3057 posts
United States of America
Posted 19 January 2015 - 04:17 AM
As the title says, I've been screwing with "gravity". Lots of fun math in that, force vectors and such. Currently I'm having a little problem where I should hit the "planet", but never do (actually if it's small enough you can force your way to it with the controls, but…).
Plus, I'm getting acceleration from who-knows-where, probably the planet but not in the direction of the planet.
It's a little hard to describe, just run the code and it'll be fairly obvious.
Controls: arrow keys
PS: Anyone know a good way to generate an infinite map? My attempts have been… not so great. If you feel interested in contributing, reply here or PM me.
Plus, I'm getting acceleration from who-knows-where, probably the planet but not in the direction of the planet.
It's a little hard to describe, just run the code and it'll be fairly obvious.
Controls: arrow keys
Spoiler
local function radians( x1, y1, x2, y2 )
return math.atan2( x2-x1, (y2-y1) ) --#might add 0.66 compensate for strange CC pixels
end
local function getXY( r, mag )
return mag * math.cos( r ), mag * math.sin( r )
end
local function fGrav( m1, x1, y1, m2, x2, y2 )
return (m1*m2)/math.sqrt((x2 - x1)^2 - ((y2 - y1)*0.66)^2)^2 --#might add0.66 compensate for strange CC pixels
end
local function mass( r )
return math.pi * r^2
end
local maxx, maxy = term.getSize()
local gravPoints = {}
gravPoints[ #gravPoints + 1 ] = { x = maxx, y = math.random( 1, maxy ), magnitude = math.random( 2, 4 ) }
--Thanks to TheOriginalBIT for this circle code
local function drawCircle( centerX, centerY, radius, col, solid )
solid = solid or false
local isAdvanced = term.isColor and term.isColor()
local char = isAdvanced and " " or "|"
if isAdvanced then term.setBackgroundColor( col ) end
local radStep = 1/(1.5*radius)
for angle = 1, math.pi+radStep, radStep do
local pX = math.cos( angle ) * radius * 1.5
local pY = math.sin( angle ) * radius
if solid then
local chord = 2*math.abs(pX)
term.setCursorPos( centerX - chord/2, centerY - pY )
write( char:rep( chord ) )
term.setCursorPos( centerX - chord/2, centerY + pY )
write( char:rep( chord ) )
else
for i=-1,1,2 do
for j=-1,1,2 do
term.setCursorPos( centerX + i*pX, centerY + j*pY )
write( char )
end
end
end
end
end
local object = { x = 1, y = 1, mag = 0, angle = 0 }
local function draw()
term.setBackgroundColor( colors.lightGray )
term.clear()
--draw gravity points
for _, point in pairs( gravPoints ) do
drawCircle( point.x - object.x, point.y - object.y, point.magnitude, colors.gray, true )
end
--draw player
term.setBackgroundColor( colors.green )
term.setCursorPos( maxx / 2, maxy / 2 )
term.write( " " )
term.setBackgroundColor( colors.lightGray )
term.setTextColor( colors.black )
term.setCursorPos( 1, 1 )
term.write( "Speed: " .. tostring(object.mag):match( "%d+%.%d%d" ) )
term.setCursorPos( 1, 2 )
term.write( "X: " .. object.x )
term.setCursorPos( 1, 3 )
term.write( "Y: " .. object.y )
end
local tControls = {}
local id = os.startTimer( 0.1 )
while true do
local event = { os.pullEvent() }
if event[ 1 ] == "timer" and event[ 2 ] == id then
--calc movement on object
local vx, vy = getXY( object.angle, object.mag )
id = os.startTimer( 0.1 )
for _, point in pairs( gravPoints ) do
local mag = fGrav( mass( 1 ) * 2, object.x, object.y, mass( point.magnitude ) * 2, point.x, point.y )
local angle = radians( object.x, object.y, point.x, point.y )
local x, y = getXY( angle, mag )
vx = vx + x
vy = vy + y
end
--add player forces
if tControls[ keys.up ] then
vy = vy - 0.66
end
if tControls[ keys.down ] then
vy = vy + 0.66
end
if tControls[ keys.right ] then
vx = vx + 1
end
if tControls[ keys.left ] then
vx = vx - 1
end
tControls = {}
object.x = object.x + vx
object.y = object.y + vy
object.angle = math.atan2( vx, vy )
object.mag = math.sqrt(vx^2 + vy^2)
draw()
elseif event[ 1 ] == "key" then
tControls[ event[ 2 ] ] = true
end
end
PS: Anyone know a good way to generate an infinite map? My attempts have been… not so great. If you feel interested in contributing, reply here or PM me.
