[WIP]LuaPhysics: Demo

[psp-freak222]

I was bored one day and made a small 2d physics demo for the psp.
there is only one bug:The box moves faster and faster rather than slower and slower(like it should be) anyway, I need Lua coders to help me develop it into a 2d physics playground.

if any one would like to help PM me.

[xpack]

What exactly are you making

[psp-freak222]

Originally Posted by xpack

What exactly are you making

A 2d Physics playground For the PSP.

[michaelp]

what's physics?

even after that, i still don't really get it

[Mister Chief]

Physics: The science of matter and energy and their interactions.

[xpack]

Have you tried the program out...pretty cool the thing it does but he said he having a problem slowing it down, I haven't really looked at it but yeah
-= Double Post =-

System.usbDiskModeActivate()
object = Image.load("tux.png")
 posx = 240
 posy = 136
 weight = 0.6
 velx = 1
 vely = 3 


while true do
screen:clear()
pad=Controls.read()
 White = Color.new(255,255,255)
 oldx = posx
 oldy = posy
 posx = posx - velx
 posy = posy - vely
 velx = velx - weight 
 vely = vely - weight
 if posx > 480 or posx < 0 then
	velx = -velx 
	posx = oldx
weight = weight + .6 
 end
 if posy > 272 or  posy < 0 then 
	vely = -vely
        posy = oldy
weight = weight + .6
 end
 screen:blit(posx,posy,object)
if pad:r() then break end
screen.flip()

screen.waitVblankStart()
end

I put this and i did something REALLY weird

[nataku92]

Well since the velocity can be negative, when you subtract the weight from it, it'll become even more negative (meaning faster right motion). So an easy fix would be to check if the velocity is negative; in that case, just add the weight instead (and clamp it to 0);

[xpack]

System.usbDiskModeActivate()
object = Image.load("tux.png")
 posx = 240
 posy = 136
 weight = 0.6
 velx = 1
 vely = 3 


while true do
screen:clear()
pad=Controls.read()
 White = Color.new(255,255,255)
 oldx = posx
 oldy = posy
 posx = posx - velx
 posy = posy - vely
 velx = velx - weight 
 vely = vely - weight
 if posx > 480 or posx < 0 then
	velx = -velx 
	posx = oldx
if velx < 0 then weight = weight + .1 end
 end
 if posy > 272 or  posy < 0 then 
	vely = -vely
        posy = oldy
if vely < 0 then weight = weight + .1 end
 end
 screen:blit(posx,posy,object)
if pad:r() then break end
screen.flip()

screen.waitVblankStart()
end

This way it does a really cool affect but I't not what he wanted

System.usbDiskModeActivate()
object = Image.load("tux.png")
 posx = 240
 posy = 136
 weight = 0.6
 velx = 1
 vely = 3 


while true do
screen:clear()
pad=Controls.read()
 White = Color.new(255,255,255)
 oldx = posx
 oldy = posy
 posx = posx - velx
 posy = posy - vely
 velx = velx - weight 
 vely = vely - weight
 if posx > 480 or posx < 0 then
	velx = -velx 
	posx = oldx
if velx < 0 then velx = velx + weight end
 end
 if posy > 272 or  posy < 0 then 
	vely = -vely
        posy = oldy
if vely < 0 then vely = vely + weight end
 end
 screen:blit(posx,posy,object)
if pad:r() then break end
screen.flip()

screen.waitVblankStart()
end

This way it speeds up but eventually stays at a constant rate and continues that way

@nataku92 - I dont really understand what you mean

[nataku92]

I basically meant what you did in your second example.

[xpack]

Yeah I thought that but all it does is speed up and stay at a constant rate of speed after a while.

[nataku92]

Bleh didn't look at your code closely enough. I meant add the weight if it's positive, and subtract it if it's positive:

Spoiler for code:

System.usbDiskModeActivate()
object = Image.load("tux.png")
 posx = 240
 posy = 136
 weight = 0.6
 velx = 1
 vely = 3 


while true do
screen:clear()
pad=Controls.read()
 White = Color.new(255,255,255)
 oldx = posx
 oldy = posy
 posx = posx - velx
 posy = posy - vely
 if velx > 0 then 
 	velx = velx - weight 
 	if velx < 0 then velx = 0 end
 end
 if vely > 0 then
 	vely = vely - weight 
 	if vely < 0 then vely = 0 end
 end
 if velx < 0 then 
 	velx = velx + weight 
 	if velx > 0 then velx = 0 end
 end
 if vely < 0 then
 	vely = vely + weight 
 	if vely > 0 then vely = 0 end
 end
 if posx > 480 or posx < 0 then
	velx = -velx 
	posx = oldx
 end
 if posy > 272 or  posy < 0 then 
	vely = -vely
        posy = oldy

 end
 screen:blit(posx,posy,object)
if pad:r() then break end
screen.flip()

screen.waitVblankStart()
end

Of course, acceleration might be a more suitable variable instead of weight.

[xpack]

This doesn't do anything it just shows up in place and goes up like 5 pixel then just stays in place

[nataku92]

And that means that it's slowing down...and stopping. Just make the starting velocities larger or the weight smaller (or both), and you'll it'll give better results.