The Ring programming language version 1.2 book - Part 38 of 84

1. Ring Documentation, Release 1.2
Screen Shot:
45.26 Using the Game Engine - Object and Drawing
We can use the Object keyword (defined by the game engine) to create objects from the GameObject class.
Example:
Load "gameengine.ring" # Give control to the game engine
func main # Called by the Game Engine
oGame = New Game # Create the Game Object
{
title = "My First Game"
Object {
x = 0 y=300 width = 200 height=200
draw = func oGame,oSelf {
oSelf {
for t = 1 to 210
gl_draw_circle(x,y,t,
gl_map_rgb(t*random(255),
t*2,t*3),1)
45.26. Using the Game Engine - Object and Drawing 350

2. Ring Documentation, Release 1.2
next
}
}
state = func oGame,oSelf {
oSelf {
if x <= 800
x+= 3
else
x=0
ok
}
}
keypress = func oGame,oSelf,nKey {
oSelf {
Switch nKey
on KEY_LEFT
x -= 10
on KEY_RIGHT
x += 10
on KEY_UP
y -= 10
on KEY_DOWN
y += 10
off
}
}
}
} # Start the Events Loop
Screen Shot:
45.26. Using the Game Engine - Object and Drawing 351

3. Ring Documentation, Release 1.2
Example:
Load "gameengine.ring" # Give control to the game engine
func main # Called by the Game Engine
oGame = New Game # Create the Game Object
{
title = "My First Game"
Object {
x = 400 y=300 width = 200 height=200
draw = func oGame,oSelf {
oSelf {
for t = 1 to 210
gl_draw_rectangle(x+t,y+t,
x+t*2,y+t*2,
gl_map_rgb(t*random(255),
t*2,t*3),1)
gl_draw_rectangle(x+t*2,y+t*2,
x-t*2,y-t*2,
gl_map_rgb(t*random(255),
t*2,t*3),1)
next
}
}
45.26. Using the Game Engine - Object and Drawing 352

4. Ring Documentation, Release 1.2
keypress = func oGame,oSelf,nKey {
oSelf {
Switch nKey
on KEY_LEFT
x -= 10
on KEY_RIGHT
x += 10
on KEY_UP
y -= 10
on KEY_DOWN
y += 10
off
}
}
}
} # Start the Events Loop
Screen Shot:
45.27 Stars Fighter Game
The Stars Fighter source code
45.27. Stars Fighter Game 353

5. Ring Documentation, Release 1.2
# The Ring Standard Library
# Game Engine for 2D Games
# 2016, Mahmoud Fayed <msfclipper@yahoo.com>
oGameState = NULL
load "gameengine.ring"
func main
oGame = New Game
while true
oGameState = new GameState
oGame {
title = "Stars Fighter!"
sprite
{
file = "images/menu1.jpg"
x = 0 y=0 width=800 height = 600 scaled = true animate = false
keypress = func ogame,oself,nKey {
if nkey = key_esc or nKey = GE_AC_BACK
ogame.shutdown()
but nKey = key_space
oGameState.startplay=true
ogame.shutdown=true
ok
}
mouse = func ogame,oself,nType,aMouseList {
if nType = GE_MOUSE_UP
oGameState.startplay=true
ogame.shutdown=true
ok
}
}
text {
animate = false
size = 35
file = "fonts/pirulen.ttf"
text = "Stars Fighter"
x = 10 y=50
}
text {
animate = false
size = 25
file = "fonts/pirulen.ttf"
text = "Version 1.0"
x = 80 y=100
}
text {
animate = false
size = 16
file = "fonts/pirulen.ttf"
text = "(C) 2016, Mahmoud Fayed"
x = 45 y=140
}
45.27. Stars Fighter Game 354

6. Ring Documentation, Release 1.2
text {
animate = false
size = 25
file = "fonts/pirulen.ttf"
text = "Press Space to start"
x = 190 y=470
}
text {
animate = false
size = 20
file = "fonts/pirulen.ttf"
text = "Press Esc to Exit"
x = 260 y=510
}
Sound {
file = "sound/music1.wav"
}
}
if oGameState.startplay
oGame.refresh()
playstart(oGame)
oGame.refresh()
ok
end
func playstart oGame
oSound = New Sound {
file = "sound/music2.wav"
}
while true
play(oGame)
if ogame.shutdown = true and oGameState.value = 0
exit
ok
ogame.refresh()
end
oSound.Delete()
func play oGame
oGame
{
FPS = 60
FixedFPS = 120
title = "Stars Fighter!"
sprite
{
file = "images/stars.jpg"
x = 0
y = 0
point = -370
direction = ge_direction_dec
type = ge_type_background
45.27. Stars Fighter Game 355

