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@raingloom
Last active April 25, 2016 01:19
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local sqrt, sin, cos = math.sqrt, math.sin, math.cos
local pi = math.pi
local r1, r2 = 0 , 1.0
local g1, g2 = -sqrt( 3 )/2, -0.5
local b1, b2 = sqrt( 3 )/2, -0.5
--[[--
@param h a real number between 0 and 2*pi
@param s a real number between 0 and 1
@param v a real number between 0 and 1
@return r g b a
]]
local function HSVToRGB( h, s, v, a )
h=h+pi/2--because the r vector is up
local r, g, b = 1, 1, 1
local h1, h2 = cos( h ), sin( h )
--hue
r = h1*r1 + h2*r2
g = h1*g1 + h2*g2
b = h1*b1 + h2*b2
--saturation
r = r + (1-r)*s
g = g + (1-g)*s
b = b + (1-b)*s
r,g,b = r*v, g*v, b*v
return r*255, g*255, b*255, (a or 1) * 255
end
local W,H
local testCanvas
local sqrt, sin, cos, min, max = math.sqrt, math.sin, math.cos, math.min, math.max
local pi = math.pi
local r1, r2 = 0 , 1.0
local g1, g2 = -sqrt( 3 )/2, -0.5
local b1, b2 = sqrt( 3 )/2, -0.5
--[[--
@param h a real number between 0 and 2*pi
@param s a real number between 0 and 1
@param v a real number between 0 and 1
]]
local function HSVToRGB( h, s, v, a )
h=h+pi/2--because the r vector is up
local r, g, b = 1, 1, 1
local h1, h2 = cos( h ), sin( h )
--hue
r = h1*r1 + h2*r2
g = h1*g1 + h2*g2
b = h1*b1 + h2*b2
--saturation
r = r + (1-r)*s
g = g + (1-g)*s
b = b + (1-b)*s
r,g,b = r*v, g*v, b*v
return r*255, g*255, b*255, (a or 1) * 255
end
--[[
for i = 0, 360, 15 do
print( i, HSVToRGB( pi*2*(i/360)))
end
--os.exit( true, true )
--]]
local function drawHSVTest( canvas, v )
local _c = love.graphics.getCanvas()
love.graphics.setCanvas( canvas )
local W,H = canvas:getDimensions()
print( W,H )
local setColor, points = love.graphics.setColor, love.graphics.points
for x = 0, W do
for y = 0, H do
setColor( HSVToRGB( 2*pi*(x/W), y/H, v ) )
points(x,y)
end
end
love.graphics.setCanvas( _c )
end
function love.load()
love.resize()
end
function love.resize()
W,H = love.graphics.getDimensions()
testCanvas = love.graphics.newCanvas( W,H )
drawHSVTest( testCanvas, 1 )
end
function love.draw()
love.graphics.setColor( 255, 255, 255, 255 )
love.graphics.setBlendMode( "alpha", "premultiplied" )
love.graphics.draw( testCanvas )
end
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