Sprites

[Darkjester]

As i hardly ever use teh sprite engine, i am attempting to utilize it(i usually just use opengl which i can do this in)
i have 2 questions
1) how can i smooth the movement(im sure you will know what im trying to do once you run it
2)how to keep the sprites from going back to origin of screen(does that make sense)
its 2 20 am and im half asleep anyway -darkjester

struc stank
   dim pos(1)
   dim turret
   dim tank
   dim ang
   dim old(2)
endstruc

dim Stank tank

tank.turret = Newsprite(LoadTex("data\turret.png"))
tank.tank = newsprite(Loadtex("data\tank.png"))
dim crosshair = newsprite(loadtex("data\crosshair.png"))                                                


'turret setup for tank
bindsprite(tank.turret)
sprsetangle(-90)
sprsetsize(25,25)
sprsetpos(320,240)
'tankbase setup for tank
bindsprite(tank.tank)
sprsetangle(-90)
sprsetsize(50,30)
sprsetpos(320,240)

declare sub updatetank()

while true
   if Scankeydown(vk_left) then
       tank.old(2) = tank.ang
       tank.ang = tank.ang - 1
       updatetank()
   endif
   if Scankeydown(vk_right) then
       tank.old(2) = tank.ang
       tank.ang = tank.ang + 1
       updatetank()
   endif
   If Scankeydown(vk_up) then
       tank.old(0) = tank.pos(0) : tank.old(1) = tank.pos(1)
       tank.pos(0) = tank.pos(0) + cosd (tank.ang) * 2
       tank.pos(1) = tank.pos(1) + sind (tank.ang) * 2
       updatetank()
   endif
   If Scankeydown(vk_down) then
       tank.old(0) = tank.pos(0) : tank.old(1) = tank.pos(1)
       tank.pos(0) = tank.pos(0) - cosd (tank.ang) * 2
       tank.pos(1) = tank.pos(1) - sind (tank.ang) * 2
       updatetank()
   endif

wend

sub Updatetank()
   bindsprite(tank.tank)
   sprsetangle(tank.ang)
   sprsetpos(tank.pos(0), tank.pos(1))
   bindsprite(tank.turret)
   sprsetangle(tank.ang)
   sprsetpos(tank.pos(0), tank.pos(1))
endsub

[Nicky Peter Hollyoake]

Oh my God! that was frustrating!

OK!

1) Your moving ain't smooth because your using an integer! Use a float.

eg:

struc stank
    dim pos(1) as double
    dim turret
    dim tank
    dim ang
    dim old(2)
endstruc

2) Your sprite doesn't stay in the centre because of this:

'tankbase setup for tank
bindsprite(tank.tank)
sprsetangle(-90)
sprsetsize(50,30)
sprsetpos(320,240)

You need to make sure you put the values in your structure varible before the main loop.

Something like ...

Tank.Pos(0) = 320
Tank.Pos(1) = 240
Tank.Ang = -90

etc, etc...

- Nicky

[shadow008]

why not use SprSetVel(x,y) for movement instead, that seems to move sprites pretty smoothly

[Darkjester]

Thanks for the Help guys -darkjester

[Adam]

SprSetvel() is very handy indeed but with the current code it would be easier to just fix it up a bit
first off you want to set the position variable to the current position of the sprite so you don't have it jump to the top corner. also as nicky said, use a floating type variable (sine and cosine only range between -1 and 1 so you will lose a lot by not taking advantage of everything between) and the result is nice and smooth

EDIT:\
another nice thing to do that i forgot to add, set tank.ang to -90

[Darkjester]

Here is my fix ;D im quite pleased with the outcome

struc stank
dim pos(1) as double
dim turret
dim tank
dim ang as double
dim old(2)
endstruc

dim Stank tank
tank.pos(0) = 320
tank.pos(1) = 240
tank.ang = -90

tank.turret = Newsprite(LoadTex("data\turret.png"))
tank.tank = newsprite(Loadtex("data\tank.png"))
dim crosshair = newsprite(loadtex("data\crosshair.png"))

textmode(text_buffered)

'turret setup for tank
bindsprite(tank.turret)
sprsetangle(tank.ang)
sprsetsize(25,25)
sprsetpos(tank.pos(0),tank.pos(1))
'tankbase setup for tank
bindsprite(tank.tank)
sprsetangle(tank.ang)
sprsetsize(50,30)
sprsetpos(tank.pos(0),tank.pos(1))

declare sub updatetank()

while true
if Scankeydown(vk_left) then
   tank.old(2) = tank.ang
   tank.ang = tank.ang - 1
   updatetank()
endif
if Scankeydown(vk_right) then
   tank.old(2) = tank.ang
   tank.ang = tank.ang + 1
   updatetank()
endif
If Scankeydown(vk_up) then
   tank.old(0) = tank.pos(0) : tank.old(1) = tank.pos(1)
   tank.pos(0) = tank.pos(0) + cosd (tank.ang) * 2
   tank.pos(1) = tank.pos(1) + sind (tank.ang) * 2
   updatetank()
endif
If Scankeydown(vk_down) then
   tank.old(0) = tank.pos(0) : tank.old(1) = tank.pos(1)
   tank.pos(0) = tank.pos(0) - cosd (tank.ang) * 2
   tank.pos(1) = tank.pos(1) - sind (tank.ang) * 2
   updatetank()
endif
drawtext()
wend

sub Updatetank()
   bindsprite(tank.tank)
   sprsetangle(tank.ang)
   sprsetpos(tank.pos(0), tank.pos(1))
   bindsprite(tank.turret)
   sprsetangle(tank.ang)
   sprsetpos(tank.pos(0), tank.pos(1))
endsub

[Darkjester]

How can I use the letter keys, i thought it was keydown("a") or something of similar nature? it doesnt appear to be doing anything. and can i cast an float into an integer in basic4gl?

[shadow008]

Nov 25, 2009 13:38:23 GMT -5 Darkjester said:

How can I use the letter keys, i thought it was keydown("a") or something of similar nature? it doesnt appear to be doing anything. and can i cast an float into an integer in basic4gl?

ehrm:

keydown("A")

your welcome!

also yeah just have an integer equal to the float

eg.

dim x#,y

y = x#

y equals the nearest integer (0 < .5) - (.5 <= 1) of x

or INT command? (though it works weird)

[Darkjester]

Thnx for the Help Shadow, im pretty rusty programming wise and i forgot specifics of some things -darkjester