calculating angles

i am making a "tank" game and i need help making the "bullet" fired from the tank go at a angle and power that has been entered by the player. i dont want it going in a straight line i want it to go up then back down, but i cant figuer how to do that.

any help would be greatly apreciated. thank you

i think i have to use the parabola formula but i forgot the formula. it was something like this but it wont work for me.

sub command1_click()
form1.scale (0,500)-(1000,-500)
for x = 0 to 1000
pset (x , sin(x ^ 2)
next x
end sub

i thought that is how you draw a parabola but it didn't work for me. any help would be greatly apreciated.

[Aaron Young]

I haven't used Newtonian Mechanics for a few years, but I think these are the equations you are looking for, you'll need to tweak all the variables to get them the way you want them..

In a Form with a Large Picturebox, 2 Textboxes and a Command Button..

Private Sub Command1_Click()
Dim pX As Single 'X Dist
Dim pY As Single 'Y Dist
Dim pT As Single 'Time
Dim pUy As Single 'Initial Y Velocity
Dim pUx As Single 'Initial X Velocity
Dim pG As Single 'Gravity
Dim pW As Single 'Wind Resistance
Dim pV As Single 'Velocity
Dim lX As Single
Dim lY As Single

pW = 0 'Wind Resistence
pG = -8.13 'Gravity
pV = Val(txtSpeed) / 5 'Get Entered Speed
'Calculate X & Y Initial Velocity
pUy = Round(Sin(Val(txtAngle) * (3.14 / 180)), 2) * pV
pUx = Round(Cos(Val(txtAngle) * (3.14 / 180)), 2) * pV
Picture1.AutoRedraw = True
Do
pT = pT + 0.01 'Increment Time
pY = pY + (pUy * pT) + ((pG * (pT ^ 2)) / 2) 'Distance along the Y Axis
pX = pX + (pUx * pT) + ((pW * (pT ^ 2)) / 2) 'Distance along the X Axis
Picture1.PSet (lX, Picture1.ScaleHeight - lY), Picture1.BackColor
Picture1.PSet (pX, Picture1.ScaleHeight - pY), vbBlack
lX = pX
lY = pY
DoEvents
Loop While pY > 0 And pX < Picture1.ScaleWidth
End Sub


------------------
Aaron Young
Analyst Programmer
aarony@redwingsoftware.com
adyoung@win.bright.net

ALL i can say is :
DAAAAAAMMMMMMMMMMMMEEEEEEEEEEEEE !!!!

Dude where did you get that info my god ...
Is there a way of learning this things ?

aaron your the man! i have been slacking off in math too much =).

thanx buddy

aaron if you could, can you please explain how the code works? i dont understand why you need time and some other things to calculate distance and angle. i would be so greatfull if you can explain how it works.

also the variable pV doesn't work because it is a code word so i changed it to something else, so it works fine. and how do i make the pset command start from my "tank" which is actually an image box? because the code works fine but it doesn't shoot from my tank =).

thanx again, i really owe you one.

well i understand the code now so you dont have to explain. i also got it to fire from my tank and not the corner of the picturebox.

but one more thing, how do i make the trail keep going untill it hits land? my land isn't a flat surface, it has been drawn using the sin command. so i dont want the trail stopping when y is less then 0 i want to it keep going untill it hits ground.

if you want i can send my source to you if it will make it easier for you. thank you so much

[Aaron Young]

The easiest way would be to check the Pixel Color at the "Bullets" Coords using the Point Method, if it's a Certain Color, (The Color of the Ground), it's Landed.

------------------
Aaron Young
Analyst Programmer
aarony@redwingsoftware.com
adyoung@win.bright.net

thanx aaron, again you figuered out how to solve someones problem. what would us peons ever do without you?