Canvas (简体中文)

Available since LÖVE 0.8.0

由Framebuffer重命名而来.

Canvas用于离屏渲染。可以把它看成是一种无形的屏幕，你可以在上面绘制一些东西，但直到你将它设置为可见的之前，它都不会被看见不可见的。它也被称为“纹理渲染(render to texture)”。

在Canvas上绘制一些不经常改变的东西（如背景图案）,然后再把Canvas绘制绘制出来来取代每个东西都独自绘制, 可以减少画面每帧拉伸操作的次数。

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.

有些很老的显卡不支持Canvas，如果你试图使用它们将抛出一个错误。在运行时使用 love.graphics.isSupported("canvas") 来检查是否支持。

构造函数

love.graphics.newCanvas

Creates a new Canvas.

0.8.0

函数

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.

父类

• Texture
• Drawable
• Object

范例

绘制一些东西到Canvas上，然后覆盖在画面上。

function love.load()
	canvas = love.graphics.newCanvas(800, 600)

	-- 在Canvas上用Alpha混合模式绘制一个矩形。
	love.graphics.setCanvas(canvas)
		canvas:clear()
		love.graphics.setBlendMode('alpha')
		love.graphics.setColor(255, 0, 0, 128)
		love.graphics.rectangle('fill', 0, 0, 100, 100)
	love.graphics.setCanvas()
end

function love.draw()
	love.graphics.setColor(255, 255, 255, 255)
	
	-- Canvas上的矩形已经使用alpha混合。
	-- 绘Canvas布本身时，以防止其他混合使用premultiplied混合模式。
	love.graphics.setBlendMode('premultiplied')
	love.graphics.draw(canvas)
	-- 展示Canvas使用了alpha混合模式的差异。
	love.graphics.setBlendMode('alpha')
	love.graphics.draw(canvas, 100, 0)

	-- 矩形直接画到与Alpha混合模式的画面。
	love.graphics.setBlendMode('alpha')
	love.graphics.setColor(255, 0, 0, 128)
	love.graphics.rectangle('fill', 200, 0, 100, 100)
end

参考

• love.graphics (简体中文)
• love.graphics.setCanvas
• love.graphics.isSupported

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