abs( pPlayer->WorldPositionX() – This->WorldPositionX() )
< 10 );
bool RealClose = This->Distance( pPlayer ) < 80;
if ( RightUnder || RealClose )
{
guardData->Jumping = true;
}
} // This is the closing bracket, it is already there
VIDEO GAME PROGRAMMING
CONCEPT – Customizing Open Source
Game Engines
• When using an open source 3rd party
game engine, it can be easier to copy
one of the functions and simply
modify it instead of creating the
function yourself.
• Modification rules are covered in the
open source aggreement.
VIDEO GAME PROGRAMMING
STEP 2: Add GuardJump function
• Insert a copy of the My Function
PlayerJump and name it
GuardJump.
• Modify the code to reflect the
following bold face changes.
VIDEO GAME PROGRAMMING
GuardJump (update)
GuardLD *guardld = GetGuardLD( This );
if ( guardld->Jumping )
{
float vx = SpriteVectorX(This);
// Horizontal vector component
float vy = -guardld->JumpStrength; // Vertical vector component
SpriteVectorX(This, vx);
SpriteVectorY(This, vy);
guardld->Jumping = false;
return true;
}
else
return false;
VIDEO GAME PROGRAMMING
STEP 3: Modify EnemyOnWhatSM
• Now modify the platform to air edge
which contains return false;
• Replace the existing code with the
following:
GuardJump(This);
VIDEO GAME PROGRAMMING
STEP 4: Add Collision with the Enemy
• We must now edit the
PlayerUpdateFN to allow the
player to collide with the enemy.
• Add the following code to the
bottom of the funtion:
if ( This->CollisionWithSprite( "Enemy" ) )
{
myGame->RestartLevel();
}
VIDEO GAME PROGRAMMING
STEP 5: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The guard should jump after the player now.
VIDEO GAME PROGRAMMING
PART 10 – The Menus
Objective:
Put the maps into the menu levels and
add in behavior to start the game.
• Step
• Step
• Step
• Step
1
2
3
4
–
–
–
–
Add the maps
Add the behaviors
Modify the Game’s OnStart
Save and Test
VIDEO GAME PROGRAMMING
STEP 1 & 2:
• Create the maps, and then add the
maps to the TitleScreen level and add
behaviors to navigate these menus.
Any behavior for the menu is ok such
as a timer, waiting for a key to be
pressed, or taking input from the
mouse.
VIDEO GAME PROGRAMMING
STEP 3: Modify the Game’s OnStart
• Modify the game’s OnStart code to
start with the TitleScreen.
VIDEO GAME PROGRAMMING
STEP 4: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The Levels should fade in and out when
switching.
VIDEO GAME PROGRAMMING
PART 11 – Smooth Transitions Between
Levels
Objective:
Add in transitional effects to the levels to
make the level switches look better.
• Step 1 – Fade in the Levels
• Step 2 – Save and Test
VIDEO GAME PROGRAMMING
STEP 1: Fade in the Levels
• Adjust the Level properties in each of
the levels to have them fade in and
out when switching.
• Adjust fade durations and tweak.
VIDEO GAME PROGRAMMING
STEP 2: Save and Test
• Save the Project:
– Click on Project and Save.
• Run the Project:
– Click on the Build/Run button in the menu
bar.
• Results:
– The Levels should fade in and out when
switching.