need some physics here...

[isotope11]

Would someone have code that emulates projectile motion.
This is what I've got:

Shape1 - the projectile

The variables are:

Velocity - the muzzle velocity
Angle - the angle in which the projectile is fired

Other variables are:

Height - how high is the projectile in the specific time
Range - how far is the projectile from the point of origin

I know all these variables, but I just forgot the formula. Please help me.

[Dököll]

Would someone have code that emulates projectile motion.
This is what I've got:

Shape1 - the projectile

The variables are:

Velocity - the muzzle velocity
Angle - the angle in which the projectile is fired

Other variables are:

Height - how high is the projectile in the specific time
Range - how far is the projectile from the point of origin

I know all these variables, but I just forgot the formula. Please help me.

Hello, isotope11!

Seems like you have work cut out...

Is this C++?

You may need to figure outhow to solve this manually firsthand before loading into a program. Perhaps builing a pseudocode, after you have mastered a manual result can help.

How's that for a deal?

Dököll

[danp129]

If you know Quick Basic by chance I bet there's an example in Gorillas.bas... or was it Gorilla.bas :) Search the net for it.

[Killer42]

Surely you just apply the current velocity, and adjust for 9.8 metres-per-second-per-second acceleration downward.

I do remember two of the three fundamental equations of motion we learned in physics at high school...

v = u + at
s = ut + ½at2 (don't know how to superscript the "2").

v = final velocity
u = initial velocity
a = acceleration
t = time
s = distance (actually "displaceme nt" I think)


By the way, since it has always been one of the most basic (no pun intended) functions to which computers have been applied, perhaps you could try looking up "ballistics " somewhere like Wikipedia.

[brazel]

Good day!

try this link

http://members.home.net/theluckyleper

[Killer42]

That link just takes one to the home.net home page.

[brazel]

Good day!

Sir

Sorry that link, I think that link is that link that I get b4.

[brazel]

[CODE=vb]'************** *************** *************** *****
' Basic gravity demo! Feel free to modify this
' code, steal it, etc. I don't give a crap! It's
' a falling circle for crying out loud :)
'
' - Lucky
' Lucky's VB Gaming Site
' http://members.home.net/theluckyleper
'************** *************** *************** *****

Option Explicit

'The gettickcount API delcaration
Private Declare Function GetTickCount Lib "kernel32" () As Long

Const PI = 3.14159 'Mmmm.. Pi
Const ORBIT_GRAVITY = 1000 'Acceleration due to gravity (during the "orbit" sequence)
Const FALL_GRAVITY = 0.1 'Acceleration due to gravity (during the "fall" sequence)
Const OBJECT_RADIUS = 10 'How FALL is our "ball"?

Const ORBIT_PLN_RADIU S = 15 'How big is our planet during an "orbit" sequence?
Const ORBIT_PLN_X = 200 'X-Coordinate of the planet during an "orbit"
Const ORBIT_PLN_Y = 200 'Y-Coordinate of the planet during an "orbit"
Const ORBIT_OBJ_X = 280 'Starting X-Coord of our object during an "orbit"
Const ORBIT_OBJ_Y = 220 'Starting Y-Coord of our object during an "orbit"
Const ORBIT_OBJ_SPEED = 4 'Starting speed during an "orbit"
Const ORBIT_OBJ_HEADI NG = 0 'Starting heading during an "orbit"

Const FALL_PLN_RADIUS = 500 'How big is our planet during a "fall" sequence?
Const FALL_PLN_X = 200 'X-Coordinate of the planet during a "fall"
Const FALL_PLN_Y = 600 'Y-Coordinate of the planet during a "fall"
Const FALL_OBJ_X = 375 'Starting X-Coord of our object during a "fall"
Const FALL_OBJ_Y = 345 'Starting Y-Coord of our object during a "fall"
Const FALL_OBJ_SPEED = 7 'Starting speed during a "fall"
Const FALL_OBJ_HEADIN G = 15 * PI / 8 'Starting heading during a "fall"

Const MS_DELAY = 25 'Milliseconds per frame (25 = 40 frames per second)

Dim mlngTimer As Long 'Holds system time since last frame was displayed
Dim msngHeading As Single 'Current direction in which object is moving
Dim msngSpeed As Single 'Current speed with which object is moving
Dim msngObjX As Single 'Current X coordinate of object within form
Dim msngObjY As Single 'Current Y coordinate of object within form
Dim mblnRunning As Boolean 'Is the render loop running?
Dim mblnOrbit As Boolean 'Are we orbiting?
Dim mblnFall As Boolean '..or are we falling?

Private Sub Form_Load()

'Initialize the variables
mlngTimer = GetTickCount()
mblnRunning = True
mblnOrbit = False
mblnFall = False
shpObject.Width = OBJECT_RADIUS
shpObject.Heigh t = OBJECT_RADIUS

'Display the form
frmGravity.Show

'Start the render loop
Do While mblnRunning
'Check if we've waited for the appropriate number of milliseconds
If mlngTimer + MS_DELAY <= GetTickCount() Then
mlngTimer = GetTickCount() 'Reset the timer variable
If mblnOrbit Then Physics_Orbit 'Make the object orbit
If mblnFall Then Physics_Fall 'Make the object fall
If mblnOrbit Or mblnFall Then DrawObject 'Draw the object
End If
'Allow other events to occur
DoEvents
Loop

