Difference between revisions of "Canvas"
(Color blending example) |
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love.graphics.setBlendMode 'alpha' | love.graphics.setBlendMode 'alpha' | ||
+ | -- love.graphics.setBlendMode 'premultiplied' -- use this to avoid a second alpha blend | ||
love.graphics.setColor(255,255,255,255) | love.graphics.setColor(255,255,255,255) | ||
love.graphics.draw(canvas) | love.graphics.draw(canvas) |
Revision as of 01:03, 7 June 2013
Available since LÖVE 0.8.0 |
It has been renamed from Framebuffer. |
A Canvas is used for off-screen rendering. Think of it as an invisible screen that you can draw to, but that will not be visible until you draw it to the actual visible screen. It is also known as "render to texture".
By drawing things that do not change position often (such as background items) to the Canvas, and then drawing the entire Canvas instead of each item, you can reduce the number of draw operations performed each frame.
Canvases can be susceptible to power of 2 syndrome. Most graphics cards that support Canvas should have non-PO2 texture support. However, there are some old cards that do not. Check with love.graphics.isSupported("npot") if it is supported.
Contents
Constructors
love.graphics.newCanvas | Creates a new Canvas. | 0.8.0 |
Functions
Canvas:clear | Clears the contents of a Canvas to a specific color. | 0.8.0 | 0.10.0 |
Canvas:generateMipmaps | Generates mipmaps for the Canvas, based on the contents of the highest-resolution mipmap level. | 11.0 | |
Canvas:getFSAA | Gets the number of FSAA samples used when drawing to the Canvas. | 0.9.1 | 0.10.0 |
Canvas:getFormat | Gets the texture format of the Canvas. | 0.9.1 | 11.0 |
Canvas:getImageData | Generates ImageData from the contents of the Canvas. | 0.8.0 | 0.10.0 |
Canvas:getMSAA | Gets the number of MSAA samples used when drawing to the Canvas. | 0.9.2 | |
Canvas:getMipmapMode | Gets the MipmapMode this Canvas was created with. | 11.0 | |
Canvas:getPixel | Gets the pixel at the specified position in a Canvas. | 0.9.0 | 0.10.0 |
Canvas:newImageData | Generates ImageData from the contents of the Canvas. | 0.10.0 | |
Canvas:renderTo | Render to a Canvas using a function. | 0.8.0 | |
Object:release | Immediately destroys the object's Lua reference. | 11.0 | |
Object:type | Gets the type of the object as a string. | ||
Object:typeOf | Checks whether an object is of a certain type. |
Supertypes
Examples
sample from the forum
http://love2d.org/forums/viewtopic.php?f=4&t=2136&start=20
Color blending is applied when rendering to a canvas and again when drawing the canvas.
canvas = love.graphics.newCanvas(800,600)
function love.draw()
-- the rectangle is alpha blended twice
canvas:clear()
canvas:renderTo(function()
love.graphics.setBlendMode 'alpha'
love.graphics.setColor(255,0,0,128)
love.graphics.rectangle('fill',0,0,100,100)
end)
love.graphics.setBlendMode 'alpha'
-- love.graphics.setBlendMode 'premultiplied' -- use this to avoid a second alpha blend
love.graphics.setColor(255,255,255,255)
love.graphics.draw(canvas)
-- the rectangle is alpha blended once
love.graphics.setBlendMode 'alpha'
love.graphics.setColor(255,0,0,128)
love.graphics.rectangle('fill',100,0,100,100)
end
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