Difference between revisions of "love.graphics.polygon"

(Draw rotated triangle)
(Draw rotated triangle)
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love.graphics.polygon(mode, -length/2, -width /2, -length/2, width /2, length/2, 0)
 
love.graphics.polygon(mode, -length/2, -width /2, -length/2, width /2, length/2, 0)
 
love.graphics.pop()  
 
love.graphics.pop()  
 +
end
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</source>
 +
 +
 +
=== Pixel-perfect [https://en.wikipedia.org/wiki/Hexadecagon Hexadecagon] ===
 +
For better result it can be used with "rough" line style and "nearest" canvas filter.
 +
<source lang="lua">
 +
function hexadecagon (mode, x, y, radius) -- same as [[love.graphics.circle|circle]]
 +
local w1, w2 = math.atan(0.21), math.atan(0.72) -- magic values
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local a = radius
 +
local b = radius*math.sin (w1)
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local c = radius*math.cos (w2)
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local d = radius*math.sin (w2)
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local vertices = {
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a, b,  c, d,  d, c,  b, a,
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-b, a, -d, c, -c, d, -a, b,
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-a,-b, -c,-d, -d,-c, -b,-a,
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b,-a,  d,-c,  c,-d,  a,-b}
 +
love.graphics.translate (x+0.5, y+0.5)
 +
love.graphics.polygon (mode, vertices)
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love.graphics.translate (-x-0.5, -y-0.5)
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end
 +
 +
canvas = love.graphics.newCanvas(width, height)
 +
canvas:setFilter("nearest", "nearest")
 +
love.graphics.setLineStyle("rough")
 +
love.graphics.setCanvas (canvas)
 +
love.graphics.setColor (0,1,0)
 +
hexadecagon ("line", 200, 100, 60)
 +
love.graphics.setCanvas ()
 +
 +
function love.draw()
 +
love.graphics.setColor (1,1,1)
 +
love.graphics.draw (canvas)
 
end
 
end
 
</source>
 
</source>

Revision as of 10:26, 14 June 2022

Available since LÖVE 0.4.0
This function is not supported in earlier versions.

Draw a polygon.

Following the mode argument, this function can accept multiple numeric arguments or a single table of numeric arguments. In either case the arguments are interpreted as alternating x and y coordinates of the polygon's vertices.

O.png When in fill mode, the polygon must be convex and simple or rendering artifacts may occur. love.math.triangulate and love.math.isConvex can be used in 0.9.0+.  


Function

Synopsis

love.graphics.polygon( mode, ... )

Arguments

DrawMode mode
How to draw the polygon.
number ...
The vertices of the polygon.

Returns

Nothing.

Function

Synopsis

love.graphics.polygon( mode, vertices )

Arguments

DrawMode mode
How to draw the polygon.
table vertices
The vertices of the polygon as a table.

Returns

Nothing.

Examples

Two ways of drawing the same triangle

Triangle drawn using love.graphics.polygon

This example shows how to give the coordinates explicitly and how to pass a table argument.

-- Giving the coordinates directly.
love.graphics.polygon("fill", 100,100, 200,100, 150,200)

-- Defining a table with the coordinates.
-- This table could be built incrementally too.
local vertices = {100,100, 200,100, 150,200}

-- Passing the table to the function as a second argument.
love.graphics.polygon("fill", vertices)

Draw concave polygon

local vertices  = {100,100, 200,100, 200,200, 300,200, 300,300, 100,300} -- Concave "L" shape.
local triangles = love.math.triangulate(vertices)

for i, triangle in ipairs(triangles) do
	love.graphics.polygon("fill", triangle)
end

Draw rotated rectangle

This is one way to draw a rotated rectangle.

function drawRotatedRectangle(mode, x, y, width, height, angle)
	local cosa, sina = math.cos(angle), math.sin(angle)

	local dx1, dy1 = width*cosa,   width*sina
	local dx2, dy2 = -height*sina, height*cosa

	local px1, py1 = x,         y
	local px2, py2 = x+dx1,     y+dy1
	local px3, py3 = x+dx1+dx2, y+dy1+dy2
	local px4, py4 = x+dx2,     y+dy2
	
	love.graphics.polygon(mode, px1,py1, px2,py2, px3,py3, px4,py4)
end

Draw rotated triangle

Triangle drawn using love.graphics.polygon
function drawTriangle (mode, x, y, length, width , angle) -- position, length, width and angle
	love.graphics.push()
	love.graphics.translate(x, y)
	love.graphics.rotate( angle )
	love.graphics.polygon(mode, -length/2, -width /2, -length/2, width /2, length/2, 0)
	love.graphics.pop() 
end


Pixel-perfect Hexadecagon

For better result it can be used with "rough" line style and "nearest" canvas filter.

function hexadecagon (mode, x, y, radius) -- same as [[love.graphics.circle|circle]]
	local w1, w2 = math.atan(0.21), math.atan(0.72) -- magic values
	local a = radius
	local b = radius*math.sin (w1)
	local c = radius*math.cos (w2)
	local d = radius*math.sin (w2)
	local vertices = {
		 a, b,  c, d,  d, c,  b, a, 
		-b, a, -d, c, -c, d, -a, b, 
		-a,-b, -c,-d, -d,-c, -b,-a, 
		 b,-a,  d,-c,  c,-d,  a,-b}
	love.graphics.translate (x+0.5, y+0.5)
	love.graphics.polygon (mode, vertices)
	love.graphics.translate (-x-0.5, -y-0.5)
end

canvas = love.graphics.newCanvas(width, height)
canvas:setFilter("nearest", "nearest")
love.graphics.setLineStyle("rough")
love.graphics.setCanvas (canvas)
	love.graphics.setColor (0,1,0)
	hexadecagon ("line", 200, 100, 60)
love.graphics.setCanvas ()

function love.draw()
	love.graphics.setColor (1,1,1)
	love.graphics.draw (canvas)
end

See Also


Other Languages