End Sub

Private Sub cmdOrbit_Click( )

'Set up our booleans
mblnOrbit = True
mblnFall = False

'Place the planet
shpPlanet.Width = ORBIT_PLN_RADIU S
shpPlanet.Heigh t = ORBIT_PLN_RADIU S
shpPlanet.Left = ORBIT_PLN_X - shpPlanet.Width / 2
shpPlanet.Top = ORBIT_PLN_Y - shpPlanet.Heigh t / 2

'Place the object
msngSpeed = ORBIT_OBJ_SPEED
msngHeading = ORBIT_OBJ_HEADI NG
msngObjX = ORBIT_OBJ_X
msngObjY = ORBIT_OBJ_Y

End Sub

Private Sub cmdFall_Click()

'Set up our booleans
mblnOrbit = False
mblnFall = True

'Place the planet
shpPlanet.Width = FALL_PLN_RADIUS
shpPlanet.Heigh t = FALL_PLN_RADIUS
shpPlanet.Left = FALL_PLN_X - shpPlanet.Width / 2
shpPlanet.Top = FALL_PLN_Y - shpPlanet.Heigh t / 2

'Place the object
msngSpeed = FALL_OBJ_SPEED
msngHeading = FALL_OBJ_HEADIN G
msngObjX = FALL_OBJ_X
msngObjY = FALL_OBJ_Y

End Sub

Private Sub DrawObject()

'Move the object (according to its speed and heading)
msngObjX = msngObjX + msngSpeed * Sin(msngHeading )
msngObjY = msngObjY - msngSpeed * Cos(msngHeading )

'Display the object
shpObject.Left = msngObjX - OBJECT_RADIUS / 2
shpObject.Top = msngObjY - OBJECT_RADIUS / 2

End Sub

Private Sub Physics_Orbit()

Dim sngXComp As Single 'Resultant X and Y components
Dim sngYComp As Single
Dim sngPlnX As Single 'X Distance to planet
Dim sngPlnY As Single 'Y Distance to planet
Dim sngDist As Single 'The linear distance to planet
Dim sngGravDir As Single 'In which direction is gravity acting (towards the planet!)

'Find the distance to planet
sngPlnX = ORBIT_PLN_X - msngObjX
sngPlnY = msngObjY - ORBIT_PLN_Y
sngDist = Sqr(sngPlnX ^ 2 + sngPlnY ^ 2)

'Calculate the gravity direction, and adjust for arctangent by adding Pi if necessary
If sngPlnY > 0 Then sngGravDir = Atn(sngPlnX / sngPlnY)
If sngPlnY < 0 Then sngGravDir = Atn(sngPlnX / sngPlnY) + PI

'Find the components
sngXComp = msngSpeed * Sin(msngHeading ) + (ORBIT_GRAVITY / (sngDist ^ 2)) * Sin(sngGravDir)
sngYComp = msngSpeed * Cos(msngHeading ) + (ORBIT_GRAVITY / (sngDist ^ 2)) * Cos(sngGravDir)

'Determine the resultant speed
msngSpeed = Sqr(sngXComp ^ 2 + sngYComp ^ 2)

'Calculate the resultant heading, and adjust for arctangent by adding Pi if necessary
If sngYComp > 0 Then msngHeading = Atn(sngXComp / sngYComp)
If sngYComp < 0 Then msngHeading = Atn(sngXComp / sngYComp) + PI

End Sub

Private Sub Physics_Fall()

Dim sngXComp As Single 'Resultant X and Y components
Dim sngYComp As Single

'Find the components
sngXComp = Sin(msngHeading ) * msngSpeed
sngYComp = Cos(msngHeading ) * msngSpeed - FALL_GRAVITY 'Don't forget to apply gravity straight down!

'Determine the resultant speed
msngSpeed = Sqr(sngXComp ^ 2 + sngYComp ^ 2)

'Calculate the resultant heading, and adjust for arctangent by adding Pi if necessary
If sngYComp > 0 Then msngHeading = Atn(sngXComp / sngYComp)
If sngYComp < 0 Then msngHeading = Atn(sngXComp / sngYComp) + PI

'Stop the ball when it hits the "ground"
If msngObjY > FALL_OBJ_Y Then msngSpeed = 0

End Sub

Private Sub Form_Unload(Can cel As Integer)

'Terminate the render loop
mblnRunning = False

End Sub[/CODE]

[isotope11]

I have QuickBasic, but it is installed in my old CPU.

[isotope11]

It is s = ut + ½at ^ 2

[Killer42]

It is s = ut + ½at ^ 2

Yeah, I suppose I could have written it as something like ½a(tt), too. I'm just used to using the superscripted "2" to represent the square.

By the way, do you remember the third? There were three fundamental equations that we used back in high school physics to calculate all this stuff, but I can only ever recall two of them.

Ahah!

How does this look... s = ut + ½at²

[JonLT]

this might help

newPosition = oldPosition + (Velocity * dt)
Velocity += (Force * (1.0/Mass)) *dt

the positions, velocity and force are vectors (x,y,z) so be sure to use the right math

[Killer42]

this might help

newPosition = oldPosition + (Velocity * dt)
Velocity += (Force * (1.0/Mass)) *dt

the positions, velocity and force are vectors (x,y,z) so be sure to use the right math

This thread is a couple of months old now, so I'd guess the issue would have been resolved by now. isotope11, if you're still around, how did it turn out?