# Math

(Redirected from Category:Math)

Supported platforms:
Available since: Gideros 2011.6

### Description

math table holds most commonly used math functions and constants.

### Example

A nice example demonstrating various Gideros specific maths functions

```local myappwidth = application:getContentWidth()
local myappheight = application:getContentHeight()
application:setBackgroundColor(0x555555)

local pixel = Pixel.new(0xffffff, 1, 16, 16)
pixel:setAnchorPoint(0.5, 0.5)
pixel:setPosition(7*myappwidth/10, 5*myappheight/10)

local raycast = Shape.new()

-- circle
local p=Particles.new()
local circlepts={}
circlepts[#circlepts+1] = { -- 1st circle
x=128, y=128,
size=128,
color=0x0000ff,
id=#circlepts+1,
}
circlepts[#circlepts+1] = { -- 2nd circle
x=128*3, y=128,
size=128*1.5,
color=0x0000aa,
id=#circlepts+1,
}
circlepts[#circlepts+1] = { -- 3rd circle
x=128*2, y=128*3,
size=64,
color=0x000055,
id=#circlepts+1,
}

-- markers
local pedge = p:addParticles{ {x=0, y=0, size=5, color=0x0} }[1]
local pray = p:addParticles{ {x=0, y=0, size=5, color=0xffffff, alpha=1} }[1]
local pray2 = p:addParticles{ {x=0, y=0, size=5, color=0xaaaaaa, alpha=1} }[1]

local shapeid
local mouse={x=e.x, y=e.y}

-- reset all circles original colors
for i = 1, #circlepts do
p:setParticleColor(i, circlepts[i].color, 1)
end

-- gets the mouse nearest circle id
local nearestpoint, npdistance = math.nearest(mouse, circlepts)
shapeid=nearestpoint.id
-- highlights circle if mouse is close
if npdistance < circlepts[shapeid].radius + 48 then
p:setParticleColor(shapeid, 0xffff00, 1)
end

-- checks if mouse is inside circle
local inside = math.inside(mouse, nearestpoint)
if inside < 0 then
p:setParticleColor(shapeid, 0x00ff00, 1)
end

-- edge
local d = math.edge(mouse, nearestpoint)
p:setParticlePosition(pedge, d.x, d.y)

-- raycast
local r = math.raycast( -- origin, direction, shape
{x=mouse.x, y=mouse.y},
math.normalize({x=mouse.x-pixel:getX(), y=mouse.y-pixel:getY()}),
circlepts
)
if r[1] then
p:setParticlePosition(pray, r[1].point.x, r[1].point.y)
p:setParticleColor(pray, p:getParticleColor(pray), 1)
else
p:setParticleColor(pray, p:getParticleColor(pray), 0)
end
if r[2] then
p:setParticlePosition(pray2, r[2].point.x, r[2].point.y)
p:setParticleColor(pray2, p:getParticleColor(pray2), 1)
else
p:setParticleColor(pray2, p:getParticleColor(pray2), 0)
end
-- a line
raycast:clear()
raycast:setLineStyle(5, 0xffffff, 0.5)
raycast:beginPath()
raycast:moveTo(mouse.x, mouse.y)
raycast:lineTo(pixel:getX(), pixel:getY())
raycast:endPath()
end)
```

### Methods

math.abs returns absolute value of v
math.acos returns arc cosine value of v in radians
math.asin returns arc sine value of v in radians
math.atan returns arc tangent value of v in radians
math.atan2 returns arc tangent value of v1/v2 in radians
math.ceil returns smallest integer >= v
math.clamp returns a number between min and max, inclusive
math.cos returns cosine value of angle rad
math.cosh returns hyperbolic cosine of v
math.exp returns e^v
math.fft computes the discrete Fourier transform
math.floor returns largest integer <= v
math.fmod returns remainder of v1/v2 which is v1 - iV2 for some integer i
math.frexp returns mantissa [0.5,1) and exponent values of v
math.ifft computes the inverse discrete Fourier transform
math.ldexp returns v1*2^v2
math.log returns natural logarithm of v
math.log10 returns logarithm 10 of v
math.max returns maximum in a list of one or more values
math.min returns minimum in a list of one or more values
math.modf returns the integer and fractional values of a number
math.noise returns a perlin noise value
math.pow returns v1 raised to the power of v2
math.random returns random real [0,1-, integer [1,n] or real [1,u](with n=1-
math.randomseed sets seed for pseudo-random number generator
math.round returns integer with the smallest difference between it and the given number
math.sign returns sign of v
math.sin returns sine value of angle rad
math.sinh returns hyperbolic sine of v
math.sqrt returns square root of v
math.tan returns tangent value of angle rad
math.tanh returns hyperbolic tangent of v
vector vectors

### Gideros specific methods

math.length returns the length of a vector
math.cross returns the cross product of two vectors
math.dot returns the dot product of two vectors
math.distance returns the distance between two points
math.distances returns the distances between a point and a set of points
math.nearest returns the nearest point from a list
math.normalize normalize a vector
math.raycast returns intersections between a ray and a set of shapes
math.inside returns wether a point is inside a shape
math.edge returns the nearest point on the edge of a shape

### Constants

huge #INF
pi 3.1415926535898