// An example of using closures
func main() {
func() {
const (
speed = 90.0
friction = 0.98
)
var (
spr sprite.Sprite
fnt *font.Font
par *particle.ParticleSystem
snd *Effect
x = 100.0
y = 100.0
dx = 0.0
dy = 0.0
)
hge := New()
hge.SetState(LOGFILE, "tutorial03.log")
hge.SetState(TITLE, "HGE Tutorial 03 - Using helper classes")
hge.SetState(FPS, 100)
hge.SetState(WINDOWED, true)
hge.SetState(SCREENWIDTH, 800)
hge.SetState(SCREENHEIGHT, 600)
hge.SetState(SCREENBPP, 32)
hge.SetState(FRAMEFUNC, func() int {
dt := float64(Delta())
boom := func() {
pan := int((x - 400) / 4)
pitch := (dx*dx+dy*dy)*0.0005 + 0.2
snd.PlayEx(100, pan, pitch)
}
// Process keys
if NewKey(K_ESCAPE).State() {
return 1
}
if NewKey(K_LEFT).State() {
dx -= speed * dt
}
if NewKey(K_RIGHT).State() {
dx += speed * dt
}
if NewKey(K_UP).State() {
dy -= speed * dt
}
if NewKey(K_DOWN).State() {
dy += speed * dt
}
// Do some movement calculations and collision detection
dx *= friction
dy *= friction
x += dx
y += dy
if x > 784 {
x = 784 - (x - 784)
dx = -dx
boom()
}
if x < 16 {
x = 16 + 16 - x
dx = -dx
boom()
}
if y > 584 {
y = 584 - (y - 584)
dy = -dy
boom()
}
if y < 16 {
y = 16 + 16 - y
dy = -dy
boom()
}
// Update particle system
par.Info.Emission = (int)(dx*dx+dy*dy) * 2
par.MoveTo(x, y)
par.Update(dt)
return 0
})
hge.SetState(RENDERFUNC, func() int {
BeginScene()
Clear(0)
par.Render()
spr.Render(x, y)
fnt.Printf(5, 5, font.TEXT_LEFT, "dt:%.3f\nFPS:%d (constant)", Delta(), GetFPS())
EndScene()
return 0
})
if err := hge.Initiate(); err == nil {
defer hge.Shutdown()
snd = NewEffect("menu.ogg")
tex := LoadTexture("particles.png")
if snd == nil || tex == nil {
fmt.Printf("Error: Can't load one of the following files:\nmenu.ogg, particles.png, font1.fnt, font1.png, trail.psi\n")
return
}
spr = sprite.New(tex, 96, 64, 32, 32)
spr.SetColor(0xFFFFA000)
spr.SetHotSpot(16, 16)
if fnt = font.New("font1.fnt"); fnt == nil {
fmt.Println("Error loading font1.fnt")
return
}
spt := sprite.New(tex, 32, 32, 32, 32)
spt.SetBlendMode(BLEND_COLORMUL | BLEND_ALPHAADD | BLEND_NOZWRITE)
spt.SetHotSpot(16, 16)
par = particle.New("trail.psi", spt)
if par == nil {
fmt.Println("Error loading trail.psi")
return
}
par.Fire()
hge.Start()
}
}()
for i := 0; i < 10; i++ {
fmt.Println("Sleeping")
time.Sleep(1 * time.Second)
runtime.GC()
}
}