7. Ring Documentation, Release 1.2
state = func ogame,oself {
oself {
if x < -350
direction = ge_direction_inc
point = 370
but x = 0 and direction = ge_direction_inc
direction = ge_direction_dec
point = -370
ok
}
}
}
sprite
{
file = "images/player.png"
transparent = true
type = ge_type_player
x = 400 y =400 width=100 height=100
animate=false move=true Scaled=true
mouse = func ogame,oself,nType,aMouseList {
if not ( aMouseList[GE_MOUSE_X] >= oSelf.x and
aMouseList[GE_MOUSE_X] <= oSelf.x+oSelf.width and
aMouseList[GE_MOUSE_Y] >= oself.y and
aMouseList[GE_MOUSE_Y] <= oSelf.y+oSelf.height )
if nType = GE_MOUSE_DOWN
if aMouseList[1] < oSelf.X # left
oSelf.X -= 100
else
oSelf.X += 100
ok
if aMouseList[2] < oSelf.Y # up
oSelf.Y -= 100
else
oSelf.Y += 100
ok
ok
else
if nType = GE_MOUSE_UP
cFunc = oself.keypress
call cFunc(oGame,oSelf,Key_Space)
ok
ok
}
keypress = func oGame,oself,nkey {
if nkey = key_space
ogame {
sprite {
type = ge_type_fire
file = "images/rocket.png"
transparent = true
x = oself.x + 30
y = oself.y - 30
width = 30
height = 30
point = -30
45.27. Stars Fighter Game 356

8. Ring Documentation, Release 1.2
nstep = 20
direction = ge_direction_decvertical
state = func oGame,oSelf {
for x in oGame.aObjects
if x.type = ge_type_enemy
if oself.x >= x.x and oself.y >= x.y and
oself.x <= x.x + x.width and
oself.y <= x.y + x.height
showfire(oGame,x.x+40,x.y+40)
ogame.remove(x.nindex)
oGameState.score+=10
oGameState.enemies--
checkwin(oGame)
exit
ok
ok
next
}
}
}
but nkey = key_esc or nKey = GE_AC_BACK ogame.shutdown()
ok
}
state = func oGame,oSelf {
oself {
if x < 0 x = 0 ok
if y < 0 y = 0 ok
if x > ogame.screen_w-width x= ogame.screen_w - width ok
if y > ogame.screen_h-height y=ogame.screen_h-height ok
}
}
}
for g = 1 to oGameState.enemies
sprite
{
type = ge_type_enemy
file = "images/enemy.png"
transparent = true
x = g*random(50) y =g width=100 height=100
animate=true Scaled=true
direction = ge_direction_random
state = func oGame,oSelf {
oself {
if x < 0 x = 0 ok
if y < 0 y = 0 ok
if x > ogame.screen_w-width x= ogame.screen_w - width ok
if y > ogame.screen_h-height y=ogame.screen_h-height ok
}
if random(100) = 1
ogame {
sprite {
type = ge_type_fire
file = "images/rocket2.png"
transparent = true
x = oself.x + 30
y = oself.y + oself.height+ 30
width = 30
height = 30
45.27. Stars Fighter Game 357

9. Ring Documentation, Release 1.2
point = ogame.screen_h+30
nstep = 10
direction = ge_direction_incvertical
state = func oGame,oSelf {
x = oGame.aObjects[oGameState.playerindex]
if oself.x >= x.x and oself.y >= x.y and
oself.x <= x.x + x.width and
oself.y <= x.y + x.height
if oGameState.value > 0
oGameState.value-=10
ok
ogame.remove(oself.nindex)
checkgameover(oGame)
ok
}
}
}
ok
}
}
next
text {
size = 30
file = "fonts/pirulen.ttf"
text = "Destroy All Enemies!"
nstep = 3
color = GE_COLOR_GREEN
x = 100 y=50
direction = ge_direction_incvertical
point = 500
}
text {
animate = false
point = 400
size = 30
file = "fonts/pirulen.ttf"
text = "Score : " + oGameState.score
x = 500 y=10
state = func oGame,oSelf { oSelf { text = "Score : " + oGameState.score } }
}
text {
animate = false
point = 400
size = 30
file = "fonts/pirulen.ttf"
text = "Energy : " + oGameState.value
x = 500 y=50
state = func oGame,oSelf { oSelf { text = "Energy : " + oGameState.value } }
}
text {
animate = false
point = 400
size = 30
file = "fonts/pirulen.ttf"
text = "Level : " + oGameState.level
x = 500 y=90
}
}
45.27. Stars Fighter Game 358

10. Ring Documentation, Release 1.2
func checkwin ogame
if oGameState.gameresult return ok
if oGameState.enemies = 0
oGameState.gameresult = true
oGame {
if oGameState.level < 30
text {
point = 400
size = 30
file = "fonts/pirulen.ttf"
text = "Level Completed!"
nStep = 3
x = 500 y=10
state = func ogame,oself {
if oself.y >= 400
ogame.shutdown = true
oGameState.level++
oGameState.enemies = oGameState.level
oGameState.gameresult = false
ok
}
}
else
text {
point = 400
size = 30
nStep = 3
file = "fonts/pirulen.ttf"
text = "You Win !!!"
x = 500 y=10
state = func ogame,oself {
if oself.y >= 400
ogame.shutdown = true
oGameState.value = 0
ok
}
}
ok
}
ok
func checkgameover ogame
if oGameState.gameresult return ok
if oGameState.value <= 0
oGameState.gameresult = true
oGame {
text {
point = 400
size = 30
nStep = 3
file = "fonts/pirulen.ttf"
text = "Game Over !!!"
x = 500 y=10
state = func ogame,oself {
if oself.y >= 400
ogame.shutdown = true
ok
45.27. Stars Fighter Game 